The Difference between Within-Subject and Between-Subjects Experiments

The Difference between Within-Subject and Between-Subjects Experiments

In any research, be it quantitative, qualitative, or mixed study, its primary purpose is to inform action, collect evidence for given theories, and contribute to innovative knowledge in the field of study. Narrowing down, the quantitative research method naturally uses experimental procedures in conducting its scientific approach while utilizing two or more variables. The initial variable is a constant that can be manipulated to see the variation caused by the second variable (Voxco, 2021). In simpler terms, a scientific technique that is carried out in order to create a discovery, test a hypothesis, or show a known fact is referred to as an experiment (Jackson, 2015). Natural experiments, field, and laboratory are the three categories of experiments (Hole, 2006). Various design types may be used in these types of trials. Therefore, it is prudent to explore the two experimental methods – within-subject design and between-subject design.

According to Charness, Gneezy, & Kuhn (2012), a within-subject designed experiment involves each individual being exposed to more than a single treatment being tested, be it playing a game with two varying parameter values, answering various questions, or conducting tasks under many external stimuli while Budiu, (2018) suggest that between-subject research design involves various individuals testing each condition, in that each individual is exposed to only a single user interface. To illustrate, imagine that this experiment is looking at the consequences of taking a weekly quiz. The study's methodology would be to educate during the first four weeks of the semester rather than administering a weekly assessment. The same class would subsequently be subjected to weekly quizzes for the final four weeks of class. The instructor will compare the total results of the class on the pre-and post-tests after each set of four weeks to see if there is a substantial distinction. The teacher uses the same group for both the quiz and the absence of the quiz. Two or more sets of participants are used in a between-subject design.

A different component or variable is evaluated in each group. For example, the instructor evaluates the impact of daily quizzes using the same scenario as the within-subjects. The teacher would employ two distinct courses at the same curriculum level for this design. The weekly quizzes would be given to one class and not the other. Pre- and post-tests would be given to both classes to see if there is a substantial change in test results, indicating that weekly tests are helpful in learning.

Which Is Better: Between-Subjects or Within-Subjects?

This question, unfortunately, does not have a clear solution. As previously said, your independent variables might occasionally define the experimental design. However, in many cases, both models may be feasible.

Learning and transfer across circumstances are minimized when between-subjects are used. A person is more educated about a topic after completing a set of activities on a car-rental site than previously (Keren, 2014). For example, they may now know that automobile rental companies impose a surcharge for drivers under 21 or that a collision-damage waiver exists. That expertise will very certainly aid her in becoming more practical on a second car-rental site, even if the second site is much different from the first. In addition, participants are never exposed to multiple levels of the same independent variable when using a between-subject design, so knowledge transfer is not an issue.

Within-subject designs are less expensive to perform and involve fewer participants. However, you will frequently need a large number of data points (generally over 30) in each case to discover a significant variation between them. Each participant will contribute a data point for each entity level if you have a within-subject design. For example, 30 people will submit data for both sites in our car-rental project. However, if the research is between-subjects, you'll need twice as many participants to acquire the same sample size. As a result, the price is doubled (Keren, 2014).

References

Budiu R. (2018, May 13). Between-subjects vs. within-subjects study design. Nielsen Norman Group. https://www.nngroup.com/articles/between-within-subjects/

Charness, G., Gneezy, U., & Kuhn, M. A. (2012). Experimental methods: Between-subject and within-subject design. Journal of economic behavior & organization, 81(1), 1-8.

Hole, G. (2006). between-groups design. In G. Davey, Encyclopaedic dictionary of psychology. London, UK: Routledge. Retrieved from https://search-credoreferencecom.ezproxy2.apus.edu/content/entry/hodderdpsyc/between_groups_design/0

Jackson, S. L. (2015). Research methods and statistics: A critical thinking approach. Cengage Learning.

Keren, G. (2014). Between-or within-subjects design: A methodological dilemma. A handbook for data analysis in the behavioral sciences, 1, 257-272.

Voxco. (2021, February 26). Experimental research. https://www.voxco.com/blog/experimental-research/