Objective: Standardized instruments are widely used to assess homeless persons, but basic data on their reliability and validity in these populations have not been available. The purpose of this study was to examine the reliability of standardized instruments used in a cooperative agreement on homeless persons with substance use disorder.
Method: This study examined the 1-week test-retest reliability of the Alcohol Dependence Scale, the Addiction Severity Index and the Personal History Form, using 189 randomly selected subjects participating in a multisite study of services for homeless persons with alcohol and other drug abuse problems. In addition to scales and items, factors hypothesized to influence reliability related so subject, interviewer and setting were examined.
Results: Results showed substantial reliability for scale scores (> .60) but mixed reliability for individual items. Reliability was greater when items were factual and based on a recent time interval, and when subjects were interviewed in a protected setting. Higher reliability was also related to younger age, female gender, a first episode of homelessness and lower severity of psychiatric problems.
Conclusions: Reliability should be examined in individual studies of homeless persons, and efforts should be made to minimize controllable sources of unreliability.