Abstract:
Nearly 200 million children under five in low- and middle-income countries face developmental deficits, even as access to early childhood services expands. We present evidence from a large-scale randomized controlled trial (N=3,131 children in 201 schools) in Nepal's government system testing three models of combining classroom quality with parental engagement. All teachers completed a 15-day training on pedagogy, national standards, and caregiver engagement, after which schools were randomly assigned to models varying whether caregiver sessions were led by teachers alone, by teachers supported with in-class helpers, or by external facilitators. The intervention increased children's developmental outcomes by 0.10–0.20 standard deviations and improved caregiver engagement by similar magnitudes. Effects were most consistent when teachers received support that sustained classroom quality while engaging families, underscoring the critical role of workload management. Impacts were concentrated among disadvantaged households—those with lower baseline engagement, higher stress, and less education—highlighting the potential to reduce early childhood inequalities. Mechanism analysis shows the program shifted home and school inputs from substitutes to complements, creating mutually reinforcing pathways for child development. These findings demonstrate that modest, system-embedded reforms can generate scalable improvements in early childhood human capital formation.