journal citation reports ® “the jcr” jon stroll, key account manager...
TRANSCRIPT
Agenda:
The Data
The JCR
The Enhancements
Use and Misuse
A BRIEF HISTORY OF THE CITATION INDEX
• Concept first developed by Dr Eugene Garfield – Science, 1955
• The Science Citation Index (1963)– SCI print (1960’s)– On-line with SciSearch in the 1970’s – CD-ROM in the 1980’s– Web interface (1997) Web of Science
• Content enhanced:– Social Sciences Citation Index (SSCI)– Arts & Humanities Citation Index (AHCI)
• The Citation Index – Primarily developed for purposes of information retrieval– Development of electronic media and powerful searching tools
have increased its use and popularity for purposes of Research Evaluation
THE VALUE OF A CITATION
• Why do people cite?– Pay homage / give credit to pioneer
– Identifying a methodology
– Provide background reading
– Quotations
– Authenticating data, reproducing work etc
– Corrections
– Criticizing/Disclaiming someone's work/opinions
• Citations are an indicator of an article’s impact and usefulness to the research community; they are the mode by which peers acknowledge each other’s research.
• The value of a citation is only as important as its source. – Clearly a citation from a prestigious peer review journal has more value than a
citation from non-scholarly material.
– How can you be sure that the citing source is reputable?
“When to Cite”, E. Garfield, Library Quarterly, v66, p449-458, 1996
WHY NOT INDEX ALL JOURNALS?
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20
40
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120
0 1000 2000 3000 4000 5000 6000
# of journals
% o
f dat
abas
e
Articles Citations
40% of the journals:
• 80% of the publications
• 92% of cited papers
4% of the journals:
• 30% of the publications
• 51% of cited papers
HOW DO WE DECIDE WHICH JOURNALS TO INDEX?
• Approx. 2.500 journals evaluated annually
– 10-12% accepted
• Thomson Reuters editors– Information professionals
– Librarians
– Experts in the literature of their subject area
Web of Science
Journals under evaluation
Journal ‘quality’
THOMSON REUTERSJOURNAL SELECTION POLICY
• Publishing Standards– Peer review, Editorial conventions
• Editorial content– Addition to knowledge in specific subject field
• Diversity– International, regional influence of authors, editors, advisors
• Citation analysis– Editors and authors’ prior work
Region # Journals from Region in Web of Science
Europe 5,573 49%
North America 4,251 38%
Asia-Pacific 965 9%
Latin America 272 2%
Middle East/Africa 200 1%
Language # Journals in Web of Science
English 9114 81%
Other 2147 19%
GLOBAL RESEARCH REPRESENTATIONWEB OF SCIENCE COVERAGE
Agenda:
The JCR
A DEFINITION:JOURNAL IMPACT FACTOR
2009 Impact Factor
200920082007
Source paper – published in 2009
Cited reference – published in 2007 or 2008
Citations
All Previous Years
2006 2010
CALCULATING 2009 JOURNAL IMPACT FACTOR HEALTH ECONOMICS
Citations in 2009To items published in 2008 = 156
To items published in 2007 = 210
Sum = 366
Number of itemsPublished in 2008 = 97
Published in 2007 = 85
Sum = 182
366
182
= 2.011
Agenda:
The Enhancements
Why add additional metrics to the JCR?
Our objective in including this new information is to expand one’s evaluative
perspective on scholarly journals, to provide a more thorough and well-rounded overview
of their overall impact and influence.
Journal Citation Reports ® – Enhancements
New Metrics & Information
• Five-Year Impact Factor
•Rank-in-Category Tables
•Box Plots
•Illumination of Journal Self-Citations
•Eigenfactor MetricsTM: EigenfactorTM and Article InfluenceTM
Journal Citation Reports ® – Enhancements
Citation Behavior, variance among disciplines:Some fields are very fast moving, particularly within the life sciences, and published research gets cited at a relatively rapid pace. Research in other fields, mathematics for example, makes its impact more slowly over an extended period of time.
Differences in citation curves at the category level
0%
2%
4%
6%
8%
10%
12%
2006 2005 2004 2003 2002 2001 2000 1999 1998 1997Cited year
% o
f to
tal c
itat
ion
s to
th
e ca
teg
ory
Cell Biol (5.9)
Med, Gen Int (7.1)
Math (>10)
Multidisc (7.6)
Econ (>10)
Education(8.3)
2006 Impact Factor Years
Journal Citation Reports ® – Enhancements
Immunology
Journal Citation Reports ® – EnhancementsIntroduction of a 5-Year Impact Factor:To better gauge the impact of journals within fields where influence of published research evolves over a longer period of time than presented by the traditional 2-Year Impact Factor.
