On  November 4th voters in Colorado rejected a ballot initiative that would have required special labels for foods made with genetically modified (GM) ingredients. As The Economistwent to press, voters in Oregon seemed likely to say no to a similar proposal there, though the count was not complete. Regardless of the outcome, however, the referendums indicate the strength of feeling generated by GM crops: the Oregon vote was the costliest ballot in the state’s history.

By chance, the day before the poll saw the publication in PLOS ONE of the largest review yet conducted of the crops’ effects on farming. It concludes that these have been overwhelmingly positive.

The review in question is a meta-analysis. This is a statistically rigorous study of studies, rather than a mere summary of the literature. Its authors, Matin Qaim and Wilhelm Klümper, both of Göttingen University, in Germany, went through all examinations of the agronomic and economic impacts of GM crops published in English between 1995 and March 2014. This provides a near-complete survey. Most studies of the subject have been published in English, and the widespread adoption of such crops began only in the mid-1990s.

For the full article from The Economist, please click here.

The full study can be found here.