Obtaining reports of sensitive behavior: a comparison of substance use reports from telephone and face-to-face interviews

Few studies comparing telephone and in-person surveys have examined response differentials to sensitive questions. This paper examines responses to a series of substance use questions asked of samples of university students interviewed face to face and via telephone. Consistent differences are found to exist, with in-person respondents being more likely to report having used a number of substances, including tobacco and several illegal drugs. Analysis suggests that these differences are attributable to a method rather than a selection effect.