Observational Study Vs. Experimental Study: What’s The Difference?

While the majority of us are familiar with the idea of an experiment or an observation in the vernacular, you may wonder if it’s any different in scientific jargon. The short answer is no; however, there is more specificity to it in terms of scientific studies.

Merriam-Webster has several different definitions for the word observation, but the one that’s the closest to the scientific sense is “an act of recognizing and noting a fact or occurrence often involving measurement with instruments.”

Experiment, on the other hand, is defined as “an operation or procedure carried out under controlled conditions in order to discover an unknown effect or law, to test or establish a hypothesis, or to illustrate a known law.”

So, in short, an observational study involves simply watching and recording what happens. An experiential study, on the other hand, involves carrying out a procedure and controlling the conditions under which it happens.

Key Takeaways:

What Is an Observational Study?

Observational studies are useful in many different circumstances. They’re used in all manners of fields, from biology, ecology, sociology, and psychology.

One of the most prevalent forms of an observational study would be a survey. When issuing a survey, those running them do their level best to remove themselves from the answers given. Surveys are most often used in sociology and psychology, though they have many uses in medicine as well.

An observational study could also involve watching wildlife. This is a common way that researchers learn more about the natural world, as they observe how the ecosystem interacts without interfering with it.

Observational studies also have the bonus of being much less expensive to put together and run than experimental studies. It requires less time, staff, and planning to execute.

There are several different types of observational studies that are used under different conditions.

• Cohort studies. Cohort studies are, by design, longitudinal, meaning that they’re long-term. They’re created by selecting a “cohort,” which is a group that shares a common characteristic. This can be a group that’s born at the same time, has the same health condition, or engages in a particular behavior, such as smoking.

• Case-control studies. Case-control studies involve having both a “case” group and a “control” group. Most people are familiar with the idea of a control group – a selection of people that don’t do whatever’s in the experiment.

  For example, if you’re comparing the effect pets have on mental health, the people in your control group wouldn’t have a pet. Alternatively, the case group would have a pet.

• Cross-sectional studies. These types of studies narrow your observations to a period in time. This time period can be a month, say if you’re looking at how many people were killed in car crashes. Or it could be a physical observation, such as counting the number of car crash victims that come into the hospital emergency room on a particular night.

There are also different types of observation that are used in observational studies. These determine how the observer interacts – or doesn’t – with what’s being observed.

• Naturalistic observation. This involves observing participants react in a “real-life” situation. Researchers don’t influence the subjects’ behavior in hopes it will be as natural as possible.

• Covert observation. As the name implies, this type of observation requires that the participants don’t know that they’re being observed. Often done in public places in order to avoid ethical concerns.

• Systematic observation. This type of observation is based on counting how many times a particular behavior or phenomenon happens. The behavior isn’t influenced, and researchers need to follow a strict observation schedule.

• Quantitative observation. This type of observation relies on numerical data, such as the height or age of the subjects.

• Case study. A study of this type requires long-term observation of an individual or small group. The idea is that such an observation can then be generalized to a larger group.

• Participant observation. This is similar to the naturalistic observation in that it also observes real-life situations. However, the difference is that the researcher also participates in the activity – hence the name. Such as studying the culture of hospital staff while working as a nurse.

• Qualitative observation. An observational type that is focused on the five senses.

• Archival research. As the name suggests, this type of research is more removed. It involves investigating records rather than dealing with subjects or participants directly.

What Is an Experimental Study?

An experimental study involves altering conditions and measuring the results of that alteration. This can vary widely, with the best-known example being drug trials. The experimenter gives one group of people the new pharmaceutical while another group is given a placebo. The efficacy of the drug is then weighted against the severity of the side effects it produces.

Experimental studies are often the preferred method due to the fact that the conditions are more carefully controlled. This allows for greater scientific validity in the sense that they’re able to compensate and control for outside influences and factors, unlike observational studies.

Due to the fact that they’re so heavily controlled, they are, however, much more expensive. There are also circumstances where doing an experimental study would be unethical, such as studying the effects of corporal punishment on children.

No reasonable researcher could assign a cohort of children to be hit regularly while another group isn’t. Thus, that was studied via an observational study instead.

There are a few different varieties of experimental studies.

• Randomized controlled trials. The linchpin of this style of study is randomization. In this type, the control group and experimental group are randomly assigned to their positions. This is considered the most scientifically rigorous way to do the assignments because it prevents biases from having an effect.

• Community intervention trials. Rather than assigning individuals to be in the control group, a community intervention trial will select two different groups or communities.

  One community will receive the intervention (whatever they’re testing, be it a drug, different type of construction, or footpaths), and the other won’t. That’s how you get your control group and study group.

• Pragmatic clinical trials. This type of trial focuses on efficacy. It’s most often used in clinical trials, such as for a new medicine or treatment.

Author

Di Doherty

Di has been a writer for more than half her life. Most of her writing so far has been fiction, and she’s gotten short stories published in online magazines Kzine and Silver Blade, as well as a flash fiction piece in the Bookends review. Di graduated from Mary Baldwin College (now University) with a degree in Psychology and Sociology.