Melinda Smale
International Food Policy Research Institute (IFPRI).
Patricia Zambrano
International Food Policy Research Institute (IFPRI).
Mélodie Cartel
Ecole Nationale Supérieure d’Agronomie de Montpellier.

We assess 47 peer-reviewed articles that have applied stated economics methods to measure the farm-level impacts of Bt cotton in developing agriculture from 1996. We focus on methods, although findings are also contrasted and compared in qualitative terms. The central research question assessed by the articles reviewed is: what are the current and potential advantages of transgenic cotton with respect to yield, pesticide use, input cost, revenue and/or profits at the farm-level, by farm type, and geographical region? We find that, while the evidence is promising, the balance sheet remains inconclusive—in part because of some methodological limitations and in part because institutional and political context, which is mutable and often ignored, shapes economic impacts, especially over the longerterm. Most often, the contextual factors that influence whether a new variety succeeds or fails are more critical than whether yield advantages can be demonstrated in on-farm trials.

Key words: Bt cotton, developing economies, economic impact, literature review.