Do Celebrity Endorsements Matter? a Twitter Experiment Promoting Vaccination in Indonesia

Abstract

Do celebrity endorsements matter? And if so, how can celebrities communicate effectively? We conduct a nationwide Twitter experiment in Indonesia promoting vaccination. Celebrity messages are 72 percent more likely to be passed on or liked than similar messages without a celebrity’s imprimatur. In total, 66 percent of the celebrity effect comes from authorship, compared to passing on messages. Citing external medical sources decreases retweets by 27 percent. Phone surveys show that those randomly exposed to messaging have fewer incorrect beliefs and report more vaccination among friends and neighbours. The results can inform public health campaigns and celebrity public service more generally.