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Types of Research – Explained with Examples

By DiscoverPhDs
October 2, 2020

Types of Research

Research is about using established methods to investigate a problem or question in detail with the aim of generating new knowledge about it.

It is a vital tool for scientific advancement because it allows researchers to prove or refute hypotheses based on clearly defined parameters, environments and assumptions. Due to this, it enables us to confidently contribute to knowledge as it allows research to be verified and replicated.

Knowing the types of research and what each of them focuses on will allow you to better plan your project, utilises the most appropriate methodologies and techniques and better communicate your findings to other researchers and supervisors.

Classification of Types of Research

There are various types of research that are classified according to their objective, depth of study, analysed data, time required to study the phenomenon and other factors. It’s important to note that a research project will not be limited to one type of research, but will likely use several.

According to its Purpose

Theoretical research.

Theoretical research, also referred to as pure or basic research, focuses on generating knowledge , regardless of its practical application. Here, data collection is used to generate new general concepts for a better understanding of a particular field or to answer a theoretical research question.

Results of this kind are usually oriented towards the formulation of theories and are usually based on documentary analysis, the development of mathematical formulas and the reflection of high-level researchers.

Applied Research

Here, the goal is to find strategies that can be used to address a specific research problem. Applied research draws on theory to generate practical scientific knowledge, and its use is very common in STEM fields such as engineering, computer science and medicine.

This type of research is subdivided into two types:

Technological applied research : looks towards improving efficiency in a particular productive sector through the improvement of processes or machinery related to said productive processes.
Scientific applied research : has predictive purposes. Through this type of research design, we can measure certain variables to predict behaviours useful to the goods and services sector, such as consumption patterns and viability of commercial projects.

According to your Depth of Scope

Exploratory research.

Exploratory research is used for the preliminary investigation of a subject that is not yet well understood or sufficiently researched. It serves to establish a frame of reference and a hypothesis from which an in-depth study can be developed that will enable conclusive results to be generated.

Because exploratory research is based on the study of little-studied phenomena, it relies less on theory and more on the collection of data to identify patterns that explain these phenomena.

Descriptive Research

The primary objective of descriptive research is to define the characteristics of a particular phenomenon without necessarily investigating the causes that produce it.

In this type of research, the researcher must take particular care not to intervene in the observed object or phenomenon, as its behaviour may change if an external factor is involved.

Explanatory Research

Explanatory research is the most common type of research method and is responsible for establishing cause-and-effect relationships that allow generalisations to be extended to similar realities. It is closely related to descriptive research, although it provides additional information about the observed object and its interactions with the environment.

Correlational Research

The purpose of this type of scientific research is to identify the relationship between two or more variables. A correlational study aims to determine whether a variable changes, how much the other elements of the observed system change.

According to the Type of Data Used

Qualitative research.

Qualitative methods are often used in the social sciences to collect, compare and interpret information, has a linguistic-semiotic basis and is used in techniques such as discourse analysis, interviews, surveys, records and participant observations.

In order to use statistical methods to validate their results, the observations collected must be evaluated numerically. Qualitative research, however, tends to be subjective, since not all data can be fully controlled. Therefore, this type of research design is better suited to extracting meaning from an event or phenomenon (the ‘why’) than its cause (the ‘how’).

Quantitative Research

Quantitative research study delves into a phenomena through quantitative data collection and using mathematical, statistical and computer-aided tools to measure them . This allows generalised conclusions to be projected over time.

According to the Degree of Manipulation of Variables

Experimental research.

It is about designing or replicating a phenomenon whose variables are manipulated under strictly controlled conditions in order to identify or discover its effect on another independent variable or object. The phenomenon to be studied is measured through study and control groups, and according to the guidelines of the scientific method.

Non-Experimental Research

Also known as an observational study, it focuses on the analysis of a phenomenon in its natural context. As such, the researcher does not intervene directly, but limits their involvement to measuring the variables required for the study. Due to its observational nature, it is often used in descriptive research.

Quasi-Experimental Research

It controls only some variables of the phenomenon under investigation and is therefore not entirely experimental. In this case, the study and the focus group cannot be randomly selected, but are chosen from existing groups or populations . This is to ensure the collected data is relevant and that the knowledge, perspectives and opinions of the population can be incorporated into the study.

According to the Type of Inference

Deductive investigation.

In this type of research, reality is explained by general laws that point to certain conclusions; conclusions are expected to be part of the premise of the research problem and considered correct if the premise is valid and the inductive method is applied correctly.

Inductive Research

In this type of research, knowledge is generated from an observation to achieve a generalisation. It is based on the collection of specific data to develop new theories.

Hypothetical-Deductive Investigation

It is based on observing reality to make a hypothesis, then use deduction to obtain a conclusion and finally verify or reject it through experience.

According to the Time in Which it is Carried Out

Longitudinal study (also referred to as diachronic research).

It is the monitoring of the same event, individual or group over a defined period of time. It aims to track changes in a number of variables and see how they evolve over time. It is often used in medical, psychological and social areas .

Cross-Sectional Study (also referred to as Synchronous Research)

Cross-sectional research design is used to observe phenomena, an individual or a group of research subjects at a given time.

According to The Sources of Information

Primary research.

This fundamental research type is defined by the fact that the data is collected directly from the source, that is, it consists of primary, first-hand information.

Secondary research

Unlike primary research, secondary research is developed with information from secondary sources, which are generally based on scientific literature and other documents compiled by another researcher.

According to How the Data is Obtained

Documentary (cabinet).

Documentary research, or secondary sources, is based on a systematic review of existing sources of information on a particular subject. This type of scientific research is commonly used when undertaking literature reviews or producing a case study.

Field research study involves the direct collection of information at the location where the observed phenomenon occurs.

From Laboratory

Laboratory research is carried out in a controlled environment in order to isolate a dependent variable and establish its relationship with other variables through scientific methods.

Mixed-Method: Documentary, Field and/or Laboratory

Mixed research methodologies combine results from both secondary (documentary) sources and primary sources through field or laboratory research.

Scientific misconduct can be described as a deviation from the accepted standards of scientific research, study and publication ethics.

The purpose of research is to enhance society by advancing knowledge through developing scientific theories, concepts and ideas – find out more on what this involves.

The Thurstone Scale is used to quantify the attitudes of people being surveyed, using a format of ‘agree-disagree’ statements.

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The unit of analysis refers to the main parameter that you’re investigating in your research project or study.

Freya’s in the final year of her PhD at the University of Leeds. Her project is about improving the precision of observations between collocated ground-based weather radar and airborne platforms.

Daniel is a third year PhD student at the University of York. His research is based around self-play training in multiagent systems; training AIs on a game such that they improve overtime.

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Knowledge Base
Methodology

Research Methods | Definition, Types, Examples

Research methods are specific procedures for collecting and analysing data. Developing your research methods is an integral part of your research design . When planning your methods, there are two key decisions you will make.

First, decide how you will collect data . Your methods depend on what type of data you need to answer your research question :

Qualitative vs quantitative : Will your data take the form of words or numbers?
Primary vs secondary : Will you collect original data yourself, or will you use data that have already been collected by someone else?
Descriptive vs experimental : Will you take measurements of something as it is, or will you perform an experiment?

Second, decide how you will analyse the data .

For quantitative data, you can use statistical analysis methods to test relationships between variables.
For qualitative data, you can use methods such as thematic analysis to interpret patterns and meanings in the data.

Methods for collecting data, examples of data collection methods, methods for analysing data, examples of data analysis methods, frequently asked questions about methodology.

Data are the information that you collect for the purposes of answering your research question . The type of data you need depends on the aims of your research.

Qualitative vs quantitative data

Your choice of qualitative or quantitative data collection depends on the type of knowledge you want to develop.

For questions about ideas, experiences and meanings, or to study something that can’t be described numerically, collect qualitative data .

If you want to develop a more mechanistic understanding of a topic, or your research involves hypothesis testing , collect quantitative data .

You can also take a mixed methods approach, where you use both qualitative and quantitative research methods.

Primary vs secondary data

Primary data are any original information that you collect for the purposes of answering your research question (e.g. through surveys , observations and experiments ). Secondary data are information that has already been collected by other researchers (e.g. in a government census or previous scientific studies).

If you are exploring a novel research question, you’ll probably need to collect primary data. But if you want to synthesise existing knowledge, analyse historical trends, or identify patterns on a large scale, secondary data might be a better choice.

Descriptive vs experimental data

In descriptive research , you collect data about your study subject without intervening. The validity of your research will depend on your sampling method .

In experimental research , you systematically intervene in a process and measure the outcome. The validity of your research will depend on your experimental design .

To conduct an experiment, you need to be able to vary your independent variable , precisely measure your dependent variable, and control for confounding variables . If it’s practically and ethically possible, this method is the best choice for answering questions about cause and effect.

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Your data analysis methods will depend on the type of data you collect and how you prepare them for analysis.

Data can often be analysed both quantitatively and qualitatively. For example, survey responses could be analysed qualitatively by studying the meanings of responses or quantitatively by studying the frequencies of responses.

Qualitative analysis methods

Qualitative analysis is used to understand words, ideas, and experiences. You can use it to interpret data that were collected:

From open-ended survey and interview questions, literature reviews, case studies, and other sources that use text rather than numbers.
Using non-probability sampling methods .

Qualitative analysis tends to be quite flexible and relies on the researcher’s judgement, so you have to reflect carefully on your choices and assumptions.

Quantitative analysis methods

Quantitative analysis uses numbers and statistics to understand frequencies, averages and correlations (in descriptive studies) or cause-and-effect relationships (in experiments).

You can use quantitative analysis to interpret data that were collected either:

During an experiment.
Using probability sampling methods .

Because the data are collected and analysed in a statistically valid way, the results of quantitative analysis can be easily standardised and shared among researchers.

Quantitative research deals with numbers and statistics, while qualitative research deals with words and meanings.

Quantitative methods allow you to test a hypothesis by systematically collecting and analysing data, while qualitative methods allow you to explore ideas and experiences in depth.

In mixed methods research , you use both qualitative and quantitative data collection and analysis methods to answer your research question .

A sample is a subset of individuals from a larger population. Sampling means selecting the group that you will actually collect data from in your research.

For example, if you are researching the opinions of students in your university, you could survey a sample of 100 students.

Statistical sampling allows you to test a hypothesis about the characteristics of a population. There are various sampling methods you can use to ensure that your sample is representative of the population as a whole.

The research methods you use depend on the type of data you need to answer your research question .

If you want to measure something or test a hypothesis , use quantitative methods . If you want to explore ideas, thoughts, and meanings, use qualitative methods .
If you want to analyse a large amount of readily available data, use secondary data. If you want data specific to your purposes with control over how they are generated, collect primary data.
If you want to establish cause-and-effect relationships between variables , use experimental methods. If you want to understand the characteristics of a research subject, use descriptive methods.

Methodology refers to the overarching strategy and rationale of your research project . It involves studying the methods used in your field and the theories or principles behind them, in order to develop an approach that matches your objectives.

Methods are the specific tools and procedures you use to collect and analyse data (e.g. experiments, surveys , and statistical tests ).

In shorter scientific papers, where the aim is to report the findings of a specific study, you might simply describe what you did in a methods section .

In a longer or more complex research project, such as a thesis or dissertation , you will probably include a methodology section , where you explain your approach to answering the research questions and cite relevant sources to support your choice of methods.

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An introduction to different types of study design

Posted on 6th April 2021 by Hadi Abbas

Study designs are the set of methods and procedures used to collect and analyze data in a study.

Broadly speaking, there are 2 types of study designs: descriptive studies and analytical studies.

Descriptive studies

Describes specific characteristics in a population of interest
The most common forms are case reports and case series
In a case report, we discuss our experience with the patient’s symptoms, signs, diagnosis, and treatment
In a case series, several patients with similar experiences are grouped.

Analytical Studies

Analytical studies are of 2 types: observational and experimental.

Observational studies are studies that we conduct without any intervention or experiment. In those studies, we purely observe the outcomes. On the other hand, in experimental studies, we conduct experiments and interventions.

Observational studies

Observational studies include many subtypes. Below, I will discuss the most common designs.

Cross-sectional study:

This design is transverse where we take a specific sample at a specific time without any follow-up
It allows us to calculate the frequency of disease ( p revalence ) or the frequency of a risk factor
This design is easy to conduct
For example – if we want to know the prevalence of migraine in a population, we can conduct a cross-sectional study whereby we take a sample from the population and calculate the number of patients with migraine headaches.

Cohort study:

We conduct this study by comparing two samples from the population: one sample with a risk factor while the other lacks this risk factor
It shows us the risk of developing the disease in individuals with the risk factor compared to those without the risk factor ( RR = relative risk )
Prospective : we follow the individuals in the future to know who will develop the disease
Retrospective : we look to the past to know who developed the disease (e.g. using medical records)
This design is the strongest among the observational studies
For example – to find out the relative risk of developing chronic obstructive pulmonary disease (COPD) among smokers, we take a sample including smokers and non-smokers. Then, we calculate the number of individuals with COPD among both.

Case-Control Study:

We conduct this study by comparing 2 groups: one group with the disease (cases) and another group without the disease (controls)
This design is always retrospective
We aim to find out the odds of having a risk factor or an exposure if an individual has a specific disease (Odds ratio)
Relatively easy to conduct
For example – we want to study the odds of being a smoker among hypertensive patients compared to normotensive ones. To do so, we choose a group of patients diagnosed with hypertension and another group that serves as the control (normal blood pressure). Then we study their smoking history to find out if there is a correlation.

Experimental Studies

Also known as interventional studies
Can involve animals and humans
Pre-clinical trials involve animals
Clinical trials are experimental studies involving humans
In clinical trials, we study the effect of an intervention compared to another intervention or placebo. As an example, I have listed the four phases of a drug trial:

I: We aim to assess the safety of the drug ( is it safe ? )

II: We aim to assess the efficacy of the drug ( does it work ? )

III: We want to know if this drug is better than the old treatment ( is it better ? )

IV: We follow-up to detect long-term side effects ( can it stay in the market ? )

In randomized controlled trials, one group of participants receives the control, while the other receives the tested drug/intervention. Those studies are the best way to evaluate the efficacy of a treatment.

