The Portuguese version of the Outcome Questionnaire (OQ-45): Normative data, reliability, and clinical significance cut-offs scores

Abstract

ObjectivesThe Outcome Questionnaire (OQ-45) is one of the most extensively used standardized self-report instruments to monitor psychotherapy outcomes. The questionnaire is designed specifically for the assessment of change during psychotherapy treatments. Therefore, it is crucial to provide norms and clinical cut-off values for clinicians and researchers. The current study aims at providing study provides norms, reliability indices, and clinical cut-off values for the Portuguese version of the scale.MethodData from two large non-clinical samples (high school/university, N=1,669; community, N=879) and one clinical sample (n=201) were used to investigate psychometric properties and derive normative data for all OQ-45 subscales and the total score.ResultsSignificant and substantial differences were found for all subscales between the clinical and non-clinical sample. The Portuguese version also showed adequate reliabilities (internal consistency, test-retest), which were comparable to the original version. To assess individual clinical change, clinical cut-off values and reliable change indices were calculated allowing clinicians and researchers to monitor and evaluate clients' individual change.ConclusionThe Portuguese version of the OQ-45 is a reliable instrument with comparable Portuguese norms and cut-off scores to those from the original version. This allows clinicians and researchers to use this instrument for evaluating change and outcome in psychotherapy.