Development and Psychometric Validation of the Japanese Version of the Everyday Ageism Scale ( EAS ‐J) Among Older Adults

AIM: Japan lacks a validated tool to measure everyday ageism, leaving its prevalence and health impact unclear. This study aimed to develop and validate the Japanese version of the Everyday Ageism Scale (EAS-J) in older adults. METHODS: We used a mixed-methods design comprising forward and back translation, cognitive interviews, and a nationwide cross-sectional online survey of 1500 adults ages 60-79 years. In September 2025, participants were recruited from an online panel using quota sampling to reflect national demographic distributions. We evaluated psychometric properties using confirmatory factor analysis, reliability coefficients, and validity indices. A Multiple Indicators Multiple Causes model was used to assess associations with loneliness, stress, well-being, self-esteem, and happiness. RESULTS: The EAS-J demonstrated a three-factor structure-exposure to ageist messages, ageism in interpersonal interactions, and internalized ageism. Model fit was good on three of the four indices (comparative fit index = 0.971, Tucker-Lewis Index = 0.959, Root Mean Square Error of Approximation = 0.075, Standardized Root Mean Square Residual = 0.037). Internal consistency was good (Cronbach's α = 0.83), test-retest reliability was moderate (Intraclass Correlation Coefficient = 0.66), and convergent and discriminant validity were supported. The scale showed significant associations with perceived stress, loneliness, well-being, and self-esteem, supporting nomological validity. CONCLUSIONS: The EAS-J is a psychometrically supported, multidimensional instrument for measuring everyday ageism among older adults in Japan. Availability of the EAS-J will facilitate research on the prevalence and health consequences of everyday ageism and inform development of interventions to promote healthy aging.