Finally, the figure below will help you with your understanding of different types of study designs.

A visual diagram describing the following. Two types of epidemiological studies are descriptive and analytical. Types of descriptive studies are case reports, case series, descriptive surveys. Types of analytical studies are observational or experimental. Observational studies can be cross-sectional, case-control or cohort studies. Types of experimental studies can be lab trials or field trials.

References (pdf)

You may also be interested in the following blogs for further reading:

An introduction to randomized controlled trials

Case-control and cohort studies: a brief overview

Cohort studies: prospective and retrospective designs

Prevalence vs Incidence: what is the difference?

No Comments on An introduction to different types of study design

you are amazing one!! if I get you I’m working with you! I’m student from Ethiopian higher education. health sciences student

Very informative and easy understandable

You are my kind of doctor. Do not lose sight of your objective.

Wow very erll explained and easy to understand

I’m Khamisu Habibu community health officer student from Abubakar Tafawa Balewa university teaching hospital Bauchi, Nigeria, I really appreciate your write up and you have make it clear for the learner. thank you

well understood,thank you so much

Well understood…thanks

Simply explained. Thank You.

Thanks a lot for this nice informative article which help me to understand different study designs that I felt difficult before

That’s lovely to hear, Mona, thank you for letting the author know how useful this was. If there are any other particular topics you think would be useful to you, and are not already on the website, please do let us know.

it is very informative and useful.

thank you statistician

Fabulous to hear, thank you John.

Thanks for this information

Thanks so much for this information….I have clearly known the types of study design Thanks

That’s so good to hear, Mirembe, thank you for letting the author know.

Very helpful article!! U have simplified everything for easy understanding

I’m a health science major currently taking statistics for health care workers…this is a challenging class…thanks for the simified feedback.

That’s good to hear this has helped you. Hopefully you will find some of the other blogs useful too. If you see any topics that are missing from the website, please do let us know!

Hello. I liked your presentation, the fact that you ranked them clearly is very helpful to understand for people like me who is a novelist researcher. However, I was expecting to read much more about the Experimental studies. So please direct me if you already have or will one day. Thank you

Dear Ay. My sincere apologies for not responding to your comment sooner. You may find it useful to filter the blogs by the topic of ‘Study design and research methods’ – here is a link to that filter: https://s4be.cochrane.org/blog/topic/study-design/ This will cover more detail about experimental studies. Or have a look on our library page for further resources there – you’ll find that on the ‘Resources’ drop down from the home page.

However, if there are specific things you feel you would like to learn about experimental studies, that are missing from the website, it would be great if you could let me know too. Thank you, and best of luck. Emma

Great job Mr Hadi. I advise you to prepare and study for the Australian Medical Board Exams as soon as you finish your undergrad study in Lebanon. Good luck and hope we can meet sometime in the future. Regards ;)

You have give a good explaination of what am looking for. However, references am not sure of where to get them from.

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Cluster Randomized Trials: Concepts

This blog summarizes the concepts of cluster randomization, and the logistical and statistical considerations while designing a cluster randomized controlled trial.

Expertise-based Randomized Controlled Trials

This blog summarizes the concepts of Expertise-based randomized controlled trials with a focus on the advantages and challenges associated with this type of study.

A well-designed cohort study can provide powerful results. This blog introduces prospective and retrospective cohort studies, discussing the advantages, disadvantages and use of these type of study designs.

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1.3: Types of Research Studies and How To Interpret Them

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Alice Callahan, Heather Leonard, & Tamberly Powell

Alice Callahan, Heather Leonard, & Tamberly Powell
Lane Community College via OpenOregon

The field of nutrition is dynamic, and our understanding and practices are always evolving. Nutrition scientists are continuously conducting new research and publishing their findings in peer-reviewed journals. This adds to scientific knowledge, but it’s also of great interest to the public, so nutrition research often shows up in the news and other media sources. You might be interested in nutrition research to inform your own eating habits, or if you work in a health profession, so that you can give evidence-based advice to others. Making sense of science requires that you understand the types of research studies used and their limitations.

The Hierarchy of Nutrition Evidence

Researchers use many different types of study designs depending on the question they are trying to answer, as well as factors such as time, funding, and ethical considerations. The study design affects how we interpret the results and the strength of the evidence as it relates to real-life nutrition decisions. It can be helpful to think about the types of studies within a pyramid representing a hierarchy of evidence, where the studies at the bottom of the pyramid usually give us the weakest evidence with the least relevance to real-life nutrition decisions, and the studies at the top offer the strongest evidence, with the most relevance to real-life nutrition decisions .

Figure 2.1. Hierarchy of research design and levels of scientific evidence with the strongest studies at the top and the weakest at the bottom.

The pyramid also represents a few other general ideas. There tend to be more studies published using the methods at the bottom of the pyramid, because they require less time, money, and other resources. When researchers want to test a new hypothesis , they often start with the study designs at the bottom of the pyramid , such as in vitro, animal, or observational studies. Intervention studies are more expensive and resource-intensive, so there are fewer of these types of studies conducted. But they also give us higher quality evidence, so they’re an important next step if observational and non-human studies have shown promising results. Meta-analyses and systematic reviews combine the results of many studies already conducted, so they help researchers summarize scientific knowledge on a topic.

Non-Human Studies: In Vitro & Animal Studies

The simplest form of nutrition research is an in vitro study . In vitro means “within glass,” (although plastic is used more commonly today) and these experiments are conducted within flasks, dishes, plates, and test tubes. One common form of in vitro research is cell culture. This involves growing cells in flasks and dishes. In order for cells to grow, they need a nutrient source. For cell culture, the nutrient source is referred to as media. Media supplies nutrients to the cells in vitro similarly to how blood performs this function within the body. Most cells adhere to the bottom of the flask and are so small that a microscope is needed to see them. The cells are grown inside an incubator, which is a device that provides the optimal temperature, humidity, and carbon dioxide (CO2CO2) concentrations for cells and microorganisms. By imitating the body's temperature and CO2CO2 levels (37 degrees Celsius, 5% CO2CO2), the incubator allows cells to grow even though they are outside the body.

A limitation of in vitro research compared to in vivo research is that it typically does not take digestion or bioavailability into account. This means that the concentration used might not be physiologically possible (it might be much higher) and that digestion and metabolism of what is being provided to cells may not be taken into account. Cell-based in vitro research is not as complex of a biological system as animals or people that have tissues, organs, etc. working together as well.

Since these studies are performed on isolated cells or tissue samples, they are less expensive and time-intensive than animal or human studies. In vitro studies are vital for zooming in on biological mechanisms, to see how things work at the cellular or molecular level. However, these studies shouldn’t be used to draw conclusions about how things work in humans (or even animals), because we can’t assume that the results will apply to a whole, living organism.

Two photos representing lab research. At left, a person appearing to be a woman with long dark hair and dark skin handles tiny tubes in a black bucket of ice. More tubes surround the bucket on the table. At right, a white mouse with red eyes peers out of an opening of a cage.

Animal studies are one form of in vivo research, which translates to “within the living.” Rats and mice are the most common animals used in nutrition research. Animals are often used in research that would be unethical to conduct in humans. Another advantage of animal dietary studies is that researchers can control exactly what the animals eat. In human studies, researchers can tell subjects what to eat and even provide them with the food, but they may not stick to the planned diet. People are also not very good at estimating, recording, or reporting what they eat and in what quantities. In addition, animal studies typically do not cost as much as human studies.

There are some important limitations of animal research. First, an animal’s metabolism and physiology are different from humans. Plus, animal models of disease (cancer, cardiovascular disease, etc.), although similar, are different from human diseases. Animal research is considered preliminary, and while it can be very important to the process of building scientific understanding and informing the types of studies that should be conducted in humans, animal studies shouldn’t be considered relevant to real-life decisions about how people eat.

Observational Studies

Observational studies in human nutrition collect information on people’s dietary patterns or nutrient intake and look for associations with health outcomes. Observational studies do not give participants a treatment or intervention; instead, they look at what they’re already doing and see how it relates to their health. These types of study designs can only identify correlations (relationships) between nutrition and health; they can’t show that one factor causes another. (For that, we need intervention studies, which we’ll discuss in a moment.) Observational studies that describe factors correlated with human health are also called epidemiological studies . 1

Epidemiology is defined as the study of human populations. These studies often investigate the relationship between dietary consumption and disease development. There are three main types of epidemiological studies: cross-sectional, case-control, and prospective cohort studies.

One example of a nutrition hypothesis that has been investigated using observational studies is that eating a Mediterranean diet reduces the risk of developing cardiovascular disease. (A Mediterranean diet focuses on whole grains, fruits and vegetables, beans and other legumes, nuts, olive oil, herbs, and spices. It includes small amounts of animal protein (mostly fish), dairy, and red wine. 2 ) There are three main types of observational studies, all of which could be used to test hypotheses about the Mediterranean diet:

Cohort studies follow a group of people (a cohort) over time, measuring factors such as diet and health outcomes. A cohort study of the Mediterranean diet would ask a group of people to describe their diet, and then researchers would track them over time to see if those eating a Mediterranean diet had a lower incidence of cardiovascular disease.
Case-control studies compare a group of cases and controls, looking for differences between the two groups that might explain their different health outcomes. For example, researchers might compare a group of people with cardiovascular disease with a group of healthy controls to see whether there were more controls or cases that followed a Mediterranean diet.
Cross-sectional studies collect information about a population of people at one point in time. For example, a cross-sectional study might compare the dietary patterns of people from different countries to see if diet correlates with the prevalence of cardiovascular disease in the different countries.

There are two types of cohort studies: retrospective and prospective. Retrospective studies look at what happened in the past, and they’re considered weaker because they rely on people’s memory of what they ate or how they felt in the past. Prospective cohort studies, which enroll a cohort and follow them into the future, are usually considered the strongest type of observational study design.

Most cohort studies are prospective. Initial information is collected (usually by food frequency questionnaires) on the intake of a cohort of people at baseline, or the beginning. This cohort is then followed over time (normally many years) to quantify health outcomes of the individual within it. Cohort studies are normally considered to be more robust than case-control studies, because these studies do not start with diseased people and normally do not require people to remember their dietary habits in the distant past or before they developed a disease. An example of a prospective cohort study would be if you filled out a questionnaire on your current dietary habits and are then followed into the future to see if you develop osteoporosis. As shown below, instead of separating based on disease versus disease-free, individuals are separated based on exposure. In this example, those who are exposed are more likely to be diseased than those who were not exposed.

Using trans-fat intake again as the exposure and cardiovascular disease as the disease, the figure would be expected to look like this:

There are several well-known examples of prospective cohort studies that have described important correlations between diet and disease:

Framingham Heart Study : Beginning in 1948, this study has followed the residents of Framingham, Massachusetts to identify risk factors for heart disease.
Health Professionals Follow-Up Study : This study started in 1986 and enrolled 51,529 male health professionals (dentists, pharmacists, optometrists, osteopathic physicians, podiatrists, and veterinarians), who complete diet questionnaires every 2 years.
Nurses Health Studies : Beginning in 1976, these studies have enrolled three large cohorts of nurses with a total of 280,000 participants. Participants have completed detailed questionnaires about diet, other lifestyle factors (smoking and exercise, for example), and health outcomes.

Observational studies have the advantage of allowing researchers to study large groups of people in the real world, looking at the frequency and pattern of health outcomes and identifying factors that correlate with them. But even very large observational studies may not apply to the population as a whole. For example, the Health Professionals Follow-Up Study and the Nurses Health Studies include people with above-average knowledge of health. In many ways, this makes them ideal study subjects, because they may be more motivated to be part of the study and to fill out detailed questionnaires for years. However, the findings of these studies may not apply to people with less baseline knowledge of health.

We’ve already mentioned another important limitation of observational studies—that they can only determine correlation, not causation. A prospective cohort study that finds that people eating a Mediterranean diet have a lower incidence of heart disease can only show that the Mediterranean diet is correlated with lowered risk of heart disease. It can’t show that the Mediterranean diet directly prevents heart disease. Why? There are a huge number of factors that determine health outcomes such as heart disease, and other factors might explain a correlation found in an observational study. For example, people who eat a Mediterranean diet might also be the same kind of people who exercise more, sleep more, have a higher income (fish and nuts can be expensive!), or be less stressed. These are called confounding factors ; they’re factors that can affect the outcome in question (i.e., heart disease) and also vary with the factor being studied (i.e., Mediterranean diet).

Intervention Studies

Intervention studies , also sometimes called experimental studies or clinical trials, include some type of treatment or change imposed by the researcher. Examples of interventions in nutrition research include asking participants to change their diet, take a supplement, or change the time of day that they eat. Unlike observational studies, intervention studies can provide evidence of cause and effect , so they are higher in the hierarchy of evidence pyramid.

Randomization: The gold standard for intervention studies is the randomized controlled trial (RCT) . In an RCT, study subjects are recruited to participate in the study. They are then randomly assigned into one of at least two groups, one of which is a control group (this is what makes the study controlled ).

Randomization is the process of randomly assigning subjects to groups to decrease bias. Bias is a systematic error that may influence results. Bias can occur in assigning subjects to groups in a way that will influence the results. An example of bias in a study of an antidepressant drug is shown below. In this nonrandomized antidepressant drug example, researchers (who know what the subjects are receiving) put depressed subjects into the placebo group, while "less depressed" subjects are put into the antidepressant drug group. As a result, even if the drug isn't effective, the group assignment may make the drug appear effective, thus biasing the results as shown below.

This is a bit of an extreme example, but even if the researchers are trying to prevent bias, sometimes bias can still occur. However, if the subjects are randomized, the sick and the healthy people will ideally be equally distributed between the groups. Thus, the trial will be unbiased and a true test of whether or not the drug is effective.

Here is another example. In an RCT to study the effects of the Mediterranean diet on cardiovascular disease development, researchers might ask the control group to follow a low-fat diet (typically recommended for heart disease prevention) and the intervention group to eat a Mediterranean diet. The study would continue for a defined period of time (usually years to study an outcome like heart disease), at which point the researchers would analyze their data to see if more people in the control or Mediterranean diet had heart attacks or strokes. Because the treatment and control groups were randomly assigned, they should be alike in every other way except for diet, so differences in heart disease could be attributed to the diet. This eliminates the problem of confounding factors found in observational research, and it’s why RCTs can provide evidence of causation, not just correlation.

