The Follow-up project Psychotherapeutic Communities bears heavily on a newly constructed self report instrument - namely the `Nieuwkoopse Vragenlijst' (NVL). That is why a thorough investigation into the validity of the self-report statements had to be carried out. This article describes such an effort to examine the concurrent and predictive validity of the questionnaire at issue. Readmission in a period of six years after discharge from the community was chosen as external criterion. The results support the concurrent validity of the follow-up versions of the questionnaire and the predictive validity of the discharge version. The differences at discharge show a consistent and clinically relevant picture.