Closing the Gap in Early Mathematics: Domain and Cognitive Insights from TIMSS 2023 in South Africa and Singapore

Background South Africa continues to underperform in primary mathematics, with persistent foundational gaps across content and cognitive domains. This study examines domain-specific patterns of mathematics achievement using data from the Trends in International Mathematics and Science Study (TIMSS) 2023, benchmarking South African Grade 5 learners against Singaporean Grade 4 learners. Methods A quantitative secondary analysis was conducted using nationally representative TIMSS 2023 datasets comprising 10,424 South African learners from 285 schools and 6,530 Singaporean learners from 181 schools. In TIMSS 2023, South Africa assessed learners in Grade 5 using the internationally standardised TIMSS Grade 4 mathematics assessment framework, a practice adopted within TIMSS where curriculum exposure aligns more closely with this level. Singapore assessed learners at Grade 4 using the same instruments. Mathematics achievement was analysed across content domains (number, measurement and geometry, and data) and cognitive domains (knowing, applying, and reasoning). Weighted estimates, mean differences, and effect sizes (Cohen’s d) were computed in line with IEA guidelines. Results South African learners performed well below the international centre point across all domains. The largest content-level gap relative to Singapore occurred in measurement and geometry, indicating persistent weaknesses in spatial reasoning. At the cognitive level, the most pronounced deficit was in the knowing domain, reflecting fragile mastery of basic facts and procedural fluency. Although performance in applying was comparatively stronger, limitations in foundational knowledge constrained progression to reasoning, particularly in non-routine problem-solving. Conclusions Weak foundations, underdeveloped spatial reasoning, and limited opportunities for higher-order thinking characterise early mathematics learning in South Africa. Targeted support for number fluency and geometry instruction, alongside pedagogical approaches that leverage application to scaffold reasoning, is required. Improved alignment between curriculum design, teacher development, and assessment practices is essential for advancing equitable foundational learning outcomes.