Psychometric properties of the outcome questionnaire-45.2: the Norwegian version in an international context

Monitoring of ongoing psychotherapy is of crucial importance in improving the quality of mental health care by detecting therapies being off track, which requires that the instrument used is psychometrically sound. This study investigates the psychometric properties of the Norwegian version of the Outcome Questionnaire 45.2 (OQ-45) and situates the results in an international context.

Data from one non-clinical sample (N = 338) and one clinical sample (N = 560) were compared to international samples investigating reliability, cut-offs, and factor structure.

The results show adequate reliability and concurrent validity.

The means, clinical cut-offs, and the reliable change index vary across countries. However, the means of the OQ-45 for nonclinical samples correlate highly with external values of national well-being, indicating that the OQ-45 is a valid instrument internationally. The factor analyses in the present study do not confirm the hypothesized factor structure of the OQ-45, but are similar to the results internationally.