Introduction to bibliometrics

1. Bibliometrics – a brief
introduction
Anne Costigan
Library
LSS

2. Measuring impact through
publications
• Uses citations
– Article is given as reference by another author –
‘cited’
– Web of Knowledge
– Google Scholar
– Scopus
– Journal websites

3. Citations to an article
• Combined to produce metrics for
– Journal
– Author
– Research group
– Institution
– Country

4. Why should I be interested in
bibliometrics?
• Journal level – suggest journals in which to
publish
• Article/author level – measure your own
progress
• Research group/institutional – where should I
apply for a job?

5. Others use bibliometrics too…
• Journals – Librarians looking at subscriptions
• Article/author – managers and recruiters
• Research group/institution – managers and
research funders

6. Impact Factors – an introduction
• The most widely-used Impact Factors available
only from Journal Citation Reports, part of
Web of Science
• Only a journal has an Impact Factor, not an
author or an article
• A measure of the frequency with which an
average article in a journal has been cited in a
particular year

7. Impact Factors – a definition
• Impact Factor of a journal for 2012
– Number of citations in 2012 to articles published in
previous two years
• Divided by
– Total number of articles published in previous two years
• Impact Factor for IEEE Spectrum
– Number of citations in 2012 to articles published in 2010
and 2011 = 152
– Total number of articles published in 2010 and 2011 = 115
– Impact Factor = 152/115 = 1.322

8. IEEE Spectrum rank and trend

9. What is a ‘good’ Impact Factor in
science?
• Highest Impact Factor for 2012 is 153.459 (CA – A Cancer
Journal for Clinicians)
• Median Impact Factor for 2012 is 1.352 (International Journal
for Numerical Methods in Fluids)
• Lowest Impact Factor for 2012 is 0 (9 journals tied)
• Can vary quite considerably

10. What is a ‘good’ Impact Factor in
social science?
• Highest Impact Factor for 2012 is 18.571
(Behavioral and Brain Sciences)
• Median Impact Factor for 2012 is 0.845
(Journal of Contemporary Asia)
• Lowest Impact Factor in 2012 is 0 (Shared by
12 journals)

11. Elsevier and Scopus
• Scopus
– Elsevier’s journal article search engine
– Includes citation counts for individual items
• SCImago JR
– http://www.scimagojr.com/index.php
– Use Scopus data to calculate ‘impact data’ for journals

12. Google Scholar journal rankings
• http://scholar.google.co.uk/citations?
view_op=top_venues
• Google Scholar citations occasionally
unreliable!

13. Are there any other types of journal
metrics?
• Ranking systems
– Management – widely used
• http://www.lib.uwo.ca/business/Rank.html
• http://www.harzing.com/resources.htm
– European Reference Index for the Humanities –
NOT widely used
• http://www.esf.org/index.php?id=4813

14. New developments in
bibliometrics
• Citations at level of:
– Author
– Article
– Research group
– Institution
• http://www.leidenranking.com/ranking
• InCites (for purchase)
• SciVal (for purchase)

16. Other citation systems
• Scopus – not held by the Library
– But can get citations anyway!
• Citations in Google Scholar
• Citations in and between e-journal services

17. Citations in Google Scholar
• Interesting but not always reliable!
• Publish or Perish
– Generates citation figures from GS at author or
journal level
– Free download from
• http://www.harzing.com/pop.htm

18. Profiles in Google Scholar

19. H-index (Hirsch index)
• Originally author-based:
– An author has index h if h of their papers has been
cited at least h times
– Eg if you have published 20 papers which have
been cited 20 times your h-index is 20
– Authors who don’t do well in the h-index:
• Those who write large numbers of low-citation papers
• Those who have only one highly-cited paper
• Younger authors

20. How do I find an author’s H-index?
• Web of Knowledge
– Web of Science only
– Create Citation Report
• Also available via Scopus (automatic) and
Google Scholar (your own calculations)
• NB All the databases are different so different
H-indexes will be calculated

21. Other measures
• H-index expanded
– Can cover
• groups of authors (eg a university department)
• groups of documents (eg a journal)
– SCImago provides H-Indices for journals
– Scopus can also provide them!
• G-index and others

22. Why do bibliometrics vary by
discipline?
• In subject areas with low numbers of citations,
citations are missed
– Smaller number of journals indexed
– Many papers published in non-journal sources
– Just not as many publications out there!
• In sciences
– Largely journal-based literature
– Well covered by ISI

23. What’s in Web of Science?
• Journals
– Mostly peer-reviewed (not all)
• Life Sciences bias in Science JCR – 50%
• US bias
• English language bias

24. What isn’t in Web of Science
• Non-journal literature
• New journals
– Need at least two years for calculation of Impact
Factors
– Need to build reputation
• Journals that change titles!

25. Academic validity of bibliometrics
• Controversial
• Biases in journal selection
• Self-citations – 13%
• Review journals ‘over-rated’
• Common author names a problem – use ORCID etc
• Free/’open access’ journals highly-rated?
• Probably better in Life Sciences than in other fields
• Journals - look at position in ranking rather than absolute
numbers
• Journals - look at trends

26. IEEE Spectrum rank and trend

27. Criticisms of bibliometrics
• Blockbuster paper
• Incorrect papers (Hwang example)
• Errors – often due to poor referencing

28. What else can we measure?
• Altmetrics
– Article usage
• How many times is an article accessed?
– Social media
• How many times is an article mentioned on Twitter or
Facebook?

31. Useful guide
• Measuring Research Impact
– http://library.soton.ac.uk/bibliometrics