Observation Study vs Experimental Study (with examples and full explanation/comparison)

4 min readMay 2, 2023

Observational studies and experimental studies are two types of research designs used in scientific research. Easy understanding, we can say Observational is where you observe certain variables and try to determine if there is any correlation. Experimental is where you control certain variables and try to determine if there is any causality. Simply, an observational study is where nothing changes and just record what you see, but an experimental study is where you have a control group and a testable group.

Observational studies are research studies that observe and analyze the behavior or characteristics of a group of people or objects without influencing or manipulating them in any way. Researchers collect data by observing and measuring variables, such as behaviors, demographics, or medical conditions, and then analyze the data to identify patterns or relationships between the variables. The data collected in an observational study is typically descriptive, and it can be used to make predictions or develop theories about the behavior or characteristics of the population being studied. However, observational studies cannot prove causation, and the results may be influenced by confounding variables or biases. Also, Observational studies have limitations in generalizing results to the larger population because they often rely on a non-random or non-representative sample. In observational studies, researchers observe and measure pre-existing variables without intervention, and the sample is often based on convenience, accessibility, or availability of data.

Experimental studies, on the other hand, involve the manipulation of one or more variables to determine their effect on a particular outcome. Researchers randomly assign participants to either an experimental group, which receives the treatment or intervention being tested, or a control group, which does not receive the treatment. The researchers then measure the outcome of interest in both groups and compare the results to determine if the treatment had a significant effect. Experimental studies can establish causality because the researcher has control over the variables being manipulated, and any observed changes in the outcome can be attributed to the treatment. However, experimental studies may not always be feasible or ethical, and the results may not be generalizable to the larger population.

In summary, observational studies are used to observe and analyze behavior or characteristics without manipulating them, while experimental studies involve the manipulation of variables to determine causality. Both types of studies have their strengths and limitations, and the choice of study design depends on the research question and the feasibility and ethical considerations of the study.


Lets take a look into the examples from both studies:

Observational Study Examples:

  • A study that observes and records the behavior of children at a playground to determine if there is a relationship between physical activity and social behavior.
  • A study that examines medical records to determine if there is a correlation between a specific genetic mutation and the incidence of a certain disease.
  • A study that surveys employees to identify factors that contribute to job satisfaction.

Experimental Study Examples:

  • A study that investigates the effect of a new drug on the symptoms of a particular medical condition. Participants are randomly assigned to receive either the new drug or a placebo, and the outcomes are compared.
  • A study that tests the impact of a new teaching method on student performance. Students are randomly assigned to either the experimental group, which receives the new teaching method, or the control group, which receives the traditional teaching method.
  • A study that evaluates the effectiveness of a new marketing strategy. Customers are randomly assigned to either receive the new marketing message or the old one, and their responses are measured.

How to identify which is which?

One of the easy way to identify a study is an observational study and experimental study is the wording “randomly assigned” or “randomly picked/chosen”. It is often a good indicator that a study is experimental rather than observational. In an experimental study, participants are randomly assigned to different groups, which allows researchers to control for potential confounding variables and establish a cause-and-effect relationship between the intervention or treatment and the outcome. Worth to mention that ,One of the most common use of experimental study we often heard is A/B test which is a popular and practical application, and I will discuss A/B test in a separated story.

Observational studies, on the other hand, do not involve random assignment of participants to different groups. Instead, researchers observe and collect data on existing groups or populations and look for associations or correlations between variables.

Of course, the distinction between experimental and observational studies is not always clear-cut, and there may be studies that use elements of both designs. However, the presence of random assignment is generally a strong indication that a study is experimental and therefore more likely to establish causality.

To summarize it, lets look into the table of comparison between observation study and experimental study:

By SharkYun

Reference: (both link have quiz you can try to test your knowledge on identify the case is observational study or experimental study~)


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