Supplementary Material for: A Self-Reported Version of the Measurements in the Addictions for Triage and Evaluation-Q: Concurrent Validity with the MATE 2.1

Introduction: Substance abuse treatment centers require reliable and valid instruments to monitor treatment progress, to evaluate treatment effectiveness, and to initiate clinical trials. Currently the Measurements in the Addictions for Triage and Evaluation (MATE) 2.1, an instrument that serves these purposes, is considered quite lengthy and intensive, especially in the case of allocation to milder treatment intensity. Therefore, a self-reported version of the MATE-Q was designed for patients with mild to moderate substance-abuse and co-occurring problems. The aim of the present study was to assess concurrent validity with the interviewer version of the MATE (version 2.1). Materials and Methods: Data were collected at 2 locations of a Dutch substance abuse treatment center, one location in a large city and one in a suburban area. A correlational design was employed, where each included participant completed a MATE-Q and a MATE 2.1 within 3 days or less (administered at intake, before treatment initiation). A total of 98 treatment-seeking patients were included (51.0% alcohol as a primary problem, 19.4% cannabis, 14.3% gambling and 6.1% cocaine). Measurements included the MATE-Q and the MATE 2.1. Intraclass correlation coefficients (ICCs) for single measures were calculated, deploying the 2-way mixed procedure with absolute agreement. Descriptives of scores comprise means and Cronbach’s alpha for internal consistency. Results: For the majority (15 out of 24) of the scores ICCs were equal or above 0.7. For 93 patients (95%), the primary problem substance or problem behavior was reported correspondingly. Nine MATE-Q mean scores differed significantly from their MATE 2.1 counterparts. Discussion/Conclusion: For the majority of scores, the MATE-Q has acceptable concurrent validity for the assessment of patients with mild to moderate substance abuse and co-occurring problems.