Social sector development

The social sector — health, education, nutrition, water, sanitation and social protection — builds human capabilities directly. Its economics is distinctive: benefits spill over (an educated, healthy population raises everyone's productivity), private markets underprovide it (the poor cannot pay, benefits are partly external), and outcomes depend on public delivery quality, not just spending. Worked example: if a vaccination programme costs 10 per child and prevents illness worth 40 per child in treatment costs and lost work, its benefit-cost ratio is 4:1 — but private clinics may still underprovide it, because much of the benefit (herd immunity) goes to others.