In this presentation we focus on the role of the interviewer in causing mode effects, contrasting modes in which an interviewer is used (face-to-face and telephone) with a mode without an interviewer (web). Other differences between modes, such as aural versus visual transmission of information, are held constant where possible.

The presence of an interviewer is hypothesised to motivate respondents to generate an accurate answer and to reduce the difficulty of the task by offering support and providing explanations of what is needed. However, an interviewer will reduce the privacy of the reporting situation, which may have an impact on respondents’ willingness to answer truthfully. Here we would also expect differences between face-to-face, where the interviewer is with the respondent, and telephone, where the interviewer is physically separated.

Based on a UK ESRC-funded mixed modes experiment, this presentation compares the prevalence of indicators of satisficing and socially desirable responding between interviewer and self-completion modes. The study disentangles the effects of question design, difficulty and sensitivity in relation to the responses obtained. Results show differences between interviewer and self-completion modes: i. in levels of satisficing; and ii. in socially desirable responding to sensitive questions (although social desirability did not differ between the interviewer modes). Patterns indicative of the effect of interviewer presence or absence can be observed across different types of survey question. Comparative results from a cognitive interviewing follow-up that cast light on the quantitative experiment results will also be presented.