Abstract
As adolescent socialization and civic participation increasingly migrate to digital ecosystems, assessing digital citizenship with psychometrically robust and culturally sensitive instruments has become imperative. This study reports on the development and cross-cultural validation of the Multidimensional Adolescent Digital Citizenship Scale (MADCS), evaluated across secondary school cohorts in Seoul, South Korea (n = 1,124), Taipei, Taiwan (n = 1,088), and Tokyo, Japan (n = 1,156). Drawing on an integrative framework encompassing critical information literacy, online civic engagement, digital ethics and empathy, and algorithmic awareness, the initial 32-item pool was refined via exploratory and confirmatory factor analyses to a robust 20-item, four-factor structure. Multigroup confirmatory factor analysis supported full metric and partial scalar invariance across all three regional cohorts, confirming the instrument's structural stability. Criterion-related validity was established through meaningful correlations with global civic mindedness, prosocial behavior, and verified online political participation, while discriminant validity was confirmed against generalized internet addiction measures. The findings indicate that while digital empathy and algorithmic literacy vary modestly across socio-technological environments, the underlying construct of digital citizenship remains invariant. The MADCS provides researchers, educators, and policymakers with an empirically validated, cross-nationally comparable measurement model designed to advance evidence-based digital literacy curricula and youth digital equity initiatives.