A longitudinal study of Google Scholar coverage between 2012 and 2013

• Published in: Scientometrics Vol. 98; no. 1; pp. 565 - 575
• Main Author: Harzing, Anne-Wil
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.01.2014; Springer
• Subjects: Bibliometrics. Scientometrics; Bibliometrics. Scientometrics. Evaluation; Citation indexes; Computer Science; Coverage; Exact sciences and technology; Information and communication sciences; Information science. Documentation; Information Storage and Retrieval; Library and information science. General aspects; Library Science; Sciences and techniques of general use; Search engines; Subject fields; Trends; g-Index; Web of science; Social sciences; Citations; Google scholar; h-Index; Bibliometric analysis; Hirsch index; Scientometrics; Bibliometrics; Follow up study; Scientific research; Citation
• ISSN: 0138-9130; 1588-2861
• DOI: 10.1007/s11192-013-0975-y

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 respond in this research note. We use a sample of 20 Nobelists in Chemistry, Economics, Medicine and Physics and track their h-index, g-index and total citations in Google Scholar on a monthly basis. Our data suggest that—after a period of significant expansion for Chemistry and Physics—Google Scholar coverage is now increasing at a stable rate. Google Scholar also appears to provide comprehensive coverage for the four disciplines we studied. The increased stability and coverage might make Google Scholar much more suitable for research evaluation and bibliometric research purposes than it has been in the past.