CONCURRENT AND CONSTRUCT-VALIDITY OF THE OUTCOME QUESTIONNAIRE

The Outcome Questionnaire (OQ) was developed by Lambert and colleagues (1994) as a standardized measure for assessing psychotherapy outcome. Although the instrument is already being widely used in managed healt h care quality control, further evidence of its psychometric propertie s is needed. This research evaluated the concurrent and construct vali dity of the OQ with three patient samples and a sample of community pa rticipants. Support was found for the construct and concurrent validit y of the OQ with both patients (n = 183) and nonpatients (n = 210). Th e data show significant differences in scores between patients and com munity samples, as well as differences between the various clinical sa mples with varying levels of pathology. Although high correlations bet ween the OQ Total (and subscale) scores and the criterion measures wer e found, high intercorrelations among subscales suggest considerable s hared variance between subscales. The OQ Total score appears promising as a measure of general psychological distress, although further rese arch is needed to justify the interpretation of subscale scores in cli nical settings.