Which of the following is an advantage of Repeated Measures Design?

• A. Randomization is not needed.
• B. No individual differences.
• C. More time consuming.
• D. Fewer participants are required.

Answer: (D)

Repeated measures design uses the same participants across all conditions, so individual differences between participants don’t add as much uncontrolled noise to the data. That means the manipulation’s effect is easier to detect because the error variance is reduced. With this greater sensitivity, you can achieve reliable results with fewer participants, which is why the advantage is described as needing fewer participants.

Note that order effects can still occur, so researchers usually counterbalance the order of conditions to control for that, rather than assuming randomness alone fixes the issue. Also, while individual differences between people still exist, they are held constant across conditions, not eliminated, and the claim that there are no individual differences isn’t accurate. The idea that it is more time consuming isn’t an inherent advantage; in fact, this design can be more efficient in participant numbers even if it requires more management of order effects.