Tuesday, November 25, 2008

Recurring Reference Questions: What is a Journal's Impact Factor, and How Can I Find It?




An Impact Factor (IF) provides a quantitative assessment of a journal's influence or impact. Thomson Scientific (now Thomson Reuters Scientific) offers the Impact Factor via Journal Citation Reports (JCR). According to Thomson Reuters, the Journal Impact Factor is the frequency with which the “average article” in a journal has been cited in a particular year. A journal’s Impact Factor is determined by dividing the number of citations in the JCR year by the total number of articles published in the two previous years. A Journal Impact Factor of 4.0 means that, on average, the articles published in that journal within the past three years have been cited four times. There must be at least two years of data in order to calculate the Impact Factor.

Using Impact Factors (IF) Wisely:


As Thomson Reuters indicates on their Information About page, one should not depend entirely on JCR data to evaluate a journal because:


  • IF only includes journals indexed by Thomson Reuters Scientific (ISI).


  • IF does not evaluate individual researchers.


  • Journals can only be compared within the same discipline. Citation results vary widely across disciplines.


  • The number of articles found in journals include both research and review articles. "Citation counts in JCR do not distinguish between citations to letters, reviews, or original research articles, even though only original research and review articles are used in IF calculations."


  • Title changes or changes in format of a journal affects the IF.


  • Some Additional Methods for Constructing Impact Factors:


    Google Scholar - From the Advanced Search screen, enter author and title information to obtain cited references. Publish or Perish may be used to track an author's impact using Google Scholar.

    eigenfactor.org - Ranking and Mapping Scientific Journals

    Journal Ranking - Center for Journal Ranking (CJR)



    To Find Journal Citation Reports:

    Go to the Mildred F. Sawyer's home page, and select "Databases by Subject." Choose "Business and Management" or "Social Sciences" and click on Journal Citation Reports in the list.


    To Utilyze JCR:


  • From the opening screen, select an option.


  • View journals by Subject, Publisher, Country/Territory. The default option is subject categorySearch for a specific journal.


  • Search for a specific title.


  • View all journals in the JCR edition and year you selected. (The Sawyer Library has the Social Sciences edition from 1998 forward).


    For example, if searching by Subject Category, select the subject from the second screen, and choose data sorted by journal title, total cites, impact factor, or other options provided from the drop-down menu. Use the Information for New Users button for more detailed information and instructions.




    [FIND Journal Citation Reports in our "Databases by Subject" Lists for Business and Management and for Social Sciences]




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