This special section presents the psychometric properties of fidelity scales used in a national mental health services project in Norway to improve the quality of care of people with psychoses. Across Norway, 39 clinical units in six health trusts participated. The project provided education, implementation support and fidelity assessments. The papers in the section address the psychometrics of fidelity measurement for the specific evidence-based practices: illness management and recovery, family psychoeducation, physical healthcare and antipsychotic medication management. Another paper analyzes the psychometrics of a scale measuring individualization and quality improvement that may be used in conjunction with fidelity scales for specific evidence-based practices. The first paper in the section presents the development and field of fidelity scales, and the two final papers with comments add some additional perspectives and discuss fidelity scales in a wider context. The psychometrics of the five scales were good to excellent. Fidelity assessment is a necessary and effective strategy for quality improvement.
Keywords: Evidence-based practices; Fidelity scales; Psychometrics; Psychosis.