This study aimed to investigate the validity and reliability of the Japanese version of the Overwork Climate Scale. Japanese workers were invited to participate in online surveys at baseline and 1-month follow-up. The Overwork Climate Scale was translated into Japanese, according to international guidelines. Reliability was assessed using Cronbach's alpha and the intra-class correlation coefficient (ICC), while structural validity was evaluated through confirmatory factor analysis (CFA). Psychological job demands, work engagement, psychological safety, and workaholism were assessed for convergent validity. The number of respondents was 302 at baseline and 169 at follow-up. Results indicated robust Cronbach's alpha values of 0.86 (for overwork endorsement) and 0.80 (for lacking overwork reward) at baseline, complemented by ICC of 0.89 and 0.82, respectively. CFA confirmed the suitability of the two-factor model. Moreover, the Japanese Overwork Climate Scale exhibited significant correlations with anticipated constructs. Structural equation modeling revealed a consistent association between overwork climate and both workaholism and work engagement, similar to the original version. In conclusion, the Japanese version of the Overwork Climate Scale demonstrates acceptable levels of reliability and validity, warranting its potential adoption among Japanese workers.
Keywords: Cronbach’s alpha; Intra-class correlation coefficient; Japan; Long working hours; Overwork Climate Scale; Workers.