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

Paulo P.P. MacHado, Daniel B. Fassnacht

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


Objectives The 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. Method Data 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. Results Significant 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. Conclusion The 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. Practitioner points This study provides norms for non-clinical and clinical Portuguese samples and investigates the reliability (internal consistency and test-retest) of the OQ-45. Cut-off values and reliable change index are provided allowing clinicians to evaluate clinical change and clients' response to treatment, monitoring the quality of mental health care services. These can be used, in routine clinical practice, as benchmarks for treatment progress and to empirically base clinical decisions such as continuation of treatment or considering termination.

Original languageEnglish
Pages (from-to)427-437
Number of pages11
JournalPsychology and Psychotherapy: Theory, Research and Practice
Issue number4
Publication statusPublished - 1 Dec 2015
Externally publishedYes


  • Norms
  • OQ-45
  • Outcome Questionnaire


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