Which of the following is a disadvantage of the matched pairs design?

Which of the following is a disadvantage of the matched pairs design?

• A. Time consuming
• B. Lots of participants are required
• C. Hard to match participants on all variables
• D. Not very economical

Answer: (C)

Matching participants aims to create equivalent groups by pairing individuals on key characteristics, then assigning within each pair. The main drawback is that it’s extremely hard to match people on every variable that could influence the outcome. Even when you pair on obvious factors like age or baseline performance, there are countless other traits—some unmeasured—that can differ between pairs. Those hidden differences can still influence results and blur the effect you’re studying. This makes the design vulnerable to confounds because you can’t guarantee perfect equivalence between groups. You might compensate by spending a lot of time finding close matches, which is why this approach is often described as time-consuming and less economical. However, the core issue that makes matched pairs a disadvantage is the difficulty of matching on all relevant variables, not just the practical effort involved.

Matching participants aims to create equivalent groups by pairing individuals on key characteristics, then assigning within each pair. The main drawback is that it’s extremely hard to match people on every variable that could influence the outcome. Even when you pair on obvious factors like age or baseline performance, there are countless other traits—some unmeasured—that can differ between pairs. Those hidden differences can still influence results and blur the effect you’re studying. This makes the design vulnerable to confounds because you can’t guarantee perfect equivalence between groups.

You might compensate by spending a lot of time finding close matches, which is why this approach is often described as time-consuming and less economical. However, the core issue that makes matched pairs a disadvantage is the difficulty of matching on all relevant variables, not just the practical effort involved.