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Bias from Farmer Self‐Selection in Genetically Modified Crop Productivity Estimates: Evidence from Indian Data
Author(s) -
Crost Benjamin,
Shankar Bhavani,
Bennett Richard,
Morse Stephen
Publication year - 2007
Publication title -
journal of agricultural economics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.157
H-Index - 61
eISSN - 1477-9552
pISSN - 0021-857X
DOI - 10.1111/j.1477-9552.2007.00076.x
Subject(s) - selection bias , productivity , bt cotton , yield (engineering) , selection (genetic algorithm) , bacillus thuringiensis , crop , economics , genetically modified crops , crop yield , production (economics) , genetically modified organism , agricultural science , microbiology and biotechnology , agricultural economics , agronomy , biology , statistics , mathematics , microeconomics , computer science , biochemistry , materials science , genetics , transgene , artificial intelligence , bacteria , gene , metallurgy , macroeconomics
In the continuing debate over the impact of genetically modified (GM) crops on farmers of developing countries, it is important to accurately measure magnitudes such as farm‐level yield gains from GM crop adoption. Yet most farm‐level studies in the literature do not control for farmer self‐selection, a potentially important source of bias in such estimates. We use farm‐level panel data from Indian cotton farmers to investigate the yield effect of GM insect‐resistant cotton. We explicitly take into account the fact that the choice of crop variety is an endogenous variable which might lead to bias from self‐selection. A production function is estimated using a fixed‐effects model to control for selection bias. Our results show that efficient farmers adopt Bacillus thuringiensis (Bt) cotton at a higher rate than their less efficient peers. This suggests that cross‐sectional estimates of the yield effect of Bt cotton, which do not control for self‐selection effects, are likely to be biased upwards. However, after controlling for selection bias, we still find that there is a significant positive yield effect from adoption of Bt cotton that more than offsets the additional cost of Bt seed.