Calculating the h-index:
Web of Science, Scopus or Google Scholar?
•The h-index , a method of measuring the productivity and impact of an academic’s work, is often used as a component or
metric in the ranking of higher education institutions and their staff
•The principle citation databases used in this exercise are: Web of Science (WoS), Scopus and Google Scholar (GS) and the pros
and cons of using each of the three databases to calculate the h-index are discussed below
•The h-index defined: a researcher has an h-index of 25 if 25 of their papers have been cited at least 25 times
•These databases are selective in their journal coverage and some disciplines are better served than others. Also, conference
proceedings and monographs, which are key research communication channels in some subjects, are not adequately covered.
These factors should be kept in mind when assessing the h-indices of researchers in such disciplines
Web of Science
Google Scholar
Scopus
Pros
Pros
•Includes more than 18,000 journal titles
•Covers not only journals but academic
•Covers some books and conference
websites, grey literature, pre-prints, theses etc
proceedings
•Also includes books from the Google Books project
•The
‘more’ feature allows you to quickly view
• Includes electronic-only publications
stray and orphan records
• Adds a record to the database for every cited work
•Very
strong coverage of science and
found so that these are directly visible in the results list
technology
journals and full Medline coverage
which is not limited to the originally choice of indexed
•Contains
useful
tools for author disambiguation
titles and sites
•Automatically generates the h-index
WoS citation analysis for Stephen Hawking
Cons
Cons
Pros
• Does not automatically calculate the h-index (but you
can use “Publish or Perish” software to do this or try the• Depth of coverage is not as impressive as the width,
many journals are only covered for the last 5 years
Scholarometer add-on for Firefox)
• Excellent depth of coverage in the full product
• Relatively poor coverage of arts and humanities
• Does not provide a list of journals and other items
(from 1900-present for some journals)
(recently improved somewhat as more journals added)
indexed and covered (peer reviewed or otherwise)
• A large number of the records are
•The
citations and calculations based on them are only
• Does not indicate the timescale covered
enhanced with cited references
• Covers some non-scholarly or research level sources available from publications since 1996. This results in a
• Regional journal coverage has been improved
very skewed h-index for researchers with longer
e.g. course reading lists, student projects
• The first database to incorporate the h-index
careers
than this.
• Poorer coverage of print-only material than rivals
(using a good graphical display)
• Difficult to distinguish between authors who have the •Citations to pre-1996 articles in articles published after
•You can view the h-index minus self citations,
1996 are not included in the h-index calculation.
though this only removes them for the first author same initials in this product, so a lot of manual check and
• Conference proceedings coverage has improved pruning of result sets is needed
• Results often contain duplicates of the same article
• You can view stray and orphan records using
the “cited references” search feature to expand the (usually as pre-prints and post-prints) due to the wide
range of sources
citation set
Cons
• Coverage of journal titles is not as wide as Scopus
(around 10,000 active journals)
• Better coverage of sciences than arts
and humanities
• Does not cover monographs in any depth
• Facilities for finding and distinguishing between
authors are not great in the product
• Western, US and English language bias
Example:
H-index values* for
Stephen Hawking:
WoS
59
Scopus
19
GS
76
Generated in each database using
the automatic h-index tool provided
(for GS, Publish or Perish software
used). No manual verification conducted.
Scopus h-index graph for Stephen Hawking
References
Bakkalbasi, N., Bauer, K., Glover, J. and Wang, L. 2006. Three options for citation tracking: Google Scholar, Scopus and Web of Science. Biomedical Digital Libraries,3
Bar-Ilan, J., 2008. Which h-index? - a comparison of Web of Science, Scopus and Google Scholar. Scientometrics, 74, 257-271.
Hirsch, J. E. ,2005. An Index to Quantify an Individual's Scientific Research Output. Proceedings of the National Academy of Sciences of the United States of America, 102, 16569-16572.
Jacso, P., 2008.The Pros and Cons of Computing the h-Index Using Scopus. Online Information Review, 32, 524-535.
Jacso P., 2008. The Pros and Cons of Computing the h-Index Using Web of Science. Online Information Review, 32, 673-688.
Jacso, P.,2008 Testing the Calculation of a Realistic h-Index in Google Scholar, Scopus, and Web of Science for F. W. Lancaster. Library Trends, 56, 784-815.
Jacso, P. T., 2008.The pros and cons of computing the h-index using Google scholar. Online Information Review, 32, 437-452.
Meho, L. I. and Yang, K., 2007. Impact of data sources on citation counts and rankings of LIS faculty: Web of Science versus Scopus and Google Scholar. Journal of the American Society
for Information Science and Technology, 58, 2105-2125
Website: http://www.ndlr.ie/myri/
Last edited: 17 Apr 2011