Short- and Long-Term Effects of Incentives on Prosocial Behavior: The Case of Ride Vouchers to a Blood Collection Agency

This study addresses the challenge of low blood donation rates in developing countries by examining the effectiveness of a barrier-removal incentive—a one-day transportation voucher—to promote blood donation. Utilizing a longitudinal dataset of 23,750 donors from a Brazilian blood collection agency (BCA) collected between March 2018 and May 2020, we examine the short and long-term effects of this campaign on donation rates. Our results show that the incentive had a large positive influence on both donation attempts and successful donations on the day of the campaign. However, the short-term success of the intervention had an unintended consequence: the significant increase in prospective donors' waiting time at the BCA during the intervention day, which may help explain the negative impact on return rates in the 24-month follow-up. Despite these opposing outcomes, the net effect of the one-day blood donation incentive was still positive, offering valuable insights for BCAs aiming to enhance donor recruitment and retention strategies and emphasizing the need to balance immediate benefits with potential long-term impacts.