Which design element is specifically used to control for order effects in repeated-measures designs?

• A. Randomization
• B. Post-hoc analysis
• C. Counterbalancing
• D. Standardization

Answer: (C)

Order effects occur when the sequence in which participants experience conditions influences their responses. Counterbalancing addresses this by rotating the order of conditions across participants so each condition appears in every position an equal number of times. This spreads any sequence-related influence evenly, so comparisons between conditions reflect the conditions themselves rather than the order in which they were presented. For example, if there are two tasks, some participants do them in one order and others in the opposite order, balancing out practice, fatigue, or carryover effects across conditions. Randomization can reduce bias but doesn’t guarantee that all orders are represented equally, standardization keeps procedures the same but doesn’t fix the order issue, and post-hoc analysis deals with interpreting data after collection rather than preventing order effects during design.