Imagine for a moment what would happen if the two groups weren’t randomly assigned. What if the researchers let study participants choose which diet they’d like to adopt for the study? They might, for whatever reason, end up with more overweight people who smoke and have high blood pressure in the low-fat diet group, and more people who exercised regularly and had already been eating lots of olive oil and nuts for years in the Mediterranean diet group. If they found that the Mediterranean diet group had fewer heart attacks by the end of the study, they would have no way of knowing if this was because of the diet or because of the underlying differences in the groups. In other words, without randomization, their results would be compromised by confounding factors, with many of the same limitations as observational studies.

Placebo: In an RCT of a supplement, the control group would receive a placebo—a “fake” treatment that contains no active ingredients, such as a sugar pill. The use of a placebo is necessary in medical research because of a phenomenon known as the placebo effect. The placebo effect results in a beneficial effect because of a subject’s belief in the treatment, even though there is no treatment actually being administered. An example would be an athlete who consumes a sports drink and runs the 100-meter dash in 11.00 seconds. The athlete then, under the exact same conditions, drinks what he is told is "Super Duper Sports Drink" and runs the 100-meter dash in 10.50 seconds. But what the athlete didn't know was that Super Duper Sports Drink was the Sports Drink + Food Coloring. There was nothing different between the drinks, but the athlete believed that the "Super Duper Sports Drink" was going to help him run faster, so he did. This improvement is due to the placebo effect.

A cartoon depicts the study described in the text. At left is shown the "super duper sports drink" (sports drink plus food coloring) in orange. At right is the regular sports drink in green. A cartoon guy with yellow hair is pictured sprinting. The time with the super duper sports drink is 10.50 seconds, and the time with the regular sports drink is 11.00 seconds. The image reads "the improvement is the placebo effect."

Blinding is a technique to prevent bias in intervention studies. In a study without blinding, the subject and the researchers both know what treatment the subject is receiving. This can lead to bias if the subject or researcher has expectations about the treatment working, so these types of trials are used less frequently. It’s best if a study is double-blind , meaning that neither the researcher nor the subject knows what treatment the subject is receiving. It’s relatively simple to double-blind a study where subjects are receiving a placebo or treatment pill because they could be formulated to look and taste the same. In a single-blind study , either the researcher or the subject knows what treatment they’re receiving, but not both. Studies of diets—such as the Mediterranean diet example—often can’t be double-blinded because the study subjects know whether or not they’re eating a lot of olive oil and nuts. However, the researchers who are checking participants’ blood pressure or evaluating their medical records could be blinded to their treatment group, reducing the chance of bias.

Open-label study:

Single-blinded study:

Double-blinded study:

Like all studies, RCTs and other intervention studies do have some limitations. They can be difficult to carry on for long periods of time and require that participants remain compliant with the intervention. They’re also costly and often have smaller sample sizes. Furthermore, it is unethical to study certain interventions. (An example of an unethical intervention would be to advise one group of pregnant mothers to drink alcohol to determine its effects on pregnancy outcomes because we know that alcohol consumption during pregnancy damages the developing fetus.)

VIDEO: “ Not all scientific studies are created equal ” by David H. Schwartz, YouTube (April 28, 2014), 4:26.

Meta-Analyses and Systematic Reviews

At the top of the hierarchy of evidence pyramid are systematic reviews and meta-analyses . You can think of these as “studies of studies.” They attempt to combine all of the relevant studies that have been conducted on a research question and summarize their overall conclusions. Researchers conducting a systematic review formulate a research question and then systematically and independently identify, select, evaluate, and synthesize all high-quality evidence that relates to the research question. Since systematic reviews combine the results of many studies, they help researchers produce more reliable findings. A meta-analysis is a type of systematic review that goes one step further, combining the data from multiple studies and using statistics to summarize it, as if creating a mega-study from many smaller studies . 4

However, even systematic reviews and meta-analyses aren’t the final word on scientific questions. For one thing, they’re only as good as the studies that they include. The Cochrane Collaboration is an international consortium of researchers who conduct systematic reviews in order to inform evidence-based healthcare, including nutrition, and their reviews are among the most well-regarded and rigorous in science. For the most recent Cochrane review of the Mediterranean diet and cardiovascular disease, two authors independently reviewed studies published on this question. Based on their inclusion criteria, 30 RCTs with a total of 12,461 participants were included in the final analysis. However, after evaluating and combining the data, the authors concluded that “despite the large number of included trials, there is still uncertainty regarding the effects of a Mediterranean‐style diet on cardiovascular disease occurrence and risk factors in people both with and without cardiovascular disease already.” Part of the reason for this uncertainty is that different trials found different results, and the quality of the studies was low to moderate. Some had problems with their randomization procedures, for example, and others were judged to have unreliable data. That doesn’t make them useless, but it adds to the uncertainty about this question, and uncertainty pushes the field forward towards more and better studies. The Cochrane review authors noted that they found seven ongoing trials of the Mediterranean diet, so we can hope that they’ll add more clarity to this question in the future. 5

Science is an ongoing process. It’s often a slow process, and it contains a lot of uncertainty, but it’s our best method of building knowledge of how the world and human life works. Many different types of studies can contribute to scientific knowledge. None are perfect—all have limitations—and a single study is never the final word on a scientific question. Part of what advances science is that researchers are constantly checking each other’s work, asking how it can be improved and what new questions it raises.

Attributions:

“Chapter 1: The Basics” from Lindshield, B. L. Kansas State University Human Nutrition (FNDH 400) Flexbook. goo.gl/vOAnR , CC BY-NC-SA 4.0
“The Broad Role of Nutritional Science,” section 1.3 from the book An Introduction to Nutrition (v. 1.0), CC BY-NC-SA 3.0

References:

1 Thiese, M. S. (2014). Observational and interventional study design types; an overview. Biochemia Medica , 24 (2), 199–210. https://doi.org/10.11613/BM.2014.022
2 Harvard T.H. Chan School of Public Health. (2018, January 16). Diet Review: Mediterranean Diet . The Nutrition Source. https://www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/mediterranean-diet/
3 Ross, R., Gray, C. M., & Gill, J. M. R. (2015). Effects of an Injected Placebo on Endurance Running Performance. Medicine and Science in Sports and Exercise , 47 (8), 1672–1681. https://doi.org/10.1249/MSS.0000000000000584
4 Hooper, A. (n.d.). LibGuides: Systematic Review Resources: Systematic Reviews vs Other Types of Reviews . Retrieved February 7, 2020, from //libguides.sph.uth.tmc.edu/c.php?g=543382&p=5370369
5 Rees, K., Takeda, A., Martin, N., Ellis, L., Wijesekara, D., Vepa, A., Das, A., Hartley, L., & Stranges, S. (2019). Mediterranean‐style diet for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews , 3 . doi.org/10.1002/14651858.CD009825.pub3
6Levin K. (2006) Study design III: Cross-sectional studies. Evidence - Based Dentistry 7(1): 24.
Figure 2.3. The hierarchy of evidence by Alice Callahan, is licensed under CC BY 4.0
Research lab photo by National Cancer Institute on Unsplas h ; mouse photo by vaun0815 on Unsplash
Figure 2.4. “Placebo effect example” by Lindshield, B. L. Kansas State University Human Nutrition (FNDH 400) Flexbook. goo.gl/vOAnR

8 Different Types Of Research [With Examples] | In 2024

Research is a detailed, systematic study of a specific problem or concern using various methodologies set by professional fields and academic disciplines. It involves collecting necessary data, documenting critical information, and analyzing and interpreting that data/information.

Research is conducted to

Assess the validity of a theory or an interpretive framework.
Provide outcomes that can help with social, professional, and scientific evolution.
Generate new concepts and questions for further inquiries.

In general, a professional researcher (usually a Psy.D. or Ph.D.) turns a specific problem into a hypothesis or an answerable question by analyzing previous studies on the related topic, performing experiments, and reviewing outcomes.

Research can be about anything. From science and business to psychology and political issues, there are literally countless topics to cover. One can categorize different types of research depending on the discipline and field.

For example, the outcome of a study is heavily influenced by the type of knowledge researchers aim to produce, the type of data they collect, the techniques used to sample those data, the timescale and location of the study, and many other factors.

It is also important to note that a research project may not necessarily involve single research. Instead, it may utilize various research methodologies to generate effective outcomes.

Let’s dig deeper and find ways to categorize research methodologies and how they are different from each other.

Table of Contents

8. According to the Depth of Scope

8.1 exploratory research.

Characteristics : Low cost; interactive and open-ended

Exploratory research is conducted to study problems that haven’t been clearly defined yet. The objective is to collect preliminary data to define problems and suggest hypotheses.

While it sounds difficult to analyze something that has no prior information, several proven methods are available for collecting data and selecting the most suitable research design and variables. This includes in-depth interviews, focus groups, surveys, case studies, and formal and informal discussions with management, employees, consumers, or competitors.

Example

A study to find out whether putting more items on the menu will generate more orders. If yes, then what items can be added with minimum expenses?
An assessment of the role of business responsibility on consumer behavior in pharmaceutical in London.

Once the data is collected, the researcher continues the study through descriptive investigation. The findings can help other researchers figure out potential causes for the problem, which can be analyzed in detail in the following studies.

This type of research doesn’t provide a conclusive solution. Instead, it explores the topic with varying levels of depth. In simple terms, it’s a kind of initial research that forms the basis of more conclusive studies.

8.2 Descriptive Research

Characteristics : Cost-effective; quick to conduct; quantitative in nature

Descriptive research answers questions relating to “what,” describing the nature of demographics under study. It doesn’t focus on the “why” of the research subject. More specifically, it describes the attributes of the variables in the study without changing them.

Descriptive research is generally used to analyze the background of a problem and obtain insights required to carry out further study. It is utilized in many different ways by various businesses, especially when it’s about collecting data about the target audience.

Market researchers want to analyze consumers’ habits.
A university wants to understand if students will access online lessons rather than textbooks.

Since this type of research is effective in identifying patterns between variables and describing them, researchers can use the findings in further studies. It helps researchers to further figure out why certain patterns have been formed and how they are related to each other. In short, it gives analysts a direction toward insightful research.

8.3 Explanatory Research

Characteristics : Allows for increased understanding of the phenomenon and its causes

Explanatory research describes why certain phenomena work the way they do. It answers the “why” questions by connecting different ideas and establishing cause-and-effect relationships.

Explanatory research isn’t conducted until researchers obtain enough information to start predicting future outcomes with some accuracy.

Most studies begin with exploratory research and then proceed to descriptive research and explanatory research. Explanatory research is conducted when a researcher has just started the analysis and wishes to understand the problem more clearly.

Descriptive research defines the problem in detail. Explanatory research elaborates on how different parameters come together and interact.

A university conducting research to understand the connection between popularity and bullying
A study on students’ addiction to smartphones (that primarily explains the reason behind addiction and factors that contribute to the addiction)

Explanatory research usually involves literature research, in-depth interviews, focus group research, and case studies.

Literature research involves gathering searching information from newspapers, journals, and other trusted sources. Interviews, on the other hand, involve an expert in the field who can explain the topic under investigation.

7. According To The Type Of Inference

7.1 deductive research.

Characteristics : Explains causal relationships between concepts and variables; more narrow in nature

Deductive reasoning is a top-down approach — Researchers start by formulating a theory about the topic of interest and then narrowing it down into more specific hypotheses that can be tested.

In other words, deductive research follows the path of logic most closely. It begins with a theory and leads to a new hypothesis. The hypothesis is then tested against real-world data, and outcomes lead to a confirmation or a rejection of the hypothesis.

In 2009, a team of researchers hypothesized that law enforcement’s response would be less vigorous in regions that had a stronger history of racial violence. They tested it by examining the data on states’ lynching histories and hate crime responses and found that their hypothesis was true.

7.2 Inductive Research

Characteristics : More open-ended and exploratory

Inductive research is the exact opposite of deductive research. It starts with certain observations and leads to generalizations and theories. More specifically, this bottom-up approach involves identifying patterns, formulating some uncertain hypotheses, and developing general conclusions.

The conclusion drawn on the basis of the inductive method can be invalidated or never be proven.

Example

Let’s say you observe 100 flights from affordable airlines. All of them were delayed by at least 15 minutes, which is in line with your theory. But you can never prove that the next low-cost flight will be delayed. Still, your conclusion can be made more reliable with more datasets.

Unlike deductive research, which is perceived to be related to quantitative methods, the applications of inductive research are linked with qualitative methods of data collection and data analysis.

Both inductive and deductive methods can be used together for a complete understanding of the topic.

7.3 Hypothetico-deductive Research

Characteristics : Belongs to the epistemological approach of practical science

Hypothetico-deductive is a method for developing scientific theories. It is based on observing reality to make a hypothesis, using deduction to form a conclusion, and finally, verifying or disproving it by using empirical evidence derived from various observations and experiments.

Suppose your laptop fails to switch on. You may consider a hypothesis that the battery is dead. So, you predict that the laptop will work properly once you replace the battery. When you replace the battery, you conduct an experiment to test your prediction. If the laptop still doesn’t work, your hypothesis is disproved.

6. Based On Information Source

6.1 primary research.

Characteristics : Self-conducted; could be expensive and time-consuming

Primary research is any kind of systematic investigation where researchers choose to be directly involved in the data collection process instead of relying on already acquired information.

In other words, researchers collect first-hand data from research subjects depending on the context of the research objectives. The data can be collected via interviews, focus groups, surveys, and observation techniques .

With this approach, researchers have full control of the data because they own the data.

Rafael Badziag, an entrepreneur and award-winning author, conducted face-to-face interviews with 21 self-made billionaires to understand the difference between financially successful people (millionaires) and financially super-successful people (billionaires). Based on these in-depth interviews, he wrote a book titled 20 Principles of Billionaire Wealth and Success .

