Within-Subjects Design

Examples of Within-Subjects Design

Hypothetically, basic combat training in the military provides an example of a within-subjects design. The first characteristic of this event is the [Page 1878]formation of groups of about 40 to 50 individuals. The second characteristic of training is the interaction the participants have with training instructors who work with the participants on physical training, mental conditioning, military knowledge, and decorum. The goal of basic training involves taking a person at one stage of life and experience and creating a person who acts and thinks like a soldier. The analysis would probably involve a pretest as well as a posttest, with a definable goal: for the participant to meet or surpass the minimal scores required by the military for the performance of duties.

The pretest could provide an initial fitness assessment. During this time each individual participant (or a “recruit” in this military scenario) must do as many push-ups and sit-ups as possible in an allotted time and run a given distance while being timed. The expectation is that the person, after completing weeks of training, will be able to meet minimal performance requirements for those tests. For this example, assume that the group as a whole did poorly on the push-up portion of the initial assessment. The training instructors would receive this data and then decide what program of training offers the most effective means for improving the performance of the recruits.

Over the course of the next few weeks, the group engages in designated push-up and strength-training exercises. The belief of the instructors is that the group as a whole will demonstrate improved performance on the push-up test at the next assessment. Should this training be successful, the instructors should see improved scores at the next assessment. At the conclusion of basic training, the posttest occurs. The posttest constitutes the final physical fitness assessment. Should the training operate as intended, the repeated measurement should show the group as a whole meeting or surpassing the minimal physical fitness goals with incremental improvements made from each prior fitness assessment.

...