Methodology of Longitudinal Surveys

Abstract

In this chapter, our focus is on panel conditioning with respect to attitude questions. Our methodological approach is different from the majority of previous studies in this area, in that we do not attempt to estimate biases in marginal and associational distributions through comparison with a fresh cross-sectional sample. Rather, our approach is based on testing hypotheses on a single dataset, derived from an explicit theoretical model of the psychological mechanism underlying conditioning effects in repeated measures of the attitude. We refer to this theoretical account as the cognitive stimulus (CS) model. Specifically, we use a range of empirical indicators to evaluate the theory that repeatedly administering attitude questions serves to stimulate respondents to reflect and deliberate more closely on the issues to which the questions pertain. This, in turn, results in stronger and more internally consistent attitudes in the later waves of a panel. The chapter proceeds in the following manner. First, we review the existing literature on panel conditioning effects. Next, we set out in more detail the rationale underlying the CS hypothesis.We then use data from the first ten waves of the British Household Panel Study (BHPS) to test four inter-related hypotheses expressed as empirical expectations of the CS model. We conclude with a discussion of the implications of our findings for the validity of attitude measures in panel surveys.