Journal Impact Factors and H index Journal Impact Factors and H index

Arife Ahsen KaplanMSc Student

Histology and EmbryologyMedical School

Ondokuz Mayıs UniversitySamsun, Turkey

ContentsContentsoJournal Impact Factors:

• Why?

• Where?

• What? o Other Journal Ranking Factors

oH index

*http://www.scienceclub.listbb.ru/knowledge/kb_show.php?id=48**http://portal3.ipb.pt/index.php/en/bibliotecas/the-documentation-services-and-libraries

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Journal Impact Factors: Journal Impact Factors:

Why? Why? Where? What? Where? What?

Why?o Evaluate the scholarly worth of a journalo Rank journals within a disciplineo Help you decide where to publish your article for

maximum impacto Evaluation for promotion / tenure / grants, or in some

countries, even government funding of an institution

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Journal Impact Factors: Journal Impact Factors:

Why? Why? Where?Where? What? What?

Where do we find Impact Factors?

Impact factors are listed in Journal Citation Reports JCR)

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Journal Impact Factors: Journal Impact Factors:

Why? Why? Where?Where? What? What?

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Journal Impact Factors: Journal Impact Factors:

Why? Why? Where?Where? What? What?

Web of Science®Web of Science®

Thomson Reuters (formerly ISI) has one, huge database, Web of Science, that…o Indexes selected journals

> 8,000 science; > 3,000 social science journals; > 1,800 Arts & Humanities

o Activity: Search for an article in your field that has been highly cited.

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o What is the Journal Impact Factor? o How is it calculated?

E.g., Calculating the 2009 Journal Impact factor for the journal Cell =

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

*Only references in articles within the ~13,000 journals indexed in Web of Science are counted; does not include citations that may cite the articles in Cell from book chapters, proceedings, or other journals that are not indexed in Web of Science

* * Citable articles are just research articles and reviews – not news articles, commentary, etc. 8

Journal Impact Factors: Journal Impact Factors:

Why? Where? Why? Where? What? What?

That is:Cites in 2009 to items published in 2008 + 2007 = 9533 + 12554 =

22087     

Number of items published in Cell in 2008 + 2007 = 343 + 366 = 709 

Impact Factor        

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Journal Impact Factors: Journal Impact Factors:

Why? Where? Why? Where? What? What?

Criticisms of Journal Impact Factors…Criticisms of Journal Impact Factors…

o Only a limited subset of journals is indexed by ISIo Only uses the articles cited by the ~13,000 “ISI journals” o Some disciplines are especially poorly covered

o Biased toward English-language journalso ISI has recently added several hundred non-English journals

o Short (two year) snapshot of journal o Some disciplines use older material more or take time to cite new

researcho JCR now also includes the 5-year data

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o Includes self-citations, that is articles in which the article cites other papers in the same journal

o Only includes “citable” articles in the denominator of the equation, i.e., articles and reviews o Editors may skew IF by increasing the number of review articles,

which bring in more citations (increases the numerator)o Or by increasing the number of “news” items (e.g., Science, general

medical journals) , which are cited (appear in numerator) but not considered “citable” (and so aren’t in the denominator)

o It is expensive to subscribe to the JCR

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Criticisms of Journal Impact Factors…Criticisms of Journal Impact Factors…

Other Journal Ranking Efforts…Other Journal Ranking Efforts…

o Available free at eigenfactor.org (1995-2009 data)o As with the JCR, only ISI journals are rankedo Uses “all” ISI data, analyzed differently.

o all cited and citing references (so includes citations from non-ISI journals, books, dissertations, etc.)

o Looks at five years of data

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Eigenfactor.orgEigenfactor.org

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Eigenfactor.orgEigenfactor.org

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Biochemistry & Molecular Biology CategoryBiochemistry & Molecular Biology Category

o Eigenfactor Score: … the higher the bettero For a journal, the number of times articles published in the previous five years have been

cited in the current year.o Highly cited journals will influence the score more than lesser cited journals.o A measure of the journal’s total importance to the scientific community. o Eigenfactor scores are scaled so that the sum of the Eigenfactor scores of all journals

listed in Thomson’s Journal Citation Reports (JCR) is 100.

