A systematic literature review of evidence on psychometric validation and reliability of 9-item shared decision-making questionnaire

Aim: This study aimed to provide comprehensive information on translated versions of the SDM-Q-9 questionnaire, which is widely used to measure patient involvement in shared decision-making, by combining psychometric validation information. Subject and Methods: We researched various databases, developer websites, and validated studies to gather pertinent information on item characteristics, content validity, and factor analysis. Our evaluation was based on predetermined cut-off values for item difficulty, discrimination index, Cronbach’s alpha, KMO, Bartlett’s test of sphericity, and factor extraction and rotation, CFA range. Results: The final analysis included eight studies with a total of 2934 participants from various countries and most participants had adequate literacy and age range was 30-60 years. Most model versions had a good fit and all studies reported satisfactory results, except for one study’s discrimination index values. The tool’s validity was satisfactory. Most of the studies reported convenient sample was the main limitation, along with recall bias in the final responses. Conclusion: The SDM-Q-9 tool can be used to measure patient involvement in shared decision-making in validated language-respected countries, as proper evaluation procedures reported satisfactory results in the confirmatory analysis models and reliability testing.