Do original tweets and retweets differ in indicating research impact across various subject areas in multidisciplinary papers published in PLoS?

Earlier altmetrics studies have often focused on investigating whether the number of tweets mentioning scientific articles could be used as an indicator of scientific impact or attention, with results showing weak to moderate correlations with citation counts and some disciplinary differences. But all tweets may not be equal, as original tweets and retweets may reflect different levels of engagement and, with that, impact. In this research, the relationship between original tweets and retweets and Scopus citations was analyzed for a total of 330,022 PLoS publications and compared over time and across 22 subject fields. The findings showed that the correlations were strongest between citations and original tweets, and the relationship was stronger in Social Science and Humanities subject fields than in Natural Science, Engineering and Medicine. The results showed that tweets and retweets are very different, and thus they should be considered two different metrics and analyzed separately.