Educational attainment is the highest level of formal education successfully completed by an individual or group, typically indicated by credentials such as certificates, diplomas, or degrees, and sometimes by years of schooling ^[1][2][3][4]. It refers to the cumulative outcome of participation and progression in education systems—across primary, secondary, and tertiary levels—and is recorded using standardized categories (e.g., upper‑secondary completion, bachelor’s degree, postgraduate qualification) ^[1][2]. Educational attainment is characterized by its role as a structural indicator of educational success over the life course, distinguishing completion of recognised programmes from partial participation or non‑completion, and is widely used in analyses of social mobility, labour‑market outcomes, health, and inequality ^[2][3][4]. Within educational research and policy, educational attainment denotes a core measure of human capital and educational opportunity, where distributions and gaps in attainment across demographic or socio‑economic groups are examined to assess the fairness and effectiveness of education systems and related policies ^[1][2][3][4].