WISER: Bibliometrics II
The Black Art of Citation Rankings
Angela Carritt
Juliet Ralph
March 2011
These slides are available on
http://www.bodleian.ox.ac.uk/services/training
/wiser/presentations
Overview of Session
• What are bibliometrics?
• Why bother?
• Problems
• Calculating impact factors using Web of Science
•
•
•
…for an article
…for a researcher
…for a department / institution
• Calculating impact factors using Scopus
• Calculating journal impact factors using the Journal Citation
Reports
What are bibliometrics?
•…the statistical analysis of books, articles, or other
publications. Oxford English Dictionary
•…”ways of measuring patterns of authorship, publication
and the use of literature” HEFCE, Bibliometrics and the
Research Excellence Framework (REF)
• Use of citation information to measure the impact of
research
Citations to an individual paper
2010
2010
2010
2009
2008
2008
Citations to a researcher
Citations to a research
group/department
Citations to a journal
Continued….
• Wide range of formulae developed which aim to use
citation information to assess research impact accurately
• Some of the things that are sometimes considered…
•
•
•
•
•
•
Number of articles published
Number of self citations
Type of article
Period over which articles were published
Prestige of citing journal
Subject/discipline…
The power behind
Why bother?... REF
• “The pilot exercise showed that citation information is not sufficiently
robust to be used formulaically or as a primary indicator of quality; but
there is considerable scope for it to inform and enhance the process of
expert review” HEFCE www.hefce.ac.uk/research/ref/Biblio/
• Research Excellence Framework 2014
•
•
•
quality of research outputs (65% weighting 2014)
wider impact of research – (20% weighting in 2014) - measured by
case studies
vitality of the research environment 15% weighting in 2014)
• Expert panels decide whether or not to use citation information under
the “quality of research outputs” heading
• Panels to annouce their “criteria statements” in late 2011 - watch this
space
HEFCE, REF and citation information
• Central guidance to ensure that departments are not
disadvantaged by missing data
• Information will be standardized, simplified…and made
available to universities for a small fee
• HEFCE will assess the (financial) cost of using citation
information
• More @ http://www.hefce.ac.uk/research/ref/Biblio/
Why bother
• Benchmarking of departments and research groups
• Grant applications
• Recruitment of individuals
Lots of problems...
• Self-citations
• Negative citations
• Insignificant citations
• Multiple authors/research groups
• Incomplete citation lists - does not include citations in
books... or other publications not indexed by Web of
Science/Scopus…poor coverage of conferences
• Not comparable across disciplines – may disadvantage
researchers in interdisciplinary fields
• Review articles are more highly cited than original research
• More...
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Individual articles
• On Web of Science - use Cited Reference Search
• Better than General Search at retrieving Variants (incorrect
citations).
• Example:
• Effectiveness of PowerPoint presentations in lectures.
Author(s): Bartsch RA, Cobern KM
• Source: COMPUTERS & EDUCATION
• Volume: 41 Issue: 1 Pages: 77-86
• Published: AUG 2003.
Cited reference variant
Analyzing a highly cited article
Analyzing the Citing articles
…by highest citing Authors
…by highest citing Journals
or create a Citation Map
Citation map
Impact factors for a researcher
Citation report for an author
h-index=75
75 articles cited
75 times or more
Citation tracking & analysis in SCOPUS
• Scopus covers 18,000 journals in Science, Mecicine,
Social Sciences & Humanities
• Results include journal articles & conference proceedings
• Each record for a paper shows the number of times it has
been cited in Scopus since 1996
• Similar analytical tools to Web of Science
• www.scopus.com
Citation analysis in Scopus
h-index = 73
based on citations in
Scopus post-1996 to
537 papers
h-index = 63
if exclude
self-citations
…for a department or institution
• Not always easy!
• Web of Science - Search the Address field
• Must use standard abbreviations, e.g:
• oxford univ
• But word order makes a difference!
• univ oxford retrieves thousands more results
• more researchers use University of Oxford - not
Oxford University - in their address
• Can also search by postcode, e.g.
