Performance in reducing child stunting in Africa: a stochastic frontier analysis of 54 countries over the past two decades (2000-2022).

INTRODUCTION: Africa remains off-track to meet 2030 stunting targets despite relative economic growth. We aimed to quantify the 'nutrition conversion gap', the efficiency with which national resources are translated into stunting reduction, and examine factors associated with technical inefficiency across 54 African nations. METHODS: This longitudinal panel study (2000-2022; N=1134 country-years) used stochastic frontier analysis to estimate a health production frontier, defined as the maximum achievable health production score (100-stunting prevalence). Inputs (gross domestic product (GDP) per capita, dietary adequacy and maternal education) were modelled as 3-year weighted moving averages. Technical inefficiency was modelled as a function of lagged diarrhoea incidence, electrification, urbanisation and political stability. RESULTS: Significant performance heterogeneity exists across the continent. High technical inefficiency (γ=0.976, λ=6.33) accounted for 97.6% of the observed nutritional disparities. Low GDP elasticity (β=0.042, p<0.001) suggests economic growth alone is an insufficient standalone strategy for stunting eradication. Senegal and Somalia achieved near-optimal efficiency despite low national wealth, whereas nations like Equatorial Guinea and Botswana exhibited high systemic inefficiency despite significant economic resources. Electricity access was significantly associated with a narrower conversion gap (p<0.001). Furthermore, political stability in the absence of institutional reform correlated with increased inefficiency (δ=0.39, p<0.001). CONCLUSION: Nutritional progress is profoundly decoupled from national wealth. Policy must pivot from aggregate resource accumulation towards mitigating systemic bottlenecks, specifically infection control and electrification. Strengthening health system efficiency through decentralised, community-led models represents a more potent roadmap for human capital development than simple macroeconomic expansion.