6.2 Secondary Research

Characteristics : Quick; inexpensive; based on data collected from previous studies

Secondary research is based on existing data that has already been analyzed, tested, and filtered. The existing data is collected and summarized to increase the overall effectiveness of the research.

Generally, data is taken from public libraries, websites, already filled-in surveys, textbooks, encyclopedias, government documents, statistical databases, academic papers, and historical records.

Review papers
Books that analyze and interpret a certain topic
Criticism of literature, artworks, or music

Most individuals and small businesses conduct secondary research because results can be obtained faster and more affordably than primary research. These studies vary in credibility depending on where the data is coming from and who is conducting the research.

5 According to the Data Type Used In Research

5.1 qualitative research.

Characteristics : Explores complex human issues; easily adaptable to changes in the research environment

Qualitative research is primarily exploratory research, which means it relies on data obtained from first-hand observations, documents, recordings made in natural settings, artifacts, interviews, and focus groups. The data is non-statistical and unstructured or semi-structured.

In terms of design, qualitative research is flexible and adaptable and can evolve over time. It can also be used to explain the outcome of quantitative research methods.

A study of the perception of college students regarding technology and college readiness.
A study of the psychological impact of unemployment on individuals.

Qualitative researchers dig deep into the topic to gain information about people’s thinking, attitudes, and motivations. They consider themselves “instruments” in research because every analysis and interpretation is filtered through their own personal lens.

Although this type of study brings a depth of understanding to the research questions, sometimes, it makes the results harder to analyze.

5.2 Quantitative Research

Characteristics : Deductive; step-wise; predetermined

Quantitative research is a systematic investigation of gathering and analyzing numerical data. It can be used to identify patterns, test casual relationships, make predictions, and generalize outcomes to wider populations.

There are numerous quantitative approaches that help researchers uncover various types of information on users. For instance, A/B testing is performed on finished products, while surveys are performed throughout the project’s design process.

The results obtained from quantitative research are logical, statistical, and unbiased. They can be generalized to an entire population to take necessary actions for improvement.

Quantitative research into the stock market is used to develop algorithms to exploit investment hypotheses.
Studies that include percentage volumes of all the compounds (gases) mixed in the Earth’s atmosphere.

This type of research is widely used to develop and test theories, models, and hypotheses pertaining to phenomena. It is mostly used in demography, economics, marketing, sociology, psychology, and scientific studies, and less frequently in history and anthropology.

4 How Data Is Collected

4.1 field research.

Characteristics : Expensive to conduct but can yield more detailed data

Field research is a method of collecting raw data outside the workplace setting. Although it is characterized as qualitative research, it often includes quantitative dimensions.

Field research is used in a wide range of disciplines, including biology, economics, sociology, anthropology, and earth and atmospheric sciences. Since researchers get to observe their subjects in their own settings, they can achieve more accurate and detailed data.

Biologists conduct field research to observe how animals interact with their environments.
Geologists collect lava samples to analyze how volcanoes work and predict future eruptions.

It can also be used to uncover information that may not be easily detectable or that researchers may be unaware of.

4.2 Laboratory research

Characteristics : Extraneous variables can be controlled; replication is more feasible

Studies conducted in a facility that provides controlled conditions are called lab research. They are used for testing chemical compounds, performing microbiological, microscopical, and biochemical tests, growing tissues in cultures, and conducting scientific experiments.

Laboratory research can also be described as a tightly controlled investigation in which scientists can manipulate specific factors to determine if such manipulations produce a change in the subject. Also, the subject under investigation can be exposed to customized environments to observe its reaction.

Testing hundreds of thousands of compounds to develop a medicine
Conducting high-energy physics experiments
Running simulations to prove/disprove hypotheses

While lab studies have higher internal validity compared to field research, they tend to be less generalizable to the real world (which means they have less external validity).

4.3 Documentary Research

Characteristics : Inexpensive; useful for hypothesis

Documentary research involves the use of personal or official documents as the source of information. These documents could be anything , ranging from newspapers and statistical publications to maps and diaries.

It’s more like a content analysis that involves exploring existing data recorded in texts, media, and physical forms. The analysis can be either quantitative or qualitative (or both).

This type of research is mostly conducted by social scientists to examine various documents in the interest of historical or social value.

Emile Durkheim, a French sociologist, wrote a book titled Suicide: A Study in Sociology in 1897. It was the first methodological study that used several documents for social research.

Documentary research: Recent study found ~50% of adults sometimes or always feel alone. 40% said their relationships aren’t meaningful and they feel isolated. Dot Connecting: Car dependency contributes to the mental health crisis. Local land use policy needs serious reform. pic.twitter.com/1yLUnboAKv — Andy Boenau (@Boenau) August 24, 2023

3. According to the Extent of Variable Manipulation

3.1 experimental research.

Characteristics : Time-consuming process, but results are specific

Experimental research strictly adheres to a scientific research design. It includes three elements:

A hypothesis
Variables that can be manipulated
Variables that can be calculated, measured, and compared

This type of research is always conducted in a controlled environment. Researchers gather data and test it in a specific manner. The outcomes either support or disprove the hypothesis.

Experimental research can be further grouped into two broad categories:

True experimental research relies on statistical analysis to prove or reject a hypothesis, which makes it the most accurate form of research.
Quasi-experimental research is also known as natural experiments because researchers don’t have complete control over the independent variables. For instance, researchers looking at birth order and personality differences cannot manipulate the independent variable in the situation.

Forensic studies (that examine splatter, decomposition process, and damages to objects) can be conducted precisely in a controlled environment. Another example would be determining several aspects of a product, such as the concentration levels of Ethyl Alcohol within antibacterial hand sanitizers.

3.2 Non-Experimental Research

Characteristics : Relies on correlations, surveys, or case studies

In a non-experimental study, researchers cannot manipulate or control the predictor variable or subjects. Instead, they rely on observation, interpretation, and interactions to draw a conclusion. This means researchers cannot demonstrate a true cause-and-effect relationship.

It is important to note that non-experimental research doesn’t mean nonscientific. The experimenter relies on correlations, case studies, or surveys to come to a conclusion.

Let’s say you want to analyze how violet men and women are in a particular state. In this case, the predictor variable for violence is gender. And since you cannot change this variable (you can’t turn men into women and women into men, back and forth), you need to perform a non-experimental study.

This type of study is conducted when the hypothesis relates to a single variable (how precise are people’s first impressions?) or the research question relates to a non-causal statistical relationship between variables (is there a link between mathematical intelligence and verbal intelligence?).

2. Time-Dependent Studies

2.1 cross-sectional research.

Characteristics : Inexpensive; observational in nature

Cross-sectional research involves analyzing data from a population, or a representative subset, at a specific point in time. The members participating in the research are selected based on certain variables of interest.

Since these studies capture a snapshot of a single moment in time, they may not provide definite information about cause-and-effect relationships. However, they allow researchers to compare several different variables at the same time.

Scientists in healthcare can conduct a cross-sectional study to understand how adults ages 18-35 across London are prone to obesity.
Analysts can conduct cross-sectional research in schools to see how students in the same grade respond to changes in the curriculum.

This type of research is often used in medicine, social science, and developmental psychology. It is mostly used to describe specific characteristics of the population, such as the prevalence of an illness, and to support further research and experimentation.

Mikhail Katsnelson, UrFU graduate and former chief researcher, has entered the top 1% of the world’s most cited researchers in the field of cross-sectional research. The scientist has 1396 publications cited 61114 times (total citations – 94950). https://t.co/lH3fAF8Q31 pic.twitter.com/MBYNjwI0Lf — Ural Federal University (@Ural_Federal) November 24, 2023

2.2 Longitudinal Research

Characteristics : Expensive; takes a longer time, from years to even decades

A longitudinal study is a type of correlational research that involves examining variables over an extended period of time. This means researchers conduct many observations of the same subject over a period of time, sometimes lasting a few decades.

Since scientists can observe changes over time, this type of study can provide unique insights that might not be possible any other way.

Researchers may analyze the changes in cholesterol levels among men over 50 who walk daily for a period of 10 years.
The Harvard Study of Adult Development is one of the world’s longest studies of adult life — researchers have collected vast amounts of data on participants’ physical and mental health for over 80 years.

Although longitudinal studies can provide a wealth of information on a topic, they are expensive and difficult to carry out. They often require many researchers and participants, some of whom may leave the project before its completion.

1. According To Its Purpose

1.1 theoretical research.

Characteristics : Answers “what” and “why” questions without commercial goals

Theoretical research is a logical exploration of a system of beliefs and assumptions. The researchers theorize how a particular system and its environment act under certain conditions and then study the implications of how it is defined.

In general, theoretical research follows an argumentative pattern and is organized around the solution of a problem.

It addresses questions like “What’s the point of the study,” “Why is this topic relevant,” “What has been done in the field so far,” “What are the current problems,” “What solution may be offered,” and “Why is this solution feasible or impractical.”

A case study of graphene research by temporal and geographic analysis
Black holes hint towards De Sitter-Matrix theory

This type of research is important to understand the edge cases, bounds, and emergent behaviors of a system. Since it seeks to answer fundamental questions for the human being, it is common to all areas of knowledge, from chemists, biologists, and engineers to sociologists, philosophers, and historians.

Dear #Researchers #Researchpaper You need theory in designing and preparing your research either theoretical, and conceptual! An excellent place to start is by learning the similarities and differences between these: pic.twitter.com/L9qIarjW1f — Fabrice Dukuzumuremyi (@dukufab1) November 22, 2023

1.2 Applied Research

Characteristics : Targets real-world problems; has specific commercial objectives

Applied research involves using scientific methods and knowledge to solve practical problems that often have an impact on life, health, work, and overall well-being.

In other words, applied research is the practical application of science. It examines and utilizes accumulated theories, techniques, and knowledge for a specific purpose.

Applied research may also use a more provisional conceptual framework, like pillar questions or working hypotheses because it has a provisional close-to-the-data and close-to-the-problem orientation.

In most cases, applied research has specific commercial objectives related to procedures, products, or services.

A company might hire an applied researcher to establish rules or standards for hiring employees that are best suited for specific jobs.
A hospital might conduct applied research to determine the most effective way of preparing patients for certain types of surgical procedures.

One can say that applied research is conducted with the goal of improving human living standards. For instance, researchers may study ways and means to treat a specific disease, increase crop production, improve the energy efficiency of homes or modes of transportation, etc.

Frequently Asked Questions

What’s the purpose of conducting research.

Research is conducted to enhance society by advancing knowledge through the development of ideas, concepts, and theories. A research purpose is met through formulating hypotheses, gathering relevant data, examining results, drawing conclusions, implementing findings into real-world applications, and coming up with new research questions.

From discovering antibiotics to forecasting weather, researchers are constantly discovering new ways to understand the world and how it works — with the ultimate goal of improving human lives.

What are the main characteristics of research?

The following are the most important characteristics of research in any field:

The research must focus on priority problems
It should be systematic and logical
It should be generative and action-oriented
Findings of one researcher should be made available to other researchers

What is market research?

Market research is conducted directly with potential customers to determine the viability of a new product or service. It is either conducted by companies or outsourced to agencies that have expertise in the process. It can be done through focus groups, surveys, or product testing.

The research allows companies and businesses to discover their target market and get feedback from customers about their interest in the product or service. It provides a wealth of information about the customers’ needs and demands, which helps businesses plan and strategize accordingly.

What’s the difference between qualitative and quantitative research?

While qualitative research involves exploring and interpreting non-numerical data (such as narratives, interviews, and observations) to understand the depth and nuances of a phenomenon, quantitative research utilizes numerical data and statistical techniques to test hypotheses, identify patterns, and draw objective conclusions.

How to conduct accurate and effective research?

Conducting quality research is a systematic process, which involves various steps:

Define a research question and judge the scope of the project
Find all possible sources of information
Synthesize, analyze, and integrate prior knowledge
Select the most appropriate investigation methods and research tools
Devise and carry out an experiment yourself
Report research findings and test them in real-world (if applicable)

If you are writing an academic paper, explain how you analyzed data and minimized the impact of any unexpected obstacles. Preempt major critiques of your methodology and show that you made the research as rigorous as possible. And don’t forget to give credit where credit is due; cite your sources properly.

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Varun Kumar

I am a professional technology and business research analyst with more than a decade of experience in the field. My main areas of expertise include software technologies, business strategies, competitive analysis, and staying up-to-date with market trends.

I hold a Master's degree in computer science from GGSIPU University. If you'd like to learn more about my latest projects and insights, please don't hesitate to reach out to me via email at [email protected] .

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Research Methods Help Guide

Quick Glossary
Types of Data
Types of Research

Introduction

Case report, case control study, cohort study, randomized controlled trial, practice guideline, systematic review, meta-analysis.

Helpful Resources
Get Help @ FIU

Study Designs

Other Resources

Nursing Resources: Types of Studies LibGuide created by the Ebling Library, Health Sciences Learning Center at the University of Wisconsin-Madison.

Database Guides

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All definitions on this page are from the Study Design 101 tutorial created by the Himmelfarb Health Sciences Library . Go to the tutorial for much more information, examples, and self-assessments.

Use the resources located below each definition to find studies of that type in library databases and other resources. Hover over the database/resource name for information on applicable filters, limits, subjects, etc.

Note: although filters, limits, subjects, and other database options will help you focus your results to certain study types, rely on your own judgment when determining if a study matches the type you are seeking.

An article that describes and interprets an individual case, often written in the form of a detailed story.

More Information

Find case reports in:

A study that compares patients who have a disease or outcome of interest (cases) with patients who do not have the disease or outcome (controls), and looks back retrospectively to compare how frequently the exposure to a risk factor is present in each group to determine the relationship between the risk factor and the disease.

Find case control studies in:

A study design where one or more samples (called cohorts) are followed prospectively and subsequent status evaluations with respect to a disease or outcome are conducted to determine which initial participants exposure characteristics (risk factors) are associated with it. As the study is conducted, outcome from participants in each cohort is measured and relationships with specific characteristics determined.

Find cohort studies in:

A study design that randomly assigns participants into an experimental group or a control group. As the study is conducted, the only expected difference between the control and experimental groups in a randomized controlled trial (RCT) is the outcome variable being studied.

