Do lower yielding farmers benefit from Bt corn? Evidence from instrumental variable quantile regressions

There have been serious questions about whether lower-yielding farmers in developing countries, who are typically poor smallholders, benefit from genetically-modified crops like Bacillus thuringensis (Bt) corn. This article examines this issue by estimating the heterogeneous impacts of Bt corn adoption at different points of the yield distribution using farm-level survey data from the Philippines. A recently developed estimation technique called instrumental variable quantile regression (IVQR) is used to assess the heterogeneous yield effects of Bt corn adoption and at the same time address potential selection bias that usually plague impact assessment of agricultural technologies. We find that the positive yield impact of Bt corn in the Philippines tend to be more strongly felt by farmers at the lower end of the yield distribution. This result suggests that Bt corn could be a “pro-poor” technology since most of the lower-yielding farmers in the Philippines are poor smallholders with low incomes.