The Relationship of Scientific Objectives to Population Selection and Attrition in Longitudinal Studies The Case of the Normative Aging Study

Abstract

A low attrition rate was found to be largely due to the selective nature of the population, in turn a result of special scientific objectives in the long-term longitudinal Normative Aging Study of the Veterans Administration. In addition, the attrition group was similar to those who remained. The original population characteristics have thus been maintained since inception of the Study in 1963. The problem of attrition in longitudinal studies should therefore be viewed in the broader context of scientific objectives.