Impact Factor is based on two years of cited journal content – cites in the current year to journal material published in the prior two years.
A 5-Year Impact Factor is based on cites in the current year to journal material published in the prior five years.
Journal Citation Reports ® – Enhancements
Geology
Introduction of a 5-Year Impact Factor:To better gauge the impact of journals within fields where influence of published research evolves over a longer period of time than presented by the traditional 2-Year Impact Factor.
Geology
Impact Factor is based on two years of cited journal content – cites in the current year to journal material published in the prior two years.
A 5-Year Impact Factor is based on cites in the current year to journal material published in the prior five years.
Journal Citation Reports ® – Enhancements
Rank in Category table:Many journals maintain an editorial scope that necessitates their inclusion in more than one JCR category. To better reveal the influence of a journal in all assigned categories a Rank in Category table will display each category in which the journal appears along with rank in the category and the Quartile in which the journal is placed in that category - based on Impact Factor.
Journal Citation Reports ® – Enhancements
Category Box Plot:A category Box Plot accompanies the Rank in Category table. The spacing between the different parts of the box, the quartiles, helps indicate the degree of dispersion of impact of journals within the category. View the journal's Impact Factor in the context of all Impact Factors for the journal's category as depicted by the graph – envisioning a line at the position of the journal’s Impact Factor helps one to better comprehend the display.
Journal Citation Reports ® – Enhancements
Journal Self-Citation itself is not an inherently “bad” practice.
Authors of course cite related research and this may have been published in the journal to which one in turn submits a paper for publication.
Journals with a very specialized subject focus may naturally display significant rates of self-citation.
However -- 80% of all journals listed in the JCR Science Edition have self-citation rates of less than 20%. Based on trends within a category we can get an idea of what may be excessive self-citation, which weakens the integrity of the journal’s Impact Factor.
Journal Self-Citation
Journal Citation Reports ® – Enhancements
Illumination of Journal Self-citation Rates:To provide one the ability to easily compare self-citation rates among journals particularly as this influences Impact factor calculations.
Category: Materials Science, Composites
Journal Citation Reports ® – Enhancements
Eigenfactor MetricsTM: EigenfactorTM and Article InfluenceTM:
To compliment Impact Factor and other JCR metrics by providing a broader perspective on Journal Influence through specific measures now widely accepted by the scholarly community.
These metrics are developed through The Eigenfactor Project™ -- a non-commercial academic research project sponsored by the Bergstrom lab in the Department of Biology at the University of Washington. – www.eigenfactor.org
Journal Citation Reports ® – Enhancements
EigenfactorTM Score:
• Scholarly references join journals together in a vast network of citations. The Eigenfactor Score algorithm uses the structure of the entire network to evaluate the importance of each journal, cutting across all disciplines. Self-citations are excluded.
• This corresponds to a simple model of research in which readers follow chains of citations as they move from journal to journal.
• Eigenfactor calculations take into consideration a 5-year span of citation activity utilizing data from the Journal Citation Reports.
• Journals are considered to be influential if they are cited often by other influential journals.
Journal Citation Reports ® – Enhancements
Article InfluenceTM Score:
• As with Eigenfactor Score, Article Influence Score:– Uses the structure of the entire citation network to evaluate the importance of
each journal, based on JCR data.
– Does not consider self-citations
• The calculation of Article Influence Score does in fact incorporate Eigenfactor Score.
• However, as Eigenfactor Score can be described as presenting the total collective value provided by all of the articles published in a journal in a year – Article Influence Score measures the average influence of individual articles appearing in the same journal, translating to the importance of an article published in that journal.
• Because it does present an average for article-level influence, Article Influence is more like the Impact Factor than Eigenfactor Score – though keep in mind the methodology is quite different and therefore provides a perspective different from but complimentary to Impact Factor.
Agenda:
Use and Misuse
USING THE IMPACT FACTOREVALUATING JOURNALS
• Appropriate use– To evaluate journals
• Misuse– Evaluation of individual articles
– Evaluation of institution or researcher
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USING THE IMPACT FACTOR MISUSE: EVALUATING INDIVIDUAL PAPERS
30% of articles in Food Policy were not cited at all
Source: Thomson Reuters Journal Citation Reports
Journal Impact Factor = 2,011
Any questions?