These studies have all utilized interview-based assessment that depend for their validity on subject cooperation, and accurate recall and reporting of behavior that is typically socially sanctioned and sometimes illegal. Prior surveys have suggested that externalizing behaviors are associated both with lowered rates of cooperation and greater attrition in longitudinal studies (Cox et al. 1977; Eaton et al. 1992; Heath et al. 1998; Karp et al. 1993; Robins 1966).
