This working paper critically examines the evidence base for cognitive gains from early childhood development (ECD) interventions in South Africa, challenging assumptions often derived from the global Heckman Curve investment case. While international literature strongly supports early investment for long-term benefits, local data reveal gaps in demonstrating significant cognitive improvements attributable to ECD programmes. The paper analyses results from large-scale assessments using the Early Learning Outcomes Measure (ELOM) and compares programme participants against counterfactuals to estimate value-added learning gains. Findings suggest that while some interventions show modest improvements in language and numeracy, overall effects are smaller than expected, raising questions about programme quality, dosage, and contextual factors such as poverty and home environments. The study calls for more rigorous evaluations, better alignment between programme design and developmental benchmarks, and investment in practitioner training to enhance effectiveness.