Find randomized controlled trials in:

A statement produced by a panel of experts that outlines current best practice to inform health care professionals and patients in making clinical decisions. The statement is produced after an extensive review of the literature and is typically created by professional associations, government agencies, and/or public or private organizations.

Find practice guidelines in:

A document often written by a panel that provides a comprehensive review of all relevant studies on a particular clinical or health-related topic/question. The systematic review is created after reviewing and combining all the information from both published and unpublished studies (focusing on clinical trials of similar treatments) and then summarizing the findings.

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A subset of systematic reviews; a method for systematically combining pertinent qualitative and quantitative study data from several selected studies to develop a single conclusion that has greater statistical power. This conclusion is statistically stronger than the analysis of any single study, due to increased numbers of subjects, greater diversity among subjects, or accumulated effects and results.

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Dtsch Arztebl Int
v.106(15); 2009 Apr

Types of Study in Medical Research

Bernd röhrig.

1 MDK Rheinland-Pfalz, Referat Rehabilitation/Biometrie, Alzey

Jean-Baptist du Prel

2 Zentrum für Präventive Pädiatrie, Zentrum für Kinder- und Jugendmedizin, Mainz

Daniel Wachtlin

3 Interdisziplinäres Zentrum Klinische Studien (IZKS), Fachbereich Medizin der Universität Mainz

Maria Blettner

4 Institut für Medizinische Biometrie, Epidemiologie und Informatik (IMBEI), Johannes Gutenberg Universität Mainz

The choice of study type is an important aspect of the design of medical studies. The study design and consequent study type are major determinants of a study’s scientific quality and clinical value.

This article describes the structured classification of studies into two types, primary and secondary, as well as a further subclassification of studies of primary type. This is done on the basis of a selective literature search concerning study types in medical research, in addition to the authors’ own experience.

Three main areas of medical research can be distinguished by study type: basic (experimental), clinical, and epidemiological research. Furthermore, clinical and epidemiological studies can be further subclassified as either interventional or noninterventional.

Conclusions

The study type that can best answer the particular research question at hand must be determined not only on a purely scientific basis, but also in view of the available financial resources, staffing, and practical feasibility (organization, medical prerequisites, number of patients, etc.).

The quality, reliability and possibility of publishing a study are decisively influenced by the selection of a proper study design. The study type is a component of the study design (see the article "Study Design in Medical Research") and must be specified before the study starts. The study type is determined by the question to be answered and decides how useful a scientific study is and how well it can be interpreted. If the wrong study type has been selected, this cannot be rectified once the study has started.

After an earlier publication dealing with aspects of study design, the present article deals with study types in primary and secondary research. The article focuses on study types in primary research. A special article will be devoted to study types in secondary research, such as meta-analyses and reviews. This article covers the classification of individual study types. The conception, implementation, advantages, disadvantages and possibilities of using the different study types are illustrated by examples. The article is based on a selective literature research on study types in medical research, as well as the authors’ own experience.

Classification of study types

In principle, medical research is classified into primary and secondary research. While secondary research summarizes available studies in the form of reviews and meta-analyses, the actual studies are performed in primary research. Three main areas are distinguished: basic medical research, clinical research, and epidemiological research. In individual cases, it may be difficult to classify individual studies to one of these three main categories or to the subcategories. In the interests of clarity and to avoid excessive length, the authors will dispense with discussing special areas of research, such as health services research, quality assurance, or clinical epidemiology. Figure 1 gives an overview of the different study types in medical research.

An external file that holds a picture, illustration, etc.
Object name is Dtsch_Arztebl_Int-106-0262_001.jpg

Classification of different study types

*1 , sometimes known as experimental research; *2 , analogous term: interventional; *3 , analogous term: noninterventional or nonexperimental

This scheme is intended to classify the study types as clearly as possible. In the interests of clarity, we have excluded clinical epidemiology — a subject which borders on both clinical and epidemiological research ( 3 ). The study types in this area can be found under clinical research and epidemiology.

Basic research

Basic medical research (otherwise known as experimental research) includes animal experiments, cell studies, biochemical, genetic and physiological investigations, and studies on the properties of drugs and materials. In almost all experiments, at least one independent variable is varied and the effects on the dependent variable are investigated. The procedure and the experimental design can be precisely specified and implemented ( 1 ). For example, the population, number of groups, case numbers, treatments and dosages can be exactly specified. It is also important that confounding factors should be specifically controlled or reduced. In experiments, specific hypotheses are investigated and causal statements are made. High internal validity (= unambiguity) is achieved by setting up standardized experimental conditions, with low variability in the units of observation (for example, cells, animals or materials). External validity is a more difficult issue. Laboratory conditions cannot always be directly transferred to normal clinical practice and processes in isolated cells or in animals are not equivalent to those in man (= generalizability) ( 2 ).

Basic research also includes the development and improvement of analytical procedures—such as analytical determination of enzymes, markers or genes—, imaging procedures—such as computed tomography or magnetic resonance imaging—, and gene sequencing—such as the link between eye color and specific gene sequences. The development of biometric procedures—such as statistical test procedures, modeling and statistical evaluation strategies—also belongs here.

Clinical studies

Clinical studies include both interventional (or experimental) studies and noninterventional (or observational) studies. A clinical drug study is an interventional clinical study, defined according to §4 Paragraph 23 of the Medicines Act [Arzneimittelgesetz; AMG] as "any study performed on man with the purpose of studying or demonstrating the clinical or pharmacological effects of drugs, to establish side effects, or to investigate absorption, distribution, metabolism or elimination, with the aim of providing clear evidence of the efficacy or safety of the drug."

Interventional studies also include studies on medical devices and studies in which surgical, physical or psychotherapeutic procedures are examined. In contrast to clinical studies, §4 Paragraph 23 of the AMG describes noninterventional studies as follows: "A noninterventional study is a study in the context of which knowledge from the treatment of persons with drugs in accordance with the instructions for use specified in their registration is analyzed using epidemiological methods. The diagnosis, treatment and monitoring are not performed according to a previously specified study protocol, but exclusively according to medical practice."

The aim of an interventional clinical study is to compare treatment procedures within a patient population, which should exhibit as few as possible internal differences, apart from the treatment ( 4 , e1 ). This is to be achieved by appropriate measures, particularly by random allocation of the patients to the groups, thus avoiding bias in the result. Possible therapies include a drug, an operation, the therapeutic use of a medical device such as a stent, or physiotherapy, acupuncture, psychosocial intervention, rehabilitation measures, training or diet. Vaccine studies also count as interventional studies in Germany and are performed as clinical studies according to the AMG.

Interventional clinical studies are subject to a variety of legal and ethical requirements, including the Medicines Act and the Law on Medical Devices. Studies with medical devices must be registered by the responsible authorities, who must also approve studies with drugs. Drug studies also require a favorable ruling from the responsible ethics committee. A study must be performed in accordance with the binding rules of Good Clinical Practice (GCP) ( 5 , e2 – e4 ). For clinical studies on persons capable of giving consent, it is absolutely essential that the patient should sign a declaration of consent (informed consent) ( e2 ). A control group is included in most clinical studies. This group receives another treatment regimen and/or placebo—a therapy without substantial efficacy. The selection of the control group must not only be ethically defensible, but also be suitable for answering the most important questions in the study ( e5 ).

Clinical studies should ideally include randomization, in which the patients are allocated by chance to the therapy arms. This procedure is performed with random numbers or computer algorithms ( 6 – 8 ). Randomization ensures that the patients will be allocated to the different groups in a balanced manner and that possible confounding factors—such as risk factors, comorbidities and genetic variabilities—will be distributed by chance between the groups (structural equivalence) ( 9 , 10 ). Randomization is intended to maximize homogeneity between the groups and prevent, for example, a specific therapy being reserved for patients with a particularly favorable prognosis (such as young patients in good physical condition) ( 11 ).

Blinding is another suitable method to avoid bias. A distinction is made between single and double blinding. With single blinding, the patient is unaware which treatment he is receiving, while, with double blinding, neither the patient nor the investigator knows which treatment is planned. Blinding the patient and investigator excludes possible subjective (even subconscious) influences on the evaluation of a specific therapy (e.g. drug administration versus placebo). Thus, double blinding ensures that the patient or therapy groups are both handled and observed in the same manner. The highest possible degree of blinding should always be selected. The study statistician should also remain blinded until the details of the evaluation have finally been specified.

A well designed clinical study must also include case number planning. This ensures that the assumed therapeutic effect can be recognized as such, with a previously specified statistical probability (statistical power) ( 4 , 6 , 12 ).

It is important for the performance of a clinical trial that it should be carefully planned and that the exact clinical details and methods should be specified in the study protocol ( 13 ). It is, however, also important that the implementation of the study according to the protocol, as well as data collection, must be monitored. For a first class study, data quality must be ensured by double data entry, programming plausibility tests, and evaluation by a biometrician. International recommendations for the reporting of randomized clinical studies can be found in the CONSORT statement (Consolidated Standards of Reporting Trials, www.consort-statement.org ) ( 14 ). Many journals make this an essential condition for publication.

For all the methodological reasons mentioned above and for ethical reasons, the randomized controlled and blinded clinical trial with case number planning is accepted as the gold standard for testing the efficacy and safety of therapies or drugs ( 4 , e1 , 15 ).

In contrast, noninterventional clinical studies (NIS) are patient-related observational studies, in which patients are given an individually specified therapy. The responsible physician specifies the therapy on the basis of the medical diagnosis and the patient’s wishes. NIS include noninterventional therapeutic studies, prognostic studies, observational drug studies, secondary data analyses, case series and single case analyses ( 13 , 16 ). Similarly to clinical studies, noninterventional therapy studies include comparison between therapies; however, the treatment is exclusively according to the physician’s discretion. The evaluation is often retrospective. Prognostic studies examine the influence of prognostic factors (such as tumor stage, functional state, or body mass index) on the further course of a disease. Diagnostic studies are another class of observational studies, in which either the quality of a diagnostic method is compared to an established method (ideally a gold standard), or an investigator is compared with one or several other investigators (inter-rater comparison) or with himself at different time points (intra-rater comparison) ( e1 ). If an event is very rare (such as a rare disease or an individual course of treatment), a single-case study, or a case series, are possibilities. A case series is a study on a larger patient group with a specific disease. For example, after the discovery of the AIDS virus, the Center for Disease Control (CDC) in the USA collected a case series of 1000 patients, in order to study frequent complications of this infection. The lack of a control group is a disadvantage of case series. For this reason, case series are primarily used for descriptive purposes ( 3 ).

Epidemiological studies

The main point of interest in epidemiological studies is to investigate the distribution and historical changes in the frequency of diseases and the causes for these. Analogously to clinical studies, a distinction is made between experimental and observational epidemiological studies ( 16 , 17 ).

Interventional studies are experimental in character and are further subdivided into field studies (sample from an area, such as a large region or a country) and group studies (sample from a specific group, such as a specific social or ethnic group). One example was the investigation of the iodine supplementation of cooking salt to prevent cretinism in a region with iodine deficiency. On the other hand, many interventions are unsuitable for randomized intervention studies, for ethical, social or political reasons, as the exposure may be harmful to the subjects ( 17 ).

Observational epidemiological studies can be further subdivided into cohort studies (follow-up studies), case control studies, cross-sectional studies (prevalence studies), and ecological studies (correlation studies or studies with aggregated data).

In contrast, studies with only descriptive evaluation are restricted to a simple depiction of the frequency (incidence and prevalence) and distribution of a disease within a population. The objective of the description may also be the regular recording of information (monitoring, surveillance). Registry data are also suited for the description of prevalence and incidence; for example, they are used for national health reports in Germany.

In the simplest case, cohort studies involve the observation of two healthy groups of subjects over time. One group is exposed to a specific substance (for example, workers in a chemical factory) and the other is not exposed. It is recorded prospectively (into the future) how often a specific disease (such as lung cancer) occurs in the two groups ( figure 2a ). The incidence for the occurrence of the disease can be determined for both groups. Moreover, the relative risk (quotient of the incidence rates) is a very important statistical parameter which can be calculated in cohort studies. For rare types of exposure, the general population can be used as controls ( e6 ). All evaluations naturally consider the age and gender distributions in the corresponding cohorts. The objective of cohort studies is to record detailed information on the exposure and on confounding factors, such as the duration of employment, the maximum and the cumulated exposure. One well known cohort study is the British Doctors Study, which prospectively examined the effect of smoking on mortality among British doctors over a period of decades ( e7 ). Cohort studies are well suited for detecting causal connections between exposure and the development of disease. On the other hand, cohort studies often demand a great deal of time, organization, and money. So-called historical cohort studies represent a special case. In this case, all data on exposure and effect (illness) are already available at the start of the study and are analyzed retrospectively. For example, studies of this sort are used to investigate occupational forms of cancer. They are usually cheaper ( 16 ).

An external file that holds a picture, illustration, etc.
Object name is Dtsch_Arztebl_Int-106-0262_002.jpg

Graphical depiction of a prospective cohort study (simplest case [2a]) and a retrospective case control study (2b)

In case control studies, cases are compared with controls. Cases are persons who fall ill from the disease in question. Controls are persons who are not ill, but are otherwise comparable to the cases. A retrospective analysis is performed to establish to what extent persons in the case and control groups were exposed ( figure 2b ). Possible exposure factors include smoking, nutrition and pollutant load. Care should be taken that the intensity and duration of the exposure is analyzed as carefully and in as detailed a manner as possible. If it is observed that ill people are more often exposed than healthy people, it may be concluded that there is a link between the illness and the risk factor. In case control studies, the most important statistical parameter is the odds ratio. Case control studies usually require less time and fewer resources than cohort studies ( 16 ). The disadvantage of case control studies is that the incidence rate (rate of new cases) cannot be calculated. There is also a great risk of bias from the selection of the study population ("selection bias") and from faulty recall ("recall bias") (see too the article "Avoiding Bias in Observational Studies"). Table 1 presents an overview of possible types of epidemiological study ( e8 ). Table 2 summarizes the advantages and disadvantages of observational studies ( 16 ).

1 = slight; 2 = moderate; 3 = high; N/A, not applicable.

*Individual cases may deviate from this pattern.

