  Microsoft Academic is a free citation index that allows large scale data
collection. This combination makes it useful for scientometric research.
Previous studies have found that its citation counts tend to be slightly larger
than those of Scopus but smaller than Google Scholar, with disciplinary
variations. This study reports the largest and most systematic analysis so far,
of 172,752 articles in 29 large journals chosen from different specialisms.
From Scopus citation counts, Microsoft Academic citation counts and Mendeley
reader counts for articles published 2007-2017, Microsoft Academic found a
slightly more (6%) citations than Scopus overall and especially for the current
year (51%). It found fewer citations than Mendeley readers overall (59%), and
only 7% as many for the current year. Differences between journals were
probably due to field preprint sharing cultures or journal policies rather than
broad disciplinary differences.
