Development and testing of the First-Episode Psychosis Services Fidelity Scale

Objective: The purpose of this study was to test the reliability and validity of the First-Episode Psychosis Services Fidelity Scale (FEPS-FS) and compare it with similar scales. Methods: A fidelity scale was developed from previously identified essential components of first-episode psychosis services. The scale was tested in six programs in two countries and compared with three existing scales. Results: Program data collection from multiple sources indicated the feasibility and reliability of the FEPS-FS (intraclass correlation coefficient for interrater reliability=.842; 95% confidence interval=.795-.882). Satisfactory programs scored an average of 86% of the maximum total score; the single unsatisfactory program scored 70%. Compared with the other scales, the FEPS-FS has fewer items, but it has the highest proportion of items common to all scales. Conclusions: The FEPS-FS is a feasible, compact, reliable, and valid measure of adherence to evidence-based practices for first-episode psychosis services that can be applied to any first-episode psychosis service.