The second period of data collection was 30 days after each tweet. Social media attention metrics are highest soon after publication, and then dwindle rapidly [13, 32, 33]. At 30 days, the coordinator collected the Altmetric attention score and number of tweeters for all five papers, and asked the tweeter to obtain Twitter analytics for their tweet to get the number of tweet impressions and link clicks to the paper in the experimental arm (Table 1).