The Use of Propensity Score Methods in Psychotherapy Research A Practical Application

A Bartak, MD Spreeuwenberg, Helene Andrea, Jan van Busschbach, MA Croon, R Verheul, PMG Emmelkamp, T (Theo) Stijnen

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Background: Randomized controlled trials are considered the best scientific proof of effectiveness. There is increasing concern, though, about their feasibility in psychotherapy research. We discuss a quasi-experimental study design for situations in which a randomized controlled trial is not feasible. Here, as an alternative strategy, the propensity score (PS) method is used to correct for selection bias. Methods: We used data from a Dutch research project, SCEPTRE (Study on Cost-Effectiveness of Personality Disorder Treatment). The sample consisted of 749 psychotherapy patients with personality pathology. We tested whether the PS method was useful and applicable. We examined differences between 2 treatment groups (short vs. long treatment duration) in pretreatment characteristics before and after PS correction. This revealed the impact of the PS on outcome differences. Results: The PS offered statistical control over observed pretreatment differences between patients in a non-randomized study. Conclusions: When a randomized controlled trial is not possible, this quasi-experimental design using the PS could be a feasible alternative. Its advantages and limitations are discussed. Implemented carefully, this method is promising for future effectiveness research. Copyright (C) 2008 S. Karger AG, Basel
Original languageUndefined/Unknown
Pages (from-to)26-34
Number of pages9
JournalPsychotherapy and Psychosomatics
Issue number1
Publication statusPublished - 2009

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