RESUMEN
The study aimed to validate the Jenkins Sleep Scale (JSS-4) in six Spanish-Speaking countries. A total of 1726 people participated and were distributed between men (32.4%) and women (67.6%). Confirmatory factor analysis confirmed the unidimensional structure and high reliability of the JSS-4 overall (α = 0.85, ω = 0.81) and within each country. The invariance analysis revealed that JSS-4 exhibited complete invariance across countries, thus establishing a robust foundation for inter-group comparisons. Interestingly, a comparative analysis revealed significant differences in the average levels of sleep difficulties, with particularly high rates in Spain and Chile. Item Response Theory (IRT) showed sufficient discrimination parameters for all items, and a correlation of 0.998 between Confirmatory Factor Analysis (CFA) and IRT highlighted the robustness and reliability of the results obtained. In summary, JSS-4 exhibits strong evidence of validity and consistency in measurement invariance across the six countries.
