Promoting blood donation through social media: Evidence from Brazil, India and the USA.

Social media has the potential to encourage prosocial behaviors at scale, yet very little causal evidence exists on the impact of related efforts. Blood donation is a particularly difficult, but essential prosocial behavior that is often critically undersupplied. We examine the effect of Facebook's blood donation tool on voluntary blood donation. We partnered with four major blood banks in the United States covering 363 collection facilities in 46 states and Washington, D.C. We tracked the tool's impact on blood donations during its staggered rollout on a sample of more than 47,000 facility-date observations from March 2019 to September 2019. The tool caused an increase of 0.55 total donations per facility per day (+4.0% [95% CI: 0.04%-8.0%]), and an increase of 0.15 donations from first-time donors per facility per day (+18.9% [95% CI: 4.7%-33.1%]). Longitudinal evidence from Brazil and India suggests the share of donors who both received a message from the tool and stated they were influenced by Facebook to donate increased from 0% to 14.1% [95% CI: 12.1%-16.2%] in the first year of the tool's deployment (i.e., September 2018 to August 2019). These meaningful increases, especially from first-time donors, demonstrate that social media platforms can play an important role in fostering offline prosocial behaviors that benefit the health and well-being of societies around the world.