Understanding the Mechanism of Panel Attrition

Abstract

Nonresponse is of particular concern in longitudinal surveys (panels) for several reasons. Cumulative nonresponse over several waves can substantially reduce the proportion of the original sample that remains in the panel. Reduced sample size increases the variance of the estimates and reduces the possibility for subgroup analysis. Also, the higher the attrition, the greater the concern that error (bias) will arise in the survey estimates. The fundamental purpose of most panel surveys is to allow analysts to estimate dynamic behavior. However, current research on attrition in panel surveys focuses on the characteristics of respondents at wave 1 to explain attrition in later waves, essentially ignoring the role of life events as determinants of panel attrition. If the dynamic behaviors that panel surveys are designed to examine are also prompting attrition, estimates of those behaviors and correlates of those behaviors may be biased. Also, current research on panel attrition generally does not differentiate between attrition through non-contacts and attrition through refusals. As these two source of nonresponse have been shown to have different determinants, they can also be expected to have different impacts on data quality. The goal of this research is to examine these issues. Data for this research comes from the Panel Survey of Income Dynamics (PSID) conducted by the University of Michigan. The PSID is an ongoing longitudinal survey that began in 1968 and with a focus on the core topics of income, employment, and health.