Background: Even though the validity of self-reports of sensitive behaviors is threatened by social desirability bias, interviews and questionnaires are widely used in epidemiologic surveys on these topics.
Methods: In the randomized-response technique, a randomization device is used to determine whether participants are asked to respond truthfully or whether they are prompted to provide a prespecified response. In this study, the randomized-response technique was extended by using a cheating-detection modification to obtain more valid data. The survey was on the dental hygiene habits of Chinese college students.
Results: Whereas only 35% of men and 10% of women admitted to insufficient dental hygiene when questioned directly, 51% of men and 20% of women attested to this socially undesirable behavior in a randomized-response survey.
Conclusions: Given the considerable discrepancy between the results obtained by direct questioning and by using the randomized-response technique, we propose that this technique be considered for use in epidemiologic studies of sensitive behaviors.