Abstract

SILVA, Sonia Maria da et al. Outcome Questionnaire (OQ-45.2): assessment of the psychometric properties using bifactor model and IRT. Psico (Porto Alegre) [online]. 2016, vol.47, n.4, pp. 298-308. ISSN 1980-8623.  http://dx.doi.org/10.15448/1980-8623.2016.4.24600.

The aim of this study was to evaluate the Psychometric properties of the Brazilian version of the Outcome Questionnaire (OQ-45.2), an instrument that assesses the progress of patients in psychotherapy. The adjustments of different measure models proposed to OQ-45.2 were compared through Confirmatory Factor Analysis, and the parameters of items and participants were estimated through the Andrich's rating scale model. The sample comprised 419 adults (mean age: 32.18±14.3; 62.8% women). The results demonstrated the suitability of the bifactor model with three specific factors (subjective discomfort, interpersonal relationships and performance in social roles) and a general factor (overall maladjustment) when compared to others in the literature, like the one-factor and the three related factors models. It was observed a model invariance of the OQ-45 internal structure for both men and women assessment. Regarding the items' properties (adjustment and difficulty) were obtained the appropriate psychometric parameters for the assessment of psychotherapeutic outcome. In conclusion, the OQ-45 is an appropriate measure tool for assessing these characteristics in Brazilian population.

Keywords : Item Response Theory; Factorial analysis; Psychological assessment; Test validity; Psychotherapy.

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