In a world characterized by a formal global consensus on norms of "Education for All," countries face growing social pressures to rationalize their educational institutions around a global and standardized set of best practices. In this context, I argue that national assessments are part of a more general set of organizational structures that measure and evaluate a country's progress toward achieving the goals of Education for All; however, they also specifically reflect commitments to expanded conceptions of student personhood that develop from longer-term processes of rationalization around an ontology of liberal individualism. Using an original data set of 132 countries, from 1960 to 2011, I show that national assessments have expanded rapidly after 1990, especially at the primary-school level. Results from event history analyses indicate that the adoption of a country's first national assessment test is shaped by its linkages to international nongovernmental organizations, the World Bank, and its education research output. Countries that maintain institutional structures that reflect older logics of educational selection and stratification are less likely to adopt a national assessment.