Which of the following is a disadvantage of Repeated Measures Design?

Which of the following is a disadvantage of Repeated Measures Design?

• A. Demand characteristics are reduced.
• B. Order effects can occur.
• C. Can't be used for all tests.
• D. Requires fewer participants.

Answer: (B)

In a repeated measures design the same participants take part in all conditions. That setup helps control for individual differences and usually requires fewer participants, which is a clear advantage. The main downside, though, is order effects. The sequence in which tasks or conditions are presented can change how people respond—practice can improve performance, fatigue or boredom can reduce it, and experiencing one condition can influence performance on the next (carryover). These effects can mimic or obscure the true effect of the manipulation, threatening internal validity. Researchers try to counter this with counterbalancing or washout periods, but residual order effects can still complicate interpretation. The other options describe outcomes that aren’t the central disadvantage—fewer participants is actually a plus, and demand characteristics aren’t inherently reduced, nor is the design unsuitable for all tests.

In a repeated measures design the same participants take part in all conditions. That setup helps control for individual differences and usually requires fewer participants, which is a clear advantage. The main downside, though, is order effects. The sequence in which tasks or conditions are presented can change how people respond—practice can improve performance, fatigue or boredom can reduce it, and experiencing one condition can influence performance on the next (carryover). These effects can mimic or obscure the true effect of the manipulation, threatening internal validity. Researchers try to counter this with counterbalancing or washout periods, but residual order effects can still complicate interpretation. The other options describe outcomes that aren’t the central disadvantage—fewer participants is actually a plus, and demand characteristics aren’t inherently reduced, nor is the design unsuitable for all tests.