Making School-Set Assessments Comparable: Test Difficulty and Hidden Learning Inequality
PhD Candidate in Economics
Tinbergen Institute
Vrije Universiteit Amsterdam
Stellenbosch University
Job market paper, October 2026.
Paper (PDF) · Online appendix (PDF) · Online appendix (HTML) · World Bank blog post
Abstract
Assessment has been found to raise learning system-wide where its results can be compared across schools, yet at most a quarter of countries test every primary-school leaver comparably. I recover comparable learning outcomes, without a new test, from assessments that are incomparable because their difficulty varies across schools. Because students sit their secondary school’s assessments within months of arriving, I can compare primary schools through students who share a secondary school, and secondary schools through students who share a primary school. Two-way fixed effects chain these comparisons from 1.2 million South African students into grades that are comparable across schools. The gap between rich and poor schools halved on raw grades between 2018 and 2022 but did not narrow on comparable grades. Re-ranked on comparable grades, about three-quarters of primary schools change learning quintile. Comparable grades predict the national secondary leaving examination better than raw grades. Easier assessments do not buy a higher-achieving secondary school: at the same raw grade, students whose primary school set easier assessments join lower-achieving peers. Comparable grades on entry to secondary school are a necessary condition for measuring a secondary school’s value added.