The retention of older respondents in a longitudinal study is of important concern to data quality and representativeness of the target population. Participant non-response has been considered a more serious problem among older persons than among younger ones, since dropouts in longitudinal studies of older adults have been reported to be less…

A study with follow-up interviews of services for homeless and mentally ill persons (original sample of 163) had a very high success rate of over 70% in tracking this difficult to locate population. Techniques for locating clients are presented, as identified by a focus group of five researchers. (SLD)

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)