Observational Study: Definitions And Variations

There are many different types of studies out there, each one serving its own unique purpose. Sometimes, it’s difficult to research specific events or phenomena without manipulating an element of the study to produce the results.

An observational study is a type of study that is used for many different purposes today. If you’re curious to learn more about it, keep reading. Here, we’ll cover everything from the observational study definition to how it works, different types, the ethics behind it, and more.

Observational Study Definition

According to a dictionary of medical-related terms by Cancer.gov, the definition of observational study is as follows:

“A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).”

In other words, unlike other studies where doctors or scientists attempt to conduct research on things like the effect of new drugs or treatments on a person or illness, in an observational study, no outside factors are added into the mix. In that way, observational studies are not like experiments where external elements usually play a big role.

In an observational study, researchers will attempt to look at a treatment, risk factor, test, or some other type of intervention without changing who is exposed to it. Researchers will make no attempts to manipulate the study in any way, and, as the name implies, their goal with this kind of study is just to observe.

Types of Observational Studies

There are a few different types of observational studies: cohort studies, case-control studies, and experimental studies. Let’s take a closer look at each one.

Cohort studies

In a cohort study, researchers look at people who are linked in a specific way. For example, a birth cohort is a group of people that are born around the same time. Researchers will observe a group to see what happens when each individual is exposed to a certain variable compared to others who aren’t exposed.

Case-control studies

In a case-control study, researchers look for participants with existing health problems, or cases, and then contrast them with other people who don’t have that same problem. They then compare the two groups in relation to different exposures.

Experimental studies

In experimental studies, researchers will introduce some form of intervention and then observe the effects. For example, in a randomized control trial, people are randomly divided into two groups where one group will receive an intervention, like a new drug, and the second will receive nothing or a placebo. Then, researchers will look at what happens to people in both groups and note any differences.

The Strengths and Weaknesses of Observational Studies

Like anything else, observational studies have both strengths and weaknesses. At times, these types of studies are the best way for researchers to look at a certain topic, especially when ethics are involved.

For example, you wouldn’t necessarily expose participants to something harmful or potentially fatal for the purpose of research.

One of the strengths of observational studies is that it is the most efficient way to research certain things, like rare conditions, when applying case-control studies. At other times, cohort studies can be really effective if you’re able to conduct the research over a longer period of time.

That being said, observational studies aren’t without their weaknesses, more specifically, they’re open to bias. As an example, in a cohort study, you might look at the link between elevated blood pressure and people who exercise frequently. However, the bias might be that the people who exercise frequently are already leading a healthier lifestyle and might have better diets than the second group.

Observational Studies and Ethics

As we briefly touched upon earlier, it wouldn’t be ethical to run any type of trial on unsuspecting participants. There are some things that would be considered medically unethical to do in an observational study.

As an example, it would be difficult to conduct a trial of the long-term effects of smoking on the lungs and overall health. In such a study, participants would have to be randomized and put into two groups: those who smoke and those who don’t. These groups would then be observed over time. However, since the long-term effects include things like lung cancer or death, the ethics here are questionable.

This experiment would work if researchers simply surveyed and observed the smoking status of people who are already smokers, but then the test wouldn’t be randomized and other factors and biases can be at play.

Examples of Observational Studies

In order to have a better understanding of observational studies, let’s take a look at some examples.

A simple example of an observational study is someone surveying people on a busy street about any topic, such as their favorite food. Then, this person would take that information and see if there are enough restaurants serving the most commonly answered foods in that area. In this situation, the researcher is simply observing the answers but not influencing the results.

In a second example of an observational study, a researcher might be studying the effects of eating sugary food on a person’s health. In a test group of 400 people, 200 of them will eat sugary foods over a year while another 200 won’t, and then each group will be observed. At the end of the test, each group will be assessed for overall health, and the data will be analyzed in order to come to some conclusion. Again, the researcher here hasn’t manipulated the study itself, just observed the participants.

To Wrap Up

Hopefully, after reading the observational study definition, examples, and other details, you have a better idea of how it’s used in science and research.

If you’re interested in conducting observational studies and research in your career, then you should start out with a degree in health science. At University of the People, we offer an entirely tuition-free and online health science degree so that you can study the basics before learning more about specific research methods.