Transmissibility of the Ice Bucket Challenge among globally influential celebrities: retrospective cohort study

Ni, Michael Y; Chan, Brandford H Y; Leung, Gabriel M; Lau, Eric H Y; Pang, Herbert

We completed a marathon viewing of 145 Ice Bucket Challenges up to 13 September 2014. For each case we recorded the age, sex, occupation, net worth, popularity (proxied by number of likes on Facebook and number of Twitter followers), number of successful nominations, and total number of nominations. We obtained personal details of the celebrities from Wikipedia and specialised websites, although the validity of such information cannot be reliably ascertained.11 Wikipedia has been used in previous studies12 13 and its comparative accuracy has been reported.14 From verified accounts we obtained the number of Facebook likes and Twitter followers. Where these were not available, we used the unofficial accounts with the most likes or followers. We excluded unofficial accounts with fewer than 1000 likes or followers.