Matching-Gift Incentives and Blood Donation: Linking Local and Global Altruism

We conducted a large-scale field experiment in Granada, Spain, to assess the motivating effect on blood donation of matching each attempt to donate with a charitable contribution pledge for children in developing countries. The intervention involved 344 blood drives and 21,888 participants. Compared to a control condition with no pledges, the pro-social incentives significantly increased blood donation rates by approximately 5% on average. Offering a day or a week’s worth of food for vulnerable populations led to the largest and most robust increases in donations, and repeated exposure to incentives had a reinforcing effect on subsequent donation behavior, especially for individuals who previously donated when incentivized. An auxiliary survey examining the perceived importance and motivational impact of food-related incentives corroborates our findings. Our results suggest that coordination between blood donation campaigns and humanitarian aid programs could enhance the blood supply at minimal additional cost. More broadly, policymakers and nonprofit organizations can align global and local altruism by linking humanitarian assistance with initiatives promoting civic engagement and public health.