Development and psychometric properties of the interprofessional collaboration Practice Assessment Scale for primary care (Interprime Scale) in Indonesia

Interprofessional collaboration in primary care is increasingly recognized as essential for delivering effective care; however, robust and contextually appropriate instruments for Indonesian primary care remain limited. This study aimed to develop and validate the Interprofessional Collaboration Practice Assessment Scale for Primary Care (Interprime Scale). Instrument development involved four stages: construct definition, item generation, expert review and refinement, and psychometric evaluation. A cross-sectional survey was conducted among 825 health professionals from 104 primary health care centers in four districts/cities of South Sumatra Province, Indonesia. Content validity was assessed using item-level and scale-level content validity indices. Construct validity was examined through stepwise confirmatory factor analysis, and reliability was assessed using Cronbach's alpha. Following expert review and psychometric testing, 42 items were retained across 10 dimensions. The final model demonstrated satisfactory content validity and acceptable to excellent model fit. Internal consistency was high for the overall scale (Cronbach's α = 0.97), while the dimension-specific coefficients ranged from 0.83 to 0.93. The elevated overall coefficient may partly reflect the length of the 42-item scale and possible conceptual overlap among some items. These findings provide preliminary evidence supporting the reliability and construct validity of the Interprime Scale in Indonesian primary care settings.