Longitudinal Surveys: Issues and Opportunities
Longitudinal or panel surveys, in which the same individuals are interviewed repeatedly over time, are increasingly common in the social sciences. The benefit of such surveys is that they track the same respondents so that researchers can measure individual-level change over time, offering greater causal leverage than cross-sectional surveys. Panel surveys share the challenges of other surveys while also facing several unique issues in design, implementation, and analysis. This chapter considers three such challenges: (1) the tension between continuity and innovation in the questionnaire design; (2) panel attrition, whereby some individuals who complete the first wave of the survey fail to participate in subsequent waves; and (3) specific types of measurement error—panel conditioning and seam bias. It includes an overview of these issues and their implications for data quality and outlines approaches for diagnosing and correcting for these issues in the design and analysis of panel surveys.
