Informationsverfügbarkeit und Response-Effects:

Respondents� self reports about the frequency or duration of certain activities are often found to be influenced by differences in the categorisation of substantially identical response scales. The cognitive availability of the information to be recalled is supposed to be the pivotal determinant of this type of response-effect. In the following article this hypothesis is tested, first of all, by analysing individual differences in the interviewees� response certainty and the response latencies needed to answer the focal question. Secondly, the predictive power of these two indicators of information availability for the existence of the response-effects under investigation is compared. Another open question addressed in this paper is how response latencies should be transformed prior to data analysis in order to maximise their accuracy in predicting response-effects. For this purpose, the validity of three transformations proposed in the literature with those of raw response-latencies is compared. Data from a local survey based on a random probability sample is used to answer these questions. The results show that both, response certainty and response latencies, are able to predict response scale effects on the reported television consumption. However, response latencies proved to be the much stronger predictor. A comparison of differently transformed versions of the response latencies reveals that difference-scores between the target response laten-cies and the individual interviewees� mean response speed during the rest of the interview is the best predictor for their susceptibility to the investigated response-effect.