Internal Consistency and Test–Retest Reliability of the Jenkins Sleep Scale Across International Versions: A Reliability Generalization Meta-analysis

The Jenkins Sleep Scale (JSS) is a widely used self-report measure for assessing sleep difficulties. While the original English version of the JSS has demonstrated sound psychometric properties, research on translated versions is limited. We conducted a reliability generalization meta-analysis to systematically review and quantify the internal consistency and test–retest reliability of the JSS across all available translations. A systematic literature review identified k = 12 studies involving 90,173 participants reporting reliability statistics for eight different language versions of the JSS. Random-effects meta-analysis found acceptable mean internal consistency (α = 0.80) and excellent test–retest reliability (r = 0.93) across translations. Moderator analyses revealed that participant characteristics and demographics did not affect the results. The findings support the cross-language utility of the scale but highlight the importance of high-quality translation procedures, particularly when assessing stability over time. Recommendations are provided to guide future worldwide adaptation, validation, and clinical use of the JSS.