This paper reports on two surveys commissioned by the State of Missouri, Division of Drug and Alcohol Abuse, to begin the assessment of state supported treatment programs. The first survey, commissioned in 1989, was a retrospective study conducted a full year after the sample frame was discharged from treatment. The study was based primarily on client self-reports gleaned from a telephone survey. The process and products of this study led to substantial changes in the methodology employed in an ongoing three-year prospective study commissioned in 1991. This paper will discuss the results of the original survey, detail how this experience has shaped the prospective study, arid briefly compare preliminary data, particularly response rates and the representativeness of the two samples.