Abstract
When a researcher decides to collect data by means of survey interviews, he or she makes the assumption that all the respondents have sufficient cognitive and communicative skills to execute the respondent's role adequately. In this article we validate the explanation that older and less educated respondents are difficult to interview because they do not have sufficient communicative skills. To determine the respondent's cognitive and communicative skills we use behavioral coding of the respondent–interviewer interaction. The analysis makes clear that most respondents have enough skills to accomplish their role as respondents. However, there is a small group of respondents who have insufficient skills. As expected, these difficult-to-interview respondents are older and less educated.