A longitudinal study of Google Scholar coverage between 2012 and 2013

Harzing (Scientometrics, 2013) showed that between April 2011 and January 2012, Google Scholar has very significantly expanded its coverage in Chemistry and Physics, with a more modest expansion for Medicine and a natural increase in citations only for Economics. However, we do not yet know whether this expansion of coverage was temporary or permanent, nor whether a further expansion of coverage has occurred. It is these questions we set out to...