Translation, cross-cultural adaptation and psychometric properties of the Jenkins Sleep Scale in a sample of Portuguese shift workers

The aim of this study was to translate the Jenkins Sleep Scale into Portuguese, to culturally adapt it to the Portuguese culture and to assess its stability, internal consistency and convergent validity among shift workers. The scale was validated in a random sample of 456 shift workers. The original Jenkins Sleep Scale was translated and culturally adapted to the Portuguese Culture using recommended procedures. The psychometric methods used were confirmatory factor analysis using structural equation modeling, Cronbach’s α coefficients, and intra-class correlation coefficients. The results suggest the JSS-PT has a single factor model, as the original version. The Comparative Fit Index and the Tucker-Lewis Index suggest an excellent fit. However, the relatively large sample size and the small number of items penalized c2 statistics and Root Mean Square of Error Approximation. Cronbach’s α coefficient was 0.839 for the extracted factor. Pearson bivariate correlations were performed on 75 participants, with an interval of 1 week for test-retest purposes with intra-class correlation of 0.989 (p < 0.01). Convergent validation showed significant correlations (r=0.570). The validity and reliability of this scale was established, enabling it to be used within the Portuguese language speakers. Nevertheless, this study should be replicated in other samples and other forms of validity might be explored.