Estimating the direct and indirect effects of improved seed adoption on yields: Evidence from DNA-fingerprinting, crop cuts, and self-reporting in Ethiopia

Farmers’ adoption of improved crop varieties could increase yields in low-income countries. However, the presence of measurement error in household surveys poses a challenge to estimating true returns. Using the 2018/19 Ethiopia Socio-economic Survey, we analyze the impacts of how three sources of measurement error: misperceptions of seed varieties, land area, and quantities harvested affect maize yields and input use. These data include DNA-fingerprinting of seed, GPS plot size information, and crop cuts that we compare to farmers’ self-reported estimates of these measures. Results indicate that the measurement error in self-reported seed variety adoption, especially from farmers who did not know they were using improved maize varieties, attenuates their estimated yield gains by 25 percentage points on average. The enhanced genetics of improved seed varieties accounts for a 41-percentage point yield increase over non-improved varieties, and increased input use accounts for a 30-percentage point gain for improved varieties on average. JEL classification: D13, O13, N57, Q12, Q16

Adoption or placement in foster care and catch-up in linear growth and development: A meta-analysis of individual participant data

Background The ability of children to recover from linear growth retardation, often referred to as catch-up growth, has intrigued researchers for many decades. Whether adoption from a low-to a high-income setting, which provides a comprehensive improvement in the conditions that cause children to not grow well, leads to catch-up growth is unknown. Objective We estimated the association of adoption (or placement in foster care) with catch-up in linear growth and child development before 5 years of age. Methods We conducted a two-stage meta-analysis using individual participant data for linear growth. We obtained study-specific and subgroup estimates and pooled the estimates using random-effects models. Sensitivity analyses were used to assess the robustness of our findings. A review of child development outcomes was conducted. Results We included 485 children under 5 years of age from 9 adoption studies. At baseline, children had a mean age of 15.8 mo and a length deficit of 3.9 cm. Adoption reduced this gap by 77% or 3.0 cm (95% CI: 1.9-4.1 cm)(mean age 32.3 mo). Catch-up growth was found in both girls (3.6 cm; 95% CI 2.9-4.2 cm) and boys (2.5 cm; 95% CI: 1.9-3.1 cm) and in children adopted after the age of 24 mo (2.2 cm, 95% CI 0.6-3.7 cm). The sensitivity analyses did not change any of the substantive findings. The magnitude of catch-up in child development (mean reduction in deficit of 46%) was smaller than in linear growth. Conclusions Catch-up in linear growth in children under five is biologically possible when the environment is improved profoundly and comprehensively. Partial reversal of the accumulated height deficit was more likely than recovery in developmental outcomes which highlights the need to ensure all children grow and develop in environments that prevent deficits from occurring rather than trying to correct them.

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