Latent structure and factor reliability of the National Health Service Community Mental Health Service User Questionnaire

Background National Health Service use the Community Mental Health Service User Questionnaire (NHS-CMH) to assess care quality. However, its reliability and internal validity is uncertain. Aims To test the NHS-CMH structure, reliability and item-level characteristics. Methods We used data from 11,373 participants who answered the 2017 NHS-CMH survey. First, we estimated the NHS-CMH structure using Exploratory Factor Analysis (EFA) in half of the dataset. Second, we tested the best EFA-derived model with Confirmatory Factor Analysis (CFA). We tested the internal validity, construct reliability (omega - omega), explained common variance of each factor (ECV), and item thresholds. Results EFA suggested a 4-factor solution. The structure derived from the EFA was confirmed, demonstrating good reliability for the four correlated dimensions: "Relationship with Staff" (omega = 0.952, ECV = 40.1%), "Organizing Care" (omega = 0.855, ECV = 21.4%), "Medication and Treatments" (omega = 0.837, ECV = 13.3%), and "Support and Well-being" (omega = 0.928, ECV = 25.3%). A second-order model with a high-order domain of "Quality of Care" is also supported. Conclusions The NHS-CMH can be used to reliably assess four user-informed dimensions of mental health care quality. This model offers an alternative for its current use (item-level and untested sum scores analysis).