• OX1 2JD (Wellington Square)
Searching by Address
Check the abbreviations lists
Searching by department or college
•
•
•
•
•
Postcode or name
Tip: include univ oxford same or oxford same in
search string to weed out other institutions, e.g.
univ oxford same pathol
oxford same trinity
oxford same Ludwig Inst Canc Res
Scopus has Affiliation Search
•
•
Search by institution name not postcode
university of oxford retrieves same results as
oxford university
Scopus Affiliation Search
Scopus Affiliation ID
Symplectic Elements
Symplectic Elements
• record keeping tool for research outputs
• automatic searching of databases such as Web of Science
& Scopus
• Facility to run reports for a department
• For more information go to
• www.admin.ox.ac.uk/pras/research/symplectic/
• The solution for your department?
• Contact symplectic@admin.ox.ac.uk
Impact Factors - Journal Citation Reports (JCR)
• Compare relative importance of journals using citation
information
• Based on citation data from Web of Science
• Covers
• > 5,900 journals in science and technology
• > 1,700 journals in the social sciences
Uses & Abuses
• Uses
•
•
Help you to decide where to publish
Help librarians to make decisions about journal purchase etc
• Abuses
•
Have been used to measure research impact of individual and
research groups
Immediacy Index
Measures how quickly articles are cited.
Calculated:
no. of citations to articles published this year ÷ no. of
articles published this year.
Impact Factor - Number of times the
“average” article published in the previous 2
(or 5) years was cited this year.
Calculated:
no. of citations to articles published in the
last 2 (or 5) years ÷ no. of articles
published in same period.
Cited Half-Life - How many
years you have to go back to
account for 50% of citations
to the journal. e.g. 50% of
citations were to articles
published in the last 3.5
years. The rest cited earlier
articles.
Detailed view
Detailed view continued
Detailed view continued
Citations TO the journal by year of
cited article (e.g. 333 of this year’s
citations to Biological Review were
to articles published in in 2005 )
Detailed view continued
Citations from Biological
Review (to other journals
and self cites) by year of
cited article E.g. 334
citations from Biological
Reviews journal cited
articles published in 2007
Type of articles included
Eigenfactor Metrics
• Take into account prestige of
citing sources
• Use “Google style”
algorithms
• Attempts to measure how
often the average
researcher would encounter
the journal
• http://wellformed.eigenfactor.org/
Google’s PageRank from
http://en.wikipedia.org/wiki/PageRank
Eigenfactor: Score & Article Influence
• Eigenfactor – increases with the size of the journal
• Article Influence – Takes into account number of articles
published. More comparable to the JCR impact factor
Journal Impact Factors: Problems
Use with caution…Results are skewed by many factors…
• Size
• Frequency / time of publication
• Type of content - review articles are more heavily cited than original
research…
• Journals that are not indexed by WOS are disadvantaged
•
Non English Language journals disadvantaged
•
“Cited” only journals
• Problems when journals change names
• Results are not comparable across discipline (some journals in the
wrong discipline)
• Journal impact factors should NEVER be used to assess impact of
researchers / groups etc
Brief bibliography
General
• Broadus, R. N., “Towards a definition of Bibliometrics” Scientometrics,
vol. 12, nos 5-6, (1987) 373-379 @
www.springerlink.com/content/v111750n14086384/fulltext.pdf
• HEFCE papers, reports, papers and pilots on the use of bibliometrics
in the REF @ www.hefce.ac.uk/research/ref/Biblio/
H-Index
• Hirsch, J. E. (15 November 2005). "An index to quantify an individual's
scientific research output". PNAS 102 (46): 16569–16572 @
www.pnas.org/content/102/46/16569.abstract
• Ball, P. “Index aims for fair ranking of scientists”, Nature 2005 Aug 18
436: 900
Brief bibliography
Journal Impact Factors and the JCR
• The Thomson Reuters Impact Factor (originally published in the Current
Contents print editions June 20, 1994) @
http://thomsonreuters.com/products_services/science/free/essays/impact_factor/
• Garfield, E. "The agony and the ecstasy: the history and meaning of the
Journal Impact Factor“ Paper at the International Congress on Peer Review
And Biomedical Publication, Chicago, September 16, 2005 @
http://garfield.library.upenn.edu/papers/jifchicago2005.pdf
Want more…
• Wikipedia entries on the following topics include useful bibliographies: the
h-index, journal impact factors and the Eigenfactor
• A Google Scholar (http://scholar.google.co.uk/) search will return many useful
articles including subject studies on the use of bibliometrics