  Previous studies have developed different categorizations of Twitter users
who interact with scientific publications online, reflecting the difficulty in
creating a unified approach. Using Cochrane Review meta-analysis to analyse
earlier research (including 79,014 Twitter users, over twenty million tweets,
and over five million tweeted publications from 23 studies), we created a
consolidated robust categorization consisting of 11 user categories, at
different dimensions, covering most of any future needs for user
categorizations on Twitter and possibly also other social media platforms. Our
findings showed, with moderate certainty, covering all the earlier different
approaches employed, that the predominant group of Twitter was individual users
(66%), being responsible for the majority of tweets (55%) and tweeted
publications (50%), while organizations (22%, 27%, and 28%, respectively) and
science communicators (16%, 13%, and 30%) clearly contributed to a lesser
degree. These individual users consisted of both academic individuals (33%) and
other individuals (28%). While academic individuals shared more academic
publications than other individuals (42% vs. 31%), they posted fewer tweets
overall (22% vs. 30%), but these differences do not reach statistical
significance. Despite significant heterogeneity arising from variations in
earlier categorizations, the findings consistently indicate the importance of
academics in disseminating academic publications on Twitter.
