Faking self-reports of health behavior: a comparison between a within- and a between-subjects design

BACKGROUND: This study examines people's ability to fake their reported health behavior and explores the magnitude of such response distortion concerning faking of preventive health behavior and health risk behavior. As health behavior is a sensitive topic, people usually prefer privacy about it or they wish to create a better image of themselves (Fekken et al., 2012; Levy et al., 2018). Nevertheless, health behavior is often assessed by self-report questionnaires that are prone to faking. Therefore, it is important to examine the possible impact of such faking. METHODS: To replicate the findings and test their robustness, two study designs were realized. In the within-subjects-design, 142 participants repeatedly answered a health behavior questionnaire with an instruction to answer honestly, fake good, and fake bad. In the between-subjects design, 128 participants were randomly assigned to one of three groups that filled out the health behavior questionnaire with only one of the three instructions. RESULTS: Both studies showed that successful faking of self-reported preventive and health risk behavior was possible. The magnitude of such faking effects was very large in the within-subjects design and somewhat smaller in the between-subjects design. CONCLUSION: Even though each design has its inherent merits and problems, caution is indicated regarding faking effects.