May 19, 2022

New Research Article: “Google Scholar, Web Of Science, and Scopus: A Systematic Comparison of Citations in 252 Subject Categories” (Preprint)

The following research article (preprint) was posted today on arXiv.


Google Scholar, Web Of Science, and Scopus: A Systematic Comparison of Citations in 252 Subject Categories


Alberto Martín-Martín
Universidad de Granada

Enrique Orduna-Malea
Universitat Politècnica de València

Mike Thelwall
University of Wolverhampton

Emilio Delgado López-Cózar
Universidad de Granada


via arXiv
August 15, 2018 (Version 1.1)


Despite citation counts from Google Scholar (GS), Web of Science (WoS), and Scopus being widely consulted by researchers and sometimes used in research evaluations, there is no recent or systematic evidence about the differences between them.

In response, this paper investigates 2,448,055 citations to 2,299 English-language highly-cited documents from 252 GS subject categories published in 2006, comparing GS, the WoS Core Collection, and Scopus.

GS consistently found the largest percentage of citations across all areas (93%-96%), far ahead of Scopus (35%-77%) and WoS (27%-73%). GS found nearly all the WoS (95%) and Scopus (92%) citations. Most citations found only by GS were from non-journal sources (48%-65%), including theses, books, conference papers, and unpublished materials. Many were non-English (19%-38%), and they tended to be much less cited than citing sources that were also in Scopus or WoS.

Despite the many unique GS citing sources, Spearman correlations between citation counts in GS and WoS or Scopus are high (0.78-0.99). They are lower in the Humanities, and lower between GS and WoS than between GS and Scopus. The results suggest that in all areas GS citation data is essentially a superset of WoS and Scopus, with substantial extra coverage.

Direct to Full Text Article (Preprint)
22 pages; PDF.

About Gary Price

Gary Price ( is a librarian, writer, consultant, and frequent conference speaker based in the Washington D.C. metro area. Before launching INFOdocket, Price and Shirl Kennedy were the founders and senior editors at ResourceShelf and DocuTicker for 10 years. From 2006-2009 he was Director of Online Information Services at, and is currently a contributing editor at Search Engine Land.