Selecting the correct study type is an important aspect of study design (see "Study Design in Medical Research" in volume 11/2009). However, the scientific questions can only be correctly answered if the study is planned and performed at a qualitatively high level ( e9 ). It is very important to consider or even eliminate possible interfering factors (or confounders), as otherwise the result cannot be adequately interpreted. Confounders are characteristics which influence the target parameters. Although this influence is not of primary interest, it can interfere with the connection between the target parameter and the factors that are of interest. The influence of confounders can be minimized or eliminated by standardizing the procedure, stratification ( 18 ), or adjustment ( 19 ).

The decision as to which study type is suitable to answer a specific primary research question must be based not only on scientific considerations, but also on issues related to resources (personnel and finances), hospital capacity, and practicability. Many epidemiological studies can only be implemented if there is access to registry data. The demands for planning, implementation, and statistical evaluation for observational studies should be just as high for observational studies as for experimental studies. There are particularly strict requirements, with legally based regulations (such as the Medicines Act and Good Clinical Practice), for the planning, implementation, and evaluation of clinical studies. A study protocol must be prepared for both interventional and noninterventional studies ( 6 , 13 ). The study protocol must contain information on the conditions, question to be answered (objective), the methods of measurement, the implementation, organization, study population, data management, case number planning, the biometric evaluation, and the clinical relevance of the question to be answered ( 13 ).

Important and justified ethical considerations may restrict studies with optimal scientific and statistical features. A randomized intervention study under strictly controlled conditions of the effect of exposure to harmful factors (such as smoking, radiation, or a fatty diet) is not possible and not permissible for ethical reasons. Observational studies are a possible alternative to interventional studies, even though observational studies are less reliable and less easy to control ( 17 ).

A medical study should always be published in a peer reviewed journal. Depending on the study type, there are recommendations and checklists for presenting the results. For example, these may include a description of the population, the procedure for missing values and confounders, and information on statistical parameters. Recommendations and guidelines are available for clinical studies ( 14 , 20 , e10 , e11 ), for diagnostic studies ( 21 , 22 , e12 ), and for epidemiological studies ( 23 , e13 ). Since 2004, the WHO has demanded that studies should be registered in a public registry, such as www.controlled-trials.com or www.clinicaltrials.gov . This demand is supported by the International Committee of Medical Journal Editors (ICMJE) ( 24 ), which specifies that the registration of the study before inclusion of the first subject is an essential condition for the publication of the study results ( e14 ).

When specifying the study type and study design for medical studies, it is essential to collaborate with an experienced biometrician. The quality and reliability of the study can be decisively improved if all important details are planned together ( 12 , 25 ).

Acknowledgments

Translated from the original German by Rodney A. Yeates, M.A., Ph.D.

Conflict of interest statement

The authors declare that there is no conflict of interest in the sense of the International Committee of Medical Journal Editors.

Type Of Academic Writing: A Guide for Every Student

Think of academic writing like a large toolbox with different tools, each meant for a specific task. Just like you wouldn’t use a hammer to fix a leaky faucet, you don’t use the same writing style for every academic task. Whether you’re a high school student, a college undergrad, or a graduate researcher, understanding the type of academic writing can make a world of difference in your studies. So, let’s dive into this toolbox and explore the various writing styles you’ll encounter on your academic journey.

What Is Academic Writing And Examples?

Table of Contents

Academic writing is a fancy way of writing that’s used in schools and colleges. Its goal is to share information and ideas clearly and neatly. It’s common in schools, colleges, universities, and academic research. Here are some examples of academic writing:

Research Papers: Detailed studies on specific topics, presenting findings and analysis.
Essays: Structured pieces of writing with a clear thesis statement and supporting evidence.
Literature Reviews: Summaries and evaluations of existing research on a particular topic.
Case Studies: In-depth examinations of a specific situation or individual, often in psychology or sociology.
Theses and Dissertations: Extensive research projects culminating in a formal document for advanced degrees.
Reports: Formal documents presenting facts, analyses, and recommendations.
Annotated Bibliographies: Lists of sources with brief summaries and evaluations.
Lab Reports: Documents detailing scientific experiments and their results.

Each of these examples follows specific conventions of academic writing, such as citing sources, using formal language, and adhering to a particular structure.

What Are The 4 Main Types Of Academic Writing?

Descriptive writing, what is it.

Descriptive writing paints a vivid picture with words. Its goal is to describe a person, place, event, or object in detail, allowing readers to visualize it in their minds.

Characteristics

Rich in sensory details: Descriptive writing appeals to the senses—sight, sound, touch, taste, and smell.
Use of vivid language: It employs colorful adjectives and adverbs to create a clear image.
Objective observation: Descriptive writing sticks to the facts without interpretation.
Scientific Observations: Think of a biologist describing the behavior of ants in intricate detail.
Literary Analysis: When an English student dissects the imagery in a poem, that’s descriptive writing in action.

Analytical Writing

Analytical writing involves breaking down complex ideas into smaller parts to understand them better. It’s about examining something closely and drawing connections.

Critical thinking: Analytical writing requires you to analyze, evaluate, and interpret information.
Comparison and contrast: Often involves comparing multiple viewpoints or pieces of literature.
Logical structure: Ideas are presented in a logical sequence with supporting evidence.
Critical Reviews: Movie critics use analytical writing to assess films, discussing what worked and what didn’t.
Comparative Essays: Comparing two historical events or two theories in psychology falls under analytical writing.

Persuasive Writing

Persuasive writing aims to convince readers of a particular viewpoint or idea. It’s about presenting arguments and supporting them with evidence.

Clear thesis statement: The writer states their position early on.
Appeals to emotions and logic: Persuasive writing uses both emotional and logical appeals to sway the reader.
Counter Arguments addressed: Acknowledges opposing views and refutes them.
Argumentative Essays: These essays argue a specific point, such as the importance of recycling or the benefits of a vegan diet.
Position Papers: When a politician writes a paper advocating for a new law, that’s persuasive writing in action.

Expository Writing

Expository writing is all about explaining and informing. It’s like being a tour guide for your reader, leading them through a topic step by step.

Clarity and conciseness: Expository writing is straightforward and to the point.
Research-based: Relies on credible sources to support the information presented.
Instructional tone: Often includes “how-to” guides or explanations of processes.
Research Papers: When a scientist explains their findings and their implications, that’s expository writing.
How-to Guides: Cooking recipes, DIY instructions, and academic guides on formatting papers are all examples of expository writing.

Narrative Writing

Narrative writing tells a story. It can be personal, fictional, or based on real events, but its essence lies in engaging the reader in a narrative arc.

Characters and plot: Narrative writing involves characters with goals and obstacles.
Chronological structure: Stories are often told in sequence, from beginning to end.
Descriptive elements: Like descriptive writing, narratives use vivid details to immerse the reader.
Personal Essays: Reflective pieces where the writer shares a personal experience and its significance.
Case Studies: In fields like psychology and sociology, researchers use narrative writing to present detailed case studies of individuals.

What Are The 6 Common Problems In Academic Writing?

In academic writing, several common problems can arise, leading to challenges in clarity, coherence, and overall effectiveness of the work. Here are six common problems encountered in academic writing:

Lack of Clarity and Precision
Issue: Unclear or vague writing can confuse readers and weaken the argument.
Solution: Define terms, use specific examples, and ensure each sentence contributes to the main point.
Poor Organization and Structure
Issue: Disorganized writing makes it difficult for readers to follow the flow of ideas.
Solution: Use clear introductions, topic sentences, and transitions between paragraphs to create a logical structure.
Weak Thesis Statements
Issue: A weak thesis can result in a lack of focus and direction in the paper.
Solution: Craft a strong, clear thesis that presents the main argument or purpose of the paper.
Issue: Using someone else’s ideas, words, or work without proper citation.
Solution: Always give credit to sources through proper citation and paraphrasing, and understand when to quote directly.
Inadequate Research
Issue: Insufficient or unreliable sources can weaken the credibility of the work.
Solution: Conduct thorough research using credible sources and critically evaluate the information.
Grammar and Punctuation Errors
Issue: Mistakes in grammar, punctuation, and spelling can distract from the message.
Solution: Proofread carefully, use grammar guides, and consider seeking feedback from peers or instructors.

What Is The Best Way To Learn Academic Writing?

Learning academic writing is a skill that improves with practice and guidance. Here are some steps to help you master academic writing:

Understand the Basics
Familiarize yourself with the different types of academic writing: descriptive, analytical, persuasive, expository, and narrative.
Learn about academic style guides (e.g., APA, MLA, Chicago) for formatting, citations, and references.
Read Academic Writing
Read widely in your field of study to understand the style and structure of academic writing.
Analyze how successful academic writers present their arguments, use evidence, and structure their work.
Practice Regularly
Start with simple exercises, such as summarizing articles or writing short essays.
Gradually tackle more complex tasks, such as research papers or critical analyses.
Seek Feedback
Share your writing with peers, professors, or writing centers for constructive feedback.
Use feedback to identify areas for improvement and refine your skills.
Master Citations and References
Learn how to properly cite sources according to the style guide used in your discipline.
Understand the differences between paraphrasing, summarizing, and quoting sources.
Focus on Clarity and Coherence
Ensure your writing is clear, concise, and logically organized.
Use topic sentences, transitions, and signposts to guide the reader through your argument.
Edit and Revise
Edit for grammar, punctuation, and spelling errors.
Revise for clarity, coherence, and strengthening of arguments.
Utilize Writing Resources
Take advantage of writing workshops, online resources, and style guides.
Consider using writing software or apps to help with grammar checking and organization.
Stay Persistent and Patient
Academic writing is a skill that takes time to develop.
Don’t get discouraged by challenges; view them as opportunities to improve.
Immerse Yourself in Academic Discourse
Engage in discussions, seminars, and conferences related to your field.
Participate in writing groups or forums where you can discuss and learn from others.

Conclusion: Type Of Academic Writing

Understanding the type of academic writing is like having a versatile set of tools in your writing toolbox. Whether you’re crafting a research paper, arguing a point, or telling a story, choosing the right style enhances your message. So, next time you’re faced with an academic task, consider which tool—descriptive, analytical, persuasive, expository, or narrative—best suits the job. Happy writing!

In this journey through the world of academic writing, we’ve explored the purpose, characteristics, and examples of each type. Armed with this knowledge, you’re better equipped to tackle various assignments with confidence. Remember, the key to mastery is practice, so don’t hesitate to experiment with these styles in your own writing. Here’s to your success in the diverse landscape of academic writing!

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Black Americans Have a Clear Vision for Reducing Racism but Little Hope It Will Happen

Many say key U.S. institutions should be rebuilt to ensure fair treatment

Table of contents.

Black Americans see little improvement in their lives despite increased national attention to racial issues
Few Black adults expect equality for Black people in the U.S.
Black adults say racism and police brutality are extremely big problems for Black people in the U.S.
Personal experiences with discrimination are widespread among Black Americans
Black adults see voting as the most effective strategy for moving toward equality in the U.S.
Some Black adults see Black businesses and communities as effective remedies for inequality
Black Americans say race matters little when choosing political allies
The legacy of slavery affects Black Americans today
Most Black adults agree the descendants of enslaved people should be repaid
The types of repayment Black adults think would be most helpful
Responsibility for reparations and the likelihood repayment will occur
Black adults say the criminal justice system needs to be completely rebuilt
Black adults say political, economic and health care systems need major changes to ensure fair treatment
Most Black adults say funding for police departments should stay the same or increase
Acknowledgments
Appendix: Supplemental tables
The American Trends Panel survey methodology

Photo showing visitors at the Martin Luther King Jr. Memorial in Washington, D.C. (Astrid Riecken/picture alliance via Getty Images)

Pew Research Center conducted this analysis to understand the nuances among Black people on issues of racial inequality and social change in the United States. This in-depth survey explores differences among Black Americans in their views on the social status of the Black population in the U.S.; their assessments of racial inequality; their visions for institutional and social change; and their outlook on the chances that these improvements will be made. The analysis is the latest in the Center’s series of in-depth surveys of public opinion among Black Americans (read the first, “ Faith Among Black Americans ” and “ Race Is Central to Identity for Black Americans and Affects How They Connect With Each Other ”).

The online survey of 3,912 Black U.S. adults was conducted Oct. 4-17, 2021. Black U.S. adults include those who are single-race, non-Hispanic Black Americans; multiracial non-Hispanic Black Americans; and adults who indicate they are Black and Hispanic. The survey includes 1,025 Black adults on Pew Research Center’s American Trends Panel (ATP) and 2,887 Black adults on Ipsos’ KnowledgePanel. Respondents on both panels are recruited through national, random sampling of residential addresses.

Recruiting panelists by phone or mail ensures that nearly all U.S. Black adults have a chance of selection. This gives us confidence that any sample can represent the whole population (see our Methods 101 explainer on random sampling). Here are the questions used for the survey of Black adults, along with its responses and methodology .

The terms “Black Americans,” “Black people” and “Black adults” are used interchangeably throughout this report to refer to U.S. adults who self-identify as Black, either alone or in combination with other races or Hispanic identity.

Throughout this report, “Black, non-Hispanic” respondents are those who identify as single-race Black and say they have no Hispanic background. “Black Hispanic” respondents are those who identify as Black and say they have Hispanic background. We use the terms “Black Hispanic” and “Hispanic Black” interchangeably. “Multiracial” respondents are those who indicate two or more racial backgrounds (one of which is Black) and say they are not Hispanic.

Respondents were asked a question about how important being Black was to how they think about themselves. In this report, we use the term “being Black” when referencing responses to this question.

In this report, “immigrant” refers to people who were not U.S. citizens at birth – in other words, those born outside the U.S., Puerto Rico or other U.S. territories to parents who were not U.S. citizens. We use the terms “immigrant,” “born abroad” and “foreign-born” interchangeably.

Throughout this report, “Democrats and Democratic leaners” and just “Democrats” both refer to respondents who identify politically with the Democratic Party or who are independent or some other party but lean toward the Democratic Party. “Republicans and Republican leaners” and just “Republicans” both refer to respondents who identify politically with the Republican Party or are independent or some other party but lean toward the Republican Party.

