Design effect and interviewer effects: Evidence from the Spanish ESS3-2006 Data

In 2007 the first Quality Enhancement Meeting on sampling in the European Social Survey (ESS) took place. The discussion focused on design effects and inteviewer effects in face-to-face interviews. Following the recomendations of this meeting the Spanish ESS team studied the impact of interviewers as a new element in the design effect in the response’s variance using the information of the correspondent Sample Design Data Files. Hierarchical multilevel and cross-classified multilevel analysis are conducted in order to estimate the amount of responses’ variation due to PSU and to interviewers for different questions in the survey. Factor such as the age of the interviewer, gender, workload, training and experience and respondent characteristics such as age, gender, renuance to participate and their possible interactions are also included in the analysis of some specific questions like “trust in politicians” and “trust in legal system”. Some recomendations related to future sampling designs and the contents of the briefing sessions are derived from this initial research.