What is counterbalancing and why is it used?

• A. It randomizes participants into groups.
• B. It alternates the order of conditions to control for order effects.
• C. It increases the sample size to improve power.
• D. It eliminates the need for a control group.

Answer: (B)

Counterbalancing is a strategy used when the same participants experience multiple conditions. Its purpose is to prevent the order in which those conditions are presented from influencing the results. If you always put one condition first, any improvement, fatigue, or carryover from doing the first task could inflate or deflate responses in the second task. By varying the order across participants (for example, some do the conditions in one order, others in the opposite order, or using more balanced schedules), these order effects are distributed evenly. This way, any systematic influence of order cancels out on average, making it clearer whether the observed differences come from the conditions themselves rather than the sequence in which they were experienced. It’s not about randomizing participants into groups, increasing sample size, or removing the need for a control group.