Evaluating the service quality in early intervention (EI) from the perspective of professionals with knowledge in this area is essential for the improvement of EI centres. In this study, we aimed to test the reliability and validity of the adapted Inventory of Quality in Early Intervention Centres-P (IQEIC-P) in a sample of professionals who worked in EI centres. Three hundred and twenty-four professionals of 85 EI Spanish centres were recruited for this research. Various psychometric analyses were used to evaluate the factorial structure, the internal consistency, factorial validity and construct validity. A 5-dimension structure was obtained in the exploratory factor analysis (EFA). The results showed an adequate internal consistency (Cronbach's alpha values between 0.71 and 0.83, and composite reliability (CR) values higher than 0.70), as well as satisfactory convergent and discriminant validity (average variance extracted (AVE) values above 0.50). In the confirmatory factor analysis, good model fit indicators were observed. The IQEIC-P showed adequate psychometric properties, demonstrating to be a valid instrument for the evaluation of service quality in EI centres from the perspective of professionals. The benefits will influence the professionals themselves, and they will have a positive and direct impact on the families that are attended to in these centres.
Keywords: early intervention; factorial structure; service providers; service quality; validity.