The questionnaire consists of the core questions from the European Social Survey in which a Multi Trait Multi Method (MTMM)-experiment was incorporated. Each MTMM experiment consisted of three questions (traits) and one repetition of the same questions in a different form at the end of the questionnaire. Since the order in which the different forms of the questions are asked may make a difference for the quality estimates of the questions, a three group Split Ballot MTMM design was used for each topic.