The effectiveness of the item count technique in eliciting valid answers to sensitive questions : an evaluation in the context of self-reported delinquency

"Surveys often contain sensitive questions, that is, questions about private, illegal, or socially undesirable behavior. When asked directly in standard survey modes, respondents tend to underreport these behaviors, yielding biased results. One method that promises more valid estimates than direct questioning (DQ) is the item count technique (ICT). In this paper, methodological benefits and disadvantages of the ICT, as compared to DQ, are empirically evaluated with regard to questions on self-reported delinquency. We present findings from a face-to-face survey of 552 respondents who had been convicted under criminal law prior to the survey. The results show that, first, subjective measures of survey quality such as trust in anonymity or willingness to respond are not affected positively by the ICT with the exception that interviewers feel less uncomfortable asking sensitive questions in ICT mode than in DQ mode. Second, all prevalence estimates of self-reported delinquent behaviors are significantly higher in ICT than in DQ mode. Third, a regression model on determinants of response behavior indicates that the effect of the ICT on response validity varies by gender. All in all, our results are in favor of the ICT. This technique is a promising alternative to other special questioning techniques such as the much more complicated randomized response technique (RRT)." (author's abstract