CSRDA Discussion Paper Series

No. 57 Development of a Japanese version of the work group inclusion scale using classical test theory and item response theory
Nobutada Yokouchi, Rie Fujisawa, Yoshiaki Takao‚ÄČ
Nobutada YokouchiThe University of Tokyo
Rie FujisawaRecruit Management Solutions Co.
Yoshiaki TakaoTokyo Metropolitan University
work group inclusionscale developmentvalidationitem response theoryJapanese employees
Goal 3: Good Health and Well-BeingGoal 5: Gender EqualityGoal 8: Decent Work and Economic Growth
Survey on work environments for diverse human resources, 2019

Work group inclusion has been recognized as a key to promoting the beneficial aspect of diversity; however, empirical studies based on sound measurement are limited in Japan. This study aimed to develop a Japanese version of the work group inclusion scale (WGIS-J) based on the original English scale. After multiple forward and back translations of the original scale, a cross-sectional survey was conducted with 1270 employees of a manufacturing corporate group located in Japan as part of an annual health survey (January 2022). The psychometric properties of the scale were assessed using 909 complete responses based on classical test theory and item response theory. The results supported the original two-factor model in which the belongingness and uniqueness subscales were allowed to correlate. Work group inclusion correlated significantly with hypothesized antecedents and outcomes in an anticipated manner, supporting the construct validity of the scale. Measurement precision was high for a wide range of latent variable levels. Although some items exhibited differential item functioning, the magnitudes were below the salience threshold. These findings demonstrated the good performance of WGIS-J for use with Japanese employees. Future studies should involve participants from different sectors, assess additional psychometric properties, and use other analytical models.