A Meta-Analysis of the Impacts of Genetically Modified Crops

Despite the rapid adoption of genetically modified (GM) crops by farmers in many countries, controversies about this technology continue. Uncertainty about GM crop impacts is one reason for widespread public suspicion.

We carry out a meta-analysis of the agronomic and economic impacts of GM crops to consolidate the evidence. DATA SOURCES: Original studies for inclusion were identified through keyword searches in ISI Web of Knowledge, Google Scholar, EconLit, and AgEcon Search. STUDY ELIGIBILITY CRITERIA: Studies were included when they build on primary data from farm surveys or field trials anywhere in the world, and when they report impacts of GM soybean, maize, or cotton on crop yields, pesticide use, and/or farmer profits. In total, 147 original studies were included. SYNTHESIS METHODS: Analysis of mean impacts and meta-regressions to examine factors that influence outcomes.