Drop-out rate as a performance indicator in psychotherapy.

Many large studies of psychotherapy show that the median patient drops out by the 5th session and most before the 10th session. Data from an effective behavior therapy clinic for the anxiety disorders showed that only 17% of patients failed to complete a median of 60 h of therapy. Patient characteristics were not associated with attrition. We examined 5 meta-analytic treatment reviews and found the median drop-out rate was 8% after 20 h of therapy. We suggest that low attrition is associated with effective, standardized treatment and as such, drop-out rate may be a proxy variable that can indicate effective service delivery.