Many studies have been conducted to estimate the economic returns to society from public research investments aimed at achieving these productivity increases. A recent study found more than 1,700 distinct estimates of the returns to various research programs around the world.4 A summary of the results is presented in Table 12-2. Individual programs and projects vary widely in their estimated returns, but on the whole agricultural research has been a highly profitable investment for the societies that undertake it. Both mean and median annual ratesof return are well above government cost of capital, or earnings on alternative investments. National leaders have a responsibility to invest scarce public resources in activities that yield high returns.