Assessing the Fidelity of Evidence-Based Practices: History and Current Status of a Standardized Measurement Methodology.

Evidence-based practices are effective only when implemented faithfully. This paper explicates the history, standardization, and methods for developing and validating measures of fidelity. We overviewed the past 20 years of developing fidelity measures, summarized standardization of the development procedures, and described needed psychometric assessments. Fidelity assessment has become the sine qua non of implementation, technical assistance, and research on evidence-based practices. Researchers have established standardized procedures for scale development and psychometric testing. Widescale use of fidelity measurement remains challenging. The implementation of evidence-based practice and the development and validation of fidelity measures are interdependent. International improvements of mental health care will require attention to both.