More than 50 years ago, a revolution in seed and fertilizer technology bolstered food production and economic well-being in Asia and Latin America.

Unfortunately, this "Green Revolution" left sub-Saharan Africa behind. At the turn of the 21st century, many farmers still were struggling to produce enough food to feed their communities.

Then, in 2006, a number of African nations embarked on an ambitious plan to invest billions of dollars into their own green revolution.

In a paper in the American Economic Journal: Applied Economics, University of Michigan economist Dean Yang and co-authors Michael Carter and Rachid Laajaj examine the effectiveness of a temporary subsidy program in Mozambique. Running a randomized control trial, they found that giving farmers one-time vouchers for seed and fertilizer led to an immediate improvement in crop yields. And as word spread, other farmers not involved in the program got on board and amplified the effects ten-fold.

Yang spoke with the AEA's Chris Fleisher about that experiment in Mozambique, what it revealed about the impact of temporary subsidies, and how RCTs--considered the gold standard in experimental research—could still be improved.