o Article Influence Score: … the higher the bettero The average influence, per article, of the papers in a journal. As such, it is comparable to

the Journal Impact Factor. o Article Influence scores are normalized so that the mean article in the entire Thomson

Journal Citation Reports (JCR) database has an article influence of 1.00. A score greater than 1.00 indicates that each article in the journal has above-average influence.

o Still, as with IFs, it’s best to “compare” within subjects.

o Cost Effectiveness: … the lower the bettero Annual Price / Eigenfactor Score

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Eigenfactor.orgEigenfactor.org

Comparing JCR and EigenfactorComparing JCR and Eigenfactor

For JCR Category “Cell Biology” (2008) -- the top six journals sorted by Journal Impact Factor

*In parenthesis, values normalized. 17

SCImago Journal Rank (SJR)SCImago Journal Rank (SJR)

o The citation PageRank of a journal calculated on the basis of the Scopus citation data divided by the number of articles published by the journal over 3 years.

o Similar to Eigenfactor methods, but based on citations in Scopus instead of Web of Science.

o Freely available at scimagojr.como Covers more journals (~20,000) than JCR because Scopus covers more

journals than Web of Scienceo More international diversityo 3 years of citations; no self-citations

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SCImago Journal Rank (SJR)SCImago Journal Rank (SJR)

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SCImago Journal Rank (SJR)SCImago Journal Rank (SJR)

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SCImago Journal Search SCImago Journal Search

•SJR from SCImago are based on the Scopus database, not the Web of Science database; both JCR and Eigenfactors are calculated from the Web of Science database. 22

Comparison of Three Journal Ranking Systems Comparison of Three Journal Ranking Systems

… Higher is … Higher is ““betterbetter”” in all cases (2007) in all cases (2007)

H indexH index

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oMeasure both the productivity and citation impact of the published body of work of a scientist or scholar.oBased on the set of the scientist's most cited papers and the number of citations that they have received in other publications.oThe index was suggested in 2005 by Jorge E. Hirsch to quantify an individual's scientific research output. oSometimes called the Hirsch index or Hirsch number.

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H indexH index

o Combines an assessment of both quantity (number of papers) and quality (impact, or citations to these papers).

o h-index is automatically calculated:o Web of Scienceo Scopus

*http://www.rsc.org/chemistryworld/2012/11/h-index-rankings-stop-chemist-chemistry

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H indexH index

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*http://en.wikipedia.org/wiki/H-index

Determining h-index ManuallyDetermining h-index Manually

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Web of Science

Finding a h-index value Finding a h-index value

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Finding a h-index value Finding a h-index value

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Scopus

Finding a h-index value Finding a h-index value

Citation Overview (h-index) from ScopusCitation Overview (h-index) from Scopus

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Graph of h-index from ScopusGraph of h-index from Scopus

Comparison of h-index Values Comparison of h-index Values

from Several Sources for Several Authorsfrom Several Sources for Several Authors

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Comparison of 2007 h-index Values Comparison of 2007 h-index Values

for Several Journalsfor Several Journals

* “Of the 2375 documents published in Science in 2007, 68 have been cited at least 68 times”** Value for h-index was calculated from citations from 1999-current, not just 2007.

x

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Criticisms of h-index…Criticisms of h-index…

o is bounded by the total number of publications: o hÉvariste Galois= 2, hAlbert Einstein=5

o does not consider the context of citationso citations are often made simply to flesh-out an introductiono citations made in a negative contexto citations made to fraudulent or retracted work

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Criticisms of h-index…Criticisms of h-index…

o is affected by limitations in citation databaseso does not account for the age of the articles and the age of

citationso does not account for the number of authors of a paper

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ConclusionConclusion

o Journal Impact Factors will likely be around for a long time… the key is to understand how they work.

o Don’t use Journal Impact Factors to evaluate individuals. Perhaps use h-index, instead?

o Use multiple resources (Web of Science, Scopus, etc.) to find how many papers have cited your works.

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THANK YOU…

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