Respondents were asked a question about their voter registration status. In this report, respondents are considered registered to vote if they self-report being absolutely certain they are registered at their current address. Respondents are considered not registered to vote if they report not being registered or express uncertainty about their registration.

To create the upper-, middle- and lower-income tiers, respondents’ 2020 family incomes were adjusted for differences in purchasing power by geographic region and household size. Respondents were then placed into income tiers: “Middle income” is defined as two-thirds to double the median annual income for the entire survey sample. “Lower income” falls below that range, and “upper income” lies above it. For more information about how the income tiers were created, read the methodology .

Bar chart showing after George Floyd’s murder, half of Black Americans expected policy changes to address racial inequality, After George Floyd’s murder, half of Black Americans expected policy changes to address racial inequality

More than a year after the murder of George Floyd and the national protests, debate and political promises that ensued, 65% of Black Americans say the increased national attention on racial inequality has not led to changes that improved their lives. 1 And 44% say equality for Black people in the United States is not likely to be achieved, according to newly released findings from an October 2021 survey of Black Americans by Pew Research Center.

This is somewhat of a reversal in views from September 2020, when half of Black adults said the increased national focus on issues of race would lead to major policy changes to address racial inequality in the country and 56% expected changes that would make their lives better.

At the same time, many Black Americans are concerned about racial discrimination and its impact. Roughly eight-in-ten say they have personally experienced discrimination because of their race or ethnicity (79%), and most also say discrimination is the main reason many Black people cannot get ahead (68%).

Even so, Black Americans have a clear vision for how to achieve change when it comes to racial inequality. This includes support for significant reforms to or complete overhauls of several U.S. institutions to ensure fair treatment, particularly the criminal justice system; political engagement, primarily in the form of voting; support for Black businesses to advance Black communities; and reparations in the forms of educational, business and homeownership assistance. Yet alongside their assessments of inequality and ideas about progress exists pessimism about whether U.S. society and its institutions will change in ways that would reduce racism.

These findings emerge from an extensive Pew Research Center survey of 3,912 Black Americans conducted online Oct. 4-17, 2021. The survey explores how Black Americans assess their position in U.S. society and their ideas about social change. Overall, Black Americans are clear on what they think the problems are facing the country and how to remedy them. However, they are skeptical that meaningful changes will take place in their lifetime.

Black Americans see racism in our laws as a big problem and discrimination as a roadblock to progress

Bar chart showing about six-in-ten Black adults say racism and police brutality are extremely big problems for Black people in the U.S. today

Black adults were asked in the survey to assess the current nature of racism in the United States and whether structural or individual sources of this racism are a bigger problem for Black people. About half of Black adults (52%) say racism in our laws is a bigger problem than racism by individual people, while four-in-ten (43%) say acts of racism committed by individual people is the bigger problem. Only 3% of Black adults say that Black people do not experience discrimination in the U.S. today.

In assessing the magnitude of problems that they face, the majority of Black Americans say racism (63%), police brutality (60%) and economic inequality (54%) are extremely or very big problems for Black people living in the U.S. Slightly smaller shares say the same about the affordability of health care (47%), limitations on voting (46%), and the quality of K-12 schools (40%).

Aside from their critiques of U.S. institutions, Black adults also feel the impact of racial inequality personally. Most Black adults say they occasionally or frequently experience unfair treatment because of their race or ethnicity (79%), and two-thirds (68%) cite racial discrimination as the main reason many Black people cannot get ahead today.

Black Americans’ views on reducing racial inequality

Bar chart showing many Black adults say institutional overhauls are necessary to ensure fair treatment

Black Americans are clear on the challenges they face because of racism. They are also clear on the solutions. These range from overhauls of policing practices and the criminal justice system to civic engagement and reparations to descendants of people enslaved in the United States.

Changing U.S. institutions such as policing, courts and prison systems

About nine-in-ten Black adults say multiple aspects of the criminal justice system need some kind of change (minor, major or a complete overhaul) to ensure fair treatment, with nearly all saying so about policing (95%), the courts and judicial process (95%), and the prison system (94%).

Roughly half of Black adults say policing (49%), the courts and judicial process (48%), and the prison system (54%) need to be completely rebuilt for Black people to be treated fairly. Smaller shares say the same about the political system (42%), the economic system (37%) and the health care system (34%), according to the October survey.

While Black Americans are in favor of significant changes to policing, most want spending on police departments in their communities to stay the same (39%) or increase (35%). A little more than one-in-five (23%) think spending on police departments in their area should be decreased.

Black adults who favor decreases in police spending are most likely to name medical, mental health and social services (40%) as the top priority for those reappropriated funds. Smaller shares say K-12 schools (25%), roads, water systems and other infrastructure (12%), and reducing taxes (13%) should be the top priority.

Voting and ‘buying Black’ viewed as important strategies for Black community advancement

Black Americans also have clear views on the types of political and civic engagement they believe will move Black communities forward. About six-in-ten Black adults say voting (63%) and supporting Black businesses or “buying Black” (58%) are extremely or very effective strategies for moving Black people toward equality in the U.S. Smaller though still significant shares say the same about volunteering with organizations dedicated to Black equality (48%), protesting (42%) and contacting elected officials (40%).

Black adults were also asked about the effectiveness of Black economic and political independence in moving them toward equality. About four-in-ten (39%) say Black ownership of all businesses in Black neighborhoods would be an extremely or very effective strategy for moving toward racial equality, while roughly three-in-ten (31%) say the same about establishing a national Black political party. And about a quarter of Black adults (27%) say having Black neighborhoods governed entirely by Black elected officials would be extremely or very effective in moving Black people toward equality.

Most Black Americans support repayment for slavery

Discussions about atonement for slavery predate the founding of the United States. As early as 1672 , Quaker abolitionists advocated for enslaved people to be paid for their labor once they were free. And in recent years, some U.S. cities and institutions have implemented reparations policies to do just that.

Most Black Americans say the legacy of slavery affects the position of Black people in the U.S. either a great deal (55%) or a fair amount (30%), according to the survey. And roughly three-quarters (77%) say descendants of people enslaved in the U.S. should be repaid in some way.

Black adults who say descendants of the enslaved should be repaid support doing so in different ways. About eight-in-ten say repayment in the forms of educational scholarships (80%), financial assistance for starting or improving a business (77%), and financial assistance for buying or remodeling a home (76%) would be extremely or very helpful. A slightly smaller share (69%) say cash payments would be extremely or very helpful forms of repayment for the descendants of enslaved people.

Where the responsibility for repayment lies is also clear for Black Americans. Among those who say the descendants of enslaved people should be repaid, 81% say the U.S. federal government should have all or most of the responsibility for repayment. About three-quarters (76%) say businesses and banks that profited from slavery should bear all or most of the responsibility for repayment. And roughly six-in-ten say the same about colleges and universities that benefited from slavery (63%) and descendants of families who engaged in the slave trade (60%).

Black Americans are skeptical change will happen

Bar chart showing little hope among Black adults that changes to address racial inequality are likely

Even though Black Americans’ visions for social change are clear, very few expect them to be implemented. Overall, 44% of Black adults say equality for Black people in the U.S. is a little or not at all likely. A little over a third (38%) say it is somewhat likely and only 13% say it is extremely or very likely.

They also do not think specific institutions will change. Two-thirds of Black adults say changes to the prison system (67%) and the courts and judicial process (65%) that would ensure fair treatment for Black people are a little or not at all likely in their lifetime. About six-in-ten (58%) say the same about policing. Only about one-in-ten say changes to policing (13%), the courts and judicial process (12%), and the prison system (11%) are extremely or very likely.

This pessimism is not only about the criminal justice system. The majority of Black adults say the political (63%), economic (62%) and health care (51%) systems are also unlikely to change in their lifetime.

Black Americans’ vision for social change includes reparations. However, much like their pessimism about institutional change, very few think they will see reparations in their lifetime. Among Black adults who say the descendants of people enslaved in the U.S. should be repaid, 82% say reparations for slavery are unlikely to occur in their lifetime. About one-in-ten (11%) say repayment is somewhat likely, while only 7% say repayment is extremely or very likely to happen in their lifetime.

Black Democrats, Republicans differ on assessments of inequality and visions for social change

Bar chart showing Black adults differ by party in their views on racial discrimination and changes to policing

Party affiliation is one key point of difference among Black Americans in their assessments of racial inequality and their visions for social change. Black Republicans and Republican leaners are more likely than Black Democrats and Democratic leaners to focus on the acts of individuals. For example, when summarizing the nature of racism against Black people in the U.S., the majority of Black Republicans (59%) say racist acts committed by individual people is a bigger problem for Black people than racism in our laws. Black Democrats (41%) are less likely to hold this view.

Black Republicans (45%) are also more likely than Black Democrats (21%) to say that Black people who cannot get ahead in the U.S. are mostly responsible for their own condition. And while similar shares of Black Republicans (79%) and Democrats (80%) say they experience racial discrimination on a regular basis, Republicans (64%) are more likely than Democrats (36%) to say that most Black people who want to get ahead can make it if they are willing to work hard.

On the other hand, Black Democrats are more likely than Black Republicans to focus on the impact that racial inequality has on Black Americans. Seven-in-ten Black Democrats (73%) say racial discrimination is the main reason many Black people cannot get ahead in the U.S, while about four-in-ten Black Republicans (44%) say the same. And Black Democrats are more likely than Black Republicans to say racism (67% vs. 46%) and police brutality (65% vs. 44%) are extremely big problems for Black people today.

Black Democrats are also more critical of U.S. institutions than Black Republicans are. For example, Black Democrats are more likely than Black Republicans to say the prison system (57% vs. 35%), policing (52% vs. 29%) and the courts and judicial process (50% vs. 35%) should be completely rebuilt for Black people to be treated fairly.

While the share of Black Democrats who want to see large-scale changes to the criminal justice system exceeds that of Black Republicans, they share similar views on police funding. Four-in-ten each of Black Democrats and Black Republicans say funding for police departments in their communities should remain the same, while around a third of each partisan coalition (36% and 37%, respectively) says funding should increase. Only about one-in-four Black Democrats (24%) and one-in-five Black Republicans (21%) say funding for police departments in their communities should decrease.

Among the survey’s other findings:

Black adults differ by age in their views on political strategies. Black adults ages 65 and older (77%) are most likely to say voting is an extremely or very effective strategy for moving Black people toward equality. They are significantly more likely than Black adults ages 18 to 29 (48%) and 30 to 49 (60%) to say this. Black adults 65 and older (48%) are also more likely than those ages 30 to 49 (38%) and 50 to 64 (42%) to say protesting is an extremely or very effective strategy. Roughly four-in-ten Black adults ages 18 to 29 say this (44%).

Gender plays a role in how Black adults view policing. Though majorities of Black women (65%) and men (56%) say police brutality is an extremely big problem for Black people living in the U.S. today, Black women are more likely than Black men to hold this view. When it comes to criminal justice, Black women (56%) and men (51%) are about equally likely to share the view that the prison system should be completely rebuilt to ensure fair treatment of Black people. However, Black women (52%) are slightly more likely than Black men (45%) to say this about policing. On the matter of police funding, Black women (39%) are slightly more likely than Black men (31%) to say police funding in their communities should be increased. On the other hand, Black men are more likely than Black women to prefer that funding stay the same (44% vs. 36%). Smaller shares of both Black men (23%) and women (22%) would like to see police funding decreased.

Income impacts Black adults’ views on reparations. Roughly eight-in-ten Black adults with lower (78%), middle (77%) and upper incomes (79%) say the descendants of people enslaved in the U.S. should receive reparations. Among those who support reparations, Black adults with upper and middle incomes (both 84%) are more likely than those with lower incomes (75%) to say educational scholarships would be an extremely or very helpful form of repayment. However, of those who support reparations, Black adults with lower (72%) and middle incomes (68%) are more likely than those with higher incomes (57%) to say cash payments would be an extremely or very helpful form of repayment for slavery.

Black adults in the September 2020 survey only include those who say their race is Black alone and are non-Hispanic. The same is true only for the questions of improvements to Black people’s lives and equality in the United States in the October 2021 survey. Throughout the rest of this report, Black adults include those who say their race is Black alone and non-Hispanic; those who say their race is Black and at least one other race and non-Hispanic; or Black and Hispanic, unless otherwise noted. ↩

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Home » Case Study – Methods, Examples and Guide

Case Study – Methods, Examples and Guide

Table of Contents

A case study is a research method that involves an in-depth examination and analysis of a particular phenomenon or case, such as an individual, organization, community, event, or situation.

It is a qualitative research approach that aims to provide a detailed and comprehensive understanding of the case being studied. Case studies typically involve multiple sources of data, including interviews, observations, documents, and artifacts, which are analyzed using various techniques, such as content analysis, thematic analysis, and grounded theory. The findings of a case study are often used to develop theories, inform policy or practice, or generate new research questions.

Types of Case Study

Types and Methods of Case Study are as follows:

Single-Case Study

A single-case study is an in-depth analysis of a single case. This type of case study is useful when the researcher wants to understand a specific phenomenon in detail.

For Example , A researcher might conduct a single-case study on a particular individual to understand their experiences with a particular health condition or a specific organization to explore their management practices. The researcher collects data from multiple sources, such as interviews, observations, and documents, and uses various techniques to analyze the data, such as content analysis or thematic analysis. The findings of a single-case study are often used to generate new research questions, develop theories, or inform policy or practice.

Multiple-Case Study

A multiple-case study involves the analysis of several cases that are similar in nature. This type of case study is useful when the researcher wants to identify similarities and differences between the cases.

For Example, a researcher might conduct a multiple-case study on several companies to explore the factors that contribute to their success or failure. The researcher collects data from each case, compares and contrasts the findings, and uses various techniques to analyze the data, such as comparative analysis or pattern-matching. The findings of a multiple-case study can be used to develop theories, inform policy or practice, or generate new research questions.

Exploratory Case Study

An exploratory case study is used to explore a new or understudied phenomenon. This type of case study is useful when the researcher wants to generate hypotheses or theories about the phenomenon.

