How Do I...
- Is a number used to indicate how influential, or important a particular journal is.
- Was developed in the late 1950’s by Eugene Garfield at the Institute of Scientific Information (ISI), now called Thompson Scientific (a large publisher).
- Impact Factor refers to a journal, not to an article, and not to an author (although publishing an article in a journal with a high impact factor is generally considered prestigious)
- The benefits and pitfalls of impact factors are a widely discussed topic in academia. Others measures exist to evaluate the influence of journals, articles, and authors.
How To Find a Journal’s Impact Factor:
- From the Library Databases Page select Journal Citation Reports (aka: JCR, and InCites Journal Citation Reports).
From Library Home Page --> Databases A-Z --> Enter “Journal Citation Reports”
- To find Impact Factor for a journal:
- Enter the name of the journal in the GO TO JOURNAL PROFILE box
- Impact factor is in the second column labeled “Journal Impact Factor.”
- Boxes on the left allow you to limit by: year, Select the year you want and either the Science or Social Sciences edition of JCR.
- Unless your assignment specifies otherwise, use the default options and choose the most recent year available
(this is usually at least 1 year ago, i.e., in 2012 the most recent impact factors available will be for 2011)
How Impact Factors Are Calculated:
2005 Impact Factor for Journal X = A / B, where:
A = Number of times articles published in Journal X in 2003-2004 were cited by indexed journals in 2005
B = Number of articles published in Journal X in 2003-2004
Things to be aware of:
- "indexed journals" means journals indexed by Thompson Scientific (makers of the Web of Science database). If Thompson Scientific doesn't index the journal, it doesn't get included.
- "number of articles" Thompson Scientific also decides what counts as an "article" (or "citable item"). Usually included are: articles, communications, reviews, notes, etc. Excluded are "news" type items, letters to the editor, etc.
- The lower the denominator, the higher the impact factor.
- A journal's impact factor refers to a certain year: impact factors do vary from year to year, although most established journals tend to have fairly consistent impact factors (i.e., they don't vary widely).
For more information, see: Using JCR Wisely