Retrospective self-reports by clients differ from original reports: implications for the evaluation of drug treatment programs.

In a longitudinal study, 344 drug addicts in treatment described their status at three points in time: at treatment intake, and at 2 months and 8 months after intake. At the final interview they retrospectively described their prior status at treatment entry and 2 months after treatment entry. The retrospective reports were systematically more negative than the original reports in such areas as illicit behavior, sources of income, and life satisfaction. The results were interpreted in terms of an impression management explanation which suggests that clients distort their early self-presentations to access desired treatment services. A consequence of having artificially elevated pretreatment measures is that even if treatment is beneficial, elevated pretreatment measures may obscure true gains during treatment.