In the context of cross-sectional surveys, the scope of research on the impact of response enhancing strategies on sample composition and nonresponse bias is vast. This topic has rarely been addressed for panel studies, however, although these are becoming an increasingly important data source in social research. In this article, we evaluate the…

Arguing that reliable and valid dropout rate estimates are prerequisite to establishment of causal factors and intervention programs, this article examines differences in definitions of dropouts, computational methods, and the complexities in defining cohorts, as well as the importance of sample attrition. Several sources of error are discussed.…

Simple methods for detecting attrition (nonresponse) in longitudinal evaluations are reviewed, focusing on regression-based analyses of data from a longitudinal evaluation. The approaches are illustrated with data from the Fort Bragg Evaluation, an evaluation of a major demonstration in children's mental health services. (SLD)

Methods used to follow, for 18 months after pregnancy resolution, 241 premaritally pregnant urban adolescents in a longitudinal drug use study are described. One respondent dropped out after the first interview. Temporary attrition at each data collection wave was between 1 percent and 3 percent. Sample recruitment and retention are discussed.…

A general interest in attrition, or loss of units from a study, stems in part from the observation that the infrequency of attention to attrition exacerbates problems of data interpretation. As a substudy of the national evaluation of Project Follow Through, the potential biasing effects of attrition of subjects from the sites were investigated.…