For Example, a researcher might conduct an exploratory case study on a new technology to understand its potential impact on society. The researcher collects data from multiple sources, such as interviews, observations, and documents, and uses various techniques to analyze the data, such as grounded theory or content analysis. The findings of an exploratory case study can be used to generate new research questions, develop theories, or inform policy or practice.

Descriptive Case Study

A descriptive case study is used to describe a particular phenomenon in detail. This type of case study is useful when the researcher wants to provide a comprehensive account of the phenomenon.

For Example, a researcher might conduct a descriptive case study on a particular community to understand its social and economic characteristics. The researcher collects data from multiple sources, such as interviews, observations, and documents, and uses various techniques to analyze the data, such as content analysis or thematic analysis. The findings of a descriptive case study can be used to inform policy or practice or generate new research questions.

Instrumental Case Study

An instrumental case study is used to understand a particular phenomenon that is instrumental in achieving a particular goal. This type of case study is useful when the researcher wants to understand the role of the phenomenon in achieving the goal.

For Example, a researcher might conduct an instrumental case study on a particular policy to understand its impact on achieving a particular goal, such as reducing poverty. The researcher collects data from multiple sources, such as interviews, observations, and documents, and uses various techniques to analyze the data, such as content analysis or thematic analysis. The findings of an instrumental case study can be used to inform policy or practice or generate new research questions.

Case Study Data Collection Methods

Here are some common data collection methods for case studies:

Interviews involve asking questions to individuals who have knowledge or experience relevant to the case study. Interviews can be structured (where the same questions are asked to all participants) or unstructured (where the interviewer follows up on the responses with further questions). Interviews can be conducted in person, over the phone, or through video conferencing.

Observations

Observations involve watching and recording the behavior and activities of individuals or groups relevant to the case study. Observations can be participant (where the researcher actively participates in the activities) or non-participant (where the researcher observes from a distance). Observations can be recorded using notes, audio or video recordings, or photographs.

Documents can be used as a source of information for case studies. Documents can include reports, memos, emails, letters, and other written materials related to the case study. Documents can be collected from the case study participants or from public sources.

Surveys involve asking a set of questions to a sample of individuals relevant to the case study. Surveys can be administered in person, over the phone, through mail or email, or online. Surveys can be used to gather information on attitudes, opinions, or behaviors related to the case study.

Artifacts are physical objects relevant to the case study. Artifacts can include tools, equipment, products, or other objects that provide insights into the case study phenomenon.

How to conduct Case Study Research

Conducting a case study research involves several steps that need to be followed to ensure the quality and rigor of the study. Here are the steps to conduct case study research:

Define the research questions: The first step in conducting a case study research is to define the research questions. The research questions should be specific, measurable, and relevant to the case study phenomenon under investigation.
Select the case: The next step is to select the case or cases to be studied. The case should be relevant to the research questions and should provide rich and diverse data that can be used to answer the research questions.
Collect data: Data can be collected using various methods, such as interviews, observations, documents, surveys, and artifacts. The data collection method should be selected based on the research questions and the nature of the case study phenomenon.
Analyze the data: The data collected from the case study should be analyzed using various techniques, such as content analysis, thematic analysis, or grounded theory. The analysis should be guided by the research questions and should aim to provide insights and conclusions relevant to the research questions.
Draw conclusions: The conclusions drawn from the case study should be based on the data analysis and should be relevant to the research questions. The conclusions should be supported by evidence and should be clearly stated.
Validate the findings: The findings of the case study should be validated by reviewing the data and the analysis with participants or other experts in the field. This helps to ensure the validity and reliability of the findings.
Write the report: The final step is to write the report of the case study research. The report should provide a clear description of the case study phenomenon, the research questions, the data collection methods, the data analysis, the findings, and the conclusions. The report should be written in a clear and concise manner and should follow the guidelines for academic writing.

Examples of Case Study

Here are some examples of case study research:

The Hawthorne Studies : Conducted between 1924 and 1932, the Hawthorne Studies were a series of case studies conducted by Elton Mayo and his colleagues to examine the impact of work environment on employee productivity. The studies were conducted at the Hawthorne Works plant of the Western Electric Company in Chicago and included interviews, observations, and experiments.
The Stanford Prison Experiment: Conducted in 1971, the Stanford Prison Experiment was a case study conducted by Philip Zimbardo to examine the psychological effects of power and authority. The study involved simulating a prison environment and assigning participants to the role of guards or prisoners. The study was controversial due to the ethical issues it raised.
The Challenger Disaster: The Challenger Disaster was a case study conducted to examine the causes of the Space Shuttle Challenger explosion in 1986. The study included interviews, observations, and analysis of data to identify the technical, organizational, and cultural factors that contributed to the disaster.
The Enron Scandal: The Enron Scandal was a case study conducted to examine the causes of the Enron Corporation’s bankruptcy in 2001. The study included interviews, analysis of financial data, and review of documents to identify the accounting practices, corporate culture, and ethical issues that led to the company’s downfall.
The Fukushima Nuclear Disaster : The Fukushima Nuclear Disaster was a case study conducted to examine the causes of the nuclear accident that occurred at the Fukushima Daiichi Nuclear Power Plant in Japan in 2011. The study included interviews, analysis of data, and review of documents to identify the technical, organizational, and cultural factors that contributed to the disaster.

Application of Case Study

Case studies have a wide range of applications across various fields and industries. Here are some examples:

Business and Management

Case studies are widely used in business and management to examine real-life situations and develop problem-solving skills. Case studies can help students and professionals to develop a deep understanding of business concepts, theories, and best practices.

Case studies are used in healthcare to examine patient care, treatment options, and outcomes. Case studies can help healthcare professionals to develop critical thinking skills, diagnose complex medical conditions, and develop effective treatment plans.

Case studies are used in education to examine teaching and learning practices. Case studies can help educators to develop effective teaching strategies, evaluate student progress, and identify areas for improvement.

Social Sciences

Case studies are widely used in social sciences to examine human behavior, social phenomena, and cultural practices. Case studies can help researchers to develop theories, test hypotheses, and gain insights into complex social issues.

Law and Ethics

Case studies are used in law and ethics to examine legal and ethical dilemmas. Case studies can help lawyers, policymakers, and ethical professionals to develop critical thinking skills, analyze complex cases, and make informed decisions.

Purpose of Case Study

The purpose of a case study is to provide a detailed analysis of a specific phenomenon, issue, or problem in its real-life context. A case study is a qualitative research method that involves the in-depth exploration and analysis of a particular case, which can be an individual, group, organization, event, or community.

The primary purpose of a case study is to generate a comprehensive and nuanced understanding of the case, including its history, context, and dynamics. Case studies can help researchers to identify and examine the underlying factors, processes, and mechanisms that contribute to the case and its outcomes. This can help to develop a more accurate and detailed understanding of the case, which can inform future research, practice, or policy.

Case studies can also serve other purposes, including:

Illustrating a theory or concept: Case studies can be used to illustrate and explain theoretical concepts and frameworks, providing concrete examples of how they can be applied in real-life situations.
Developing hypotheses: Case studies can help to generate hypotheses about the causal relationships between different factors and outcomes, which can be tested through further research.
Providing insight into complex issues: Case studies can provide insights into complex and multifaceted issues, which may be difficult to understand through other research methods.
Informing practice or policy: Case studies can be used to inform practice or policy by identifying best practices, lessons learned, or areas for improvement.

Advantages of Case Study Research

There are several advantages of case study research, including:

In-depth exploration: Case study research allows for a detailed exploration and analysis of a specific phenomenon, issue, or problem in its real-life context. This can provide a comprehensive understanding of the case and its dynamics, which may not be possible through other research methods.
Rich data: Case study research can generate rich and detailed data, including qualitative data such as interviews, observations, and documents. This can provide a nuanced understanding of the case and its complexity.
Holistic perspective: Case study research allows for a holistic perspective of the case, taking into account the various factors, processes, and mechanisms that contribute to the case and its outcomes. This can help to develop a more accurate and comprehensive understanding of the case.
Theory development: Case study research can help to develop and refine theories and concepts by providing empirical evidence and concrete examples of how they can be applied in real-life situations.
Practical application: Case study research can inform practice or policy by identifying best practices, lessons learned, or areas for improvement.
Contextualization: Case study research takes into account the specific context in which the case is situated, which can help to understand how the case is influenced by the social, cultural, and historical factors of its environment.

Limitations of Case Study Research

There are several limitations of case study research, including:

Limited generalizability : Case studies are typically focused on a single case or a small number of cases, which limits the generalizability of the findings. The unique characteristics of the case may not be applicable to other contexts or populations, which may limit the external validity of the research.
Biased sampling: Case studies may rely on purposive or convenience sampling, which can introduce bias into the sample selection process. This may limit the representativeness of the sample and the generalizability of the findings.
Subjectivity: Case studies rely on the interpretation of the researcher, which can introduce subjectivity into the analysis. The researcher’s own biases, assumptions, and perspectives may influence the findings, which may limit the objectivity of the research.
Limited control: Case studies are typically conducted in naturalistic settings, which limits the control that the researcher has over the environment and the variables being studied. This may limit the ability to establish causal relationships between variables.
Time-consuming: Case studies can be time-consuming to conduct, as they typically involve a detailed exploration and analysis of a specific case. This may limit the feasibility of conducting multiple case studies or conducting case studies in a timely manner.
Resource-intensive: Case studies may require significant resources, including time, funding, and expertise. This may limit the ability of researchers to conduct case studies in resource-constrained settings.

About the author

Muhammad Hassan

Researcher, Academic Writer, Web developer

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Having MS may marginally increase likelihood of cervical cancer: Study

But 'robust' genetic analysis finds no link to 14 other cancer types

by Margarida Maia, PhD | April 25, 2024

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Three people use circles and a bar to form an oversized percentage sign against the backdrop of an zigzag arrow portraying increase.

There’s no evidence to suggest that multiple sclerosis (MS) directly causes most cancers, but having the condition may marginally increase the likelihood of developing cervical cancer, according to a new study from China.

That study found “no causal relationship between MS and 15 types of cancers except cervical cancer,” the researchers wrote.

However, the team stressed that their “robust” analysis “showed that MS was only associated with a marginal increased risk of cervical cancer.”

The study, “ Association between multiple sclerosis and cancer risk: A two-sample Mendelian randomization study ,” was published in PLOS One .

An illustration of neurons covered by the myelin sheath.

Cancer Researchers’ Discovery May Benefit MS Studies

Using a mendelian analysis to investigate ms and cancer link.

MS occurs when the immune system wrongly attacks the protective covering of nerve fibers in the brain and spinal cord, leading to a range of symptoms . It remains unclear why this happens, but it may be caused by a combination of environmental and genetic factors .

Research on MS and cancer has shown mixed results. While some studies suggest MS may protect against cancer, others show it may increase the risk for such diseases .

Now, a team from the Sun Yat-sen University Cancer Center, in Guangzhou, turned to Mendelian randomization to better assess the causal effect of MS in cancer — without potential confounding factors that could influence the results. A confounding factor is an unmeasured variable that influences both the supposed cause and effect in a study.

Mendelian randomization is a type of analysis that uses genetic variations as proxies for an exposure of interest — in this case, genetic variations linked with a greater susceptibility to multiple sclerosis as proxies of MS — to investigate the association between the exposure and an outcome.

If there is a causal relationship between the two, then that association should also be observed between the genetic variants tied to greater MS susceptibility and cancer.

Genetic data related to MS came from more than 115,000 samples from the International Multiple Sclerosis Genetics Consortium , while cancer data came from the U.K. Biobank, a database of genetic and health information from more than 500,000 volunteers.

Overall, the researchers identified 107 single nucleotide polymorphisms (SNPs), or variations at a single position in the DNA, that were strongly linked to MS. However, five were linked to smoking and the Epstein–Barr virus , which are risk factors for both MS and cancer, and were thus excluded from the analysis.

A scientist works with a petri dish in a lab, alongside a rack of four vials filled with liquid.

Astrocytes, much like immune cells, can drive inflammation in MS

More research needed on biological mechanisms underlying this link.

The researchers then sought to determine if the 102 SNPs that remained were associated with any of the 15 cancers registered in the U.K. Biobank. These included cancers of the prostate, breast, bladder, brain, cervix, throat, liver, and lung. Other types, such as ovarian, colorectal, and melanoma (a skin cancer) also were included.

The results showed no causal link between MS and most cancers — 14 specifically.

There was, however, a “marginal” increase in the likelihood of cervical cancer — by 0.04% — in people with MS variants compared with individuals who lacked these genetic variations, the researchers found.

The intricate biological mechanisms underpinning this relationship remain elusive and warrant further exploration.

The scientists wrote that they “suspect that the occurrence of premalignant conditions and cervical cancer might be associated with the drugs used in MS treatment.” But, the team noted that more research is needed to better understand this link.

“The intricate biological mechanisms underpinning this relationship remain elusive and warrant further exploration,” they wrote.

Overall, the team concluded, “This study reveals that MS is only causally associated with a marginal increased risk of cervical cancer and shows no association with other types of cancer.”

About the Author

Obesity medications linked to reduced chance of MS in real world

Depression in pregnancy linked to autoimmune disease, especially MS

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Relapses found to drive disability worsening in 1st years of MS

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Types of Research – Explained with Examples

Types of Research

Classification of Types of Research

According to its Purpose

Applied Research

According to your Depth of Scope

Descriptive Research

Explanatory Research

Correlational Research

According to the Type of Data Used

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Non-Experimental Research

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According to the Type of Inference

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Hypothetical-Deductive Investigation

According to the Time in Which it is Carried Out

Cross-Sectional Study (also referred to as Synchronous Research)

According to The Sources of Information

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According to How the Data is Obtained

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An introduction to different types of study design

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8 Different Types Of Research [With Examples] | In 2024

8. According to the Depth of Scope

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7. According To The Type Of Inference

7.2 Inductive Research

7.3 Hypothetico-deductive Research

6. Based On Information Source

6.2 Secondary Research

5 According to the Data Type Used In Research

5.2 Quantitative Research

4 How Data Is Collected

4.2 Laboratory research

4.3 Documentary Research

3. According to the Extent of Variable Manipulation

3.2 Non-Experimental Research

2. Time-Dependent Studies

2.2 Longitudinal Research

1. According To Its Purpose