Which strategy helps reduce recall bias when collecting exposure information?

• A. Increase Sample Size
• B. Use Retrospective Self-Report Only
• C. Validate Subject-Reported Exposure Information With Objective Tests
• D. Randomize Participants To Control Groups

Answer: (C)

Reducing recall bias means making exposure data as accurate as possible by checking what participants say against objective information. People often forget past exposures or report them inaccurately, especially in retrospective studies, and this systematic misreporting can distort the link between exposure and outcome. By validating what participants report with objective measures—like lab tests, medical records, or exposure registries—you can confirm or correct self-reported data. This verification reduces misclassification of exposure and leads to more trustworthy study results.

Increasing sample size helps reduce random error but doesn’t fix systematic errors in data collection. Relying on retrospective self-report alone amplifies recall bias rather than mitigates it. Randomizing participants to control groups addresses confounding and balance between groups, but it doesn’t directly correct inaccuracies in how exposure information is collected unless exposure data are validated.