The purpose of this paper is to assess the representativeness of the longitudinal surveys of Drug Addicts and Alcoholic (DA&A) Supplemental Security Income (SSI) recipients collected by various grantees commissioned by the Center on Substance Abuse Treatment (CSAT). CSAT commissioned grantees in seven catchment areas (in five states) to survey representative samples of DA&A "SSI-only" recipients (i.e., DA&A SSI recipients who did not receive additional disability benefits from Social Security Disability Insurance).

The findings indicate that the CSAT grantees across all sites were generally very successful in selecting and interviewing a representative sample of DA&A SSI-only recipients from their catchment areas. With perhaps surprisingly few exceptions, the characteristics of those in the CSAT respondents are closely matched to the characteristics of the target populations of DA&A recipients in the catchment areas and CSAT sample members. The authors do find that certain sites selected samples that were more representative of their catchment area than others. It is important to note, however, that the CSAT data are not representative of National DA&A SSI-only recipients. These differences largely reflect the characteristics of the populations of the catchment areas relative to the national population.