Estimating the direct and indirect effects of improved seed adoption on yields: Evidence from DNA-fingerprinting, crop cuts, and self-reporting in Ethiopia
中文摘要
农户采用改良作物品种可提高低收入国家的产量。然而，家庭调查中测量误差的存在对估计真实回报构成了挑战。利用2018/19年埃塞俄比亚社会经济调查，我们分析了三种测量误差来源（即对种子品种、土地面积和收获量的误判）如何影响玉米产量与投入品使用。这些数据包括种子的DNA指纹鉴定、GPS地块面积信息以及作物实割，我们将其与农户对这些指标的自报估计进行比较。结果表明，自报种子品种采用中的测量误差，尤其是来自不知道自己正在使用改良玉米品种的农户的误差，使估计的产量增益平均衰减了25个百分点。改良种子品种的遗传优势使产量较非改良品种增加了41*个百分点，而投入品使用的增加平均为改良品种带来了30个百分点的增益。
Abstract
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.