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