Factorial structure and measurement invariance of the Italian version of the Cooper – Norcross Inventory of Preferences (C-NIP)

Abstract There is increasing evidence that psychotherapy efficacy can be enhanced by accommodating clients’ preferences regarding their role, the treatment, and the therapist. Several instruments are available to measure these concepts, although only the Cooper-Norcross Inventory of Preferences (C-NIP) appears particularly suitable for psychotherapy. This study aimed to validate the Italian version of the C-NIP and to provide norms for both clinical and research use for Italian-speaking individuals. We adopted a multi-step procedure to translate the C-NIP into Italian. Then, 1084 (70.3% females; M age = 27.22 ± 11 years) Italian adults completed an online survey. Psychometric properties of both the original C-NIP and a revised, 15-item, five-scale version of this questionnaire were analysed through a Confirmatory Factor Analysis (CFA), McDonald’s omega coefficients, mean inter-item correlations, measurement invariance, and Pearson correlations. The Italian translation of the original version of the C-NIP scales did not show good psychometric properties. However, the CFA on a revised factorial structure of the C-NIP evidenced adequate fit to the data. We found good support for the unidimensionality of all scales, but only one of the scales demonstrated an acceptable internal consistency. Measurement invariance was confirmed across both patient sex and across individuals who were and were not in psychotherapy. Results showed that the revised version of the C-NIP has satisfactory factorial structure for use with Italian adults. More research is needed to investigate how preferences vary over time and in relation to psychopathologies and client characteristics.