RESUMO
In many low- and middle-income countries blood donations per capita are substantially lower than in advanced economies. In these countries blood supply is mostly collected through directed donations from relatives and friends to individuals needing transfusions or to replace blood used in emergencies. The World Health Organization considers this method of blood supply inefficient compared to undirected voluntary donations. To examine methods to motivate undirected voluntary donations, we ran a large-scale, natural field experiment in Argentina, testing the effectiveness of information, social and financial incentives. We find that only higher-valued financial incentives generated more donations, increasing with the value of the reward. These incentives did not create adverse selection in the safety or usability of the donated blood. We discuss the implications of our findings for researchers interested in understanding motivations for pro-social behavior and for health agencies and policymakers concerned with the current and growing shortages in blood supply in low- and middle-income countries.