For this study researchers wanted to evaluate the reliability and validity of the Rosser categorization system for illness stages in patients with musculoskeletal diseases in Spanish. A questionnaire validation design was used in this investigation. Patients were seen at a rheumatology outpatient clinic at Hospital Clinico San Carlos in Madrid, Spain. The Rosser categorization system was completed by the study team’s physician (PMQ) and the patient (HMQ). The EuroQol-5D for the HMQ and the physician global estimate (DOCGL) for the PMQ serve as criterion standards. Cronbach’s alpha was used to determine internal consistency dependability. The intraclass correlation coefficient was used to assess test-retest and interobserver reliability. The Spearman correlation coefficient was used to analyze the criterion validity of HMQ and EuroQol-5D, as well as PMQ and DOCGL.

The whole research was based on four patient samples (104 to 266 individuals), the majority of whom were middle-aged women. Cronbach’s alpha for HMQ was 0.70. The repeatability of the test-retest was 0.7. Significant relationships in the predicted direction were found for criteria validity. Cronbach α for PMQ was 0.70, suggesting strong intraobserver and interobserver reliability. In terms of criteria validity, the PMQ and the DOCGL showed high connections.

For individuals with musculoskeletal problems, the Rosser classification system demonstrated acceptable reliability and criteria validity. The tool appeared to be appropriate for clinical decision-making and research.