Skip to Main Content

Promotion and Tenure at UNO

What is the Impact Factor?

Created by Thomson Reuters, the Impact Factor is the most widely-recognized method for attempting to gauge a journal's rank/importance.  It is particularly well-known in the Sciences and Social Sciences.

Find the Impact Factor using InCites

  1. Go to Web of Science (link above) and click on the Journal Citation Reports (at the top) and search for your specific journal using the search box.

InCites Journal Reports screen shot step 1

  1. The Impact Factor should be highlighted at the top of the page.

InCites Journal Citation report screen shot step 2

  1. If you want Rank, Cited Journal data, and other information for multi-year comparisons, the source data can be found down further on the page.

InCites journal citation reports screen shot step 3

  1. This will open a new page so you can see the traditional table layout from previous years.

Incites journal citation reports screen shot step 4

Impact Factors: Use with care

Informed and careful use of these impact data is essential. Users may be tempted to jump to ill-formed conclusions based on impact factor statistics unless several caveats are considered.
When considering the use of the impact factor (IF), keep these aspects in mind:

  • IF analysis is limited to citations from the journals indexed by the Web of Science/Web of Knowledge.  Currently, the Web of Science indexes only 8621 journals across the full breadth of the sciences, and just 3121 in the social sciences.
  • A high IF/citation rate says nothing about the quality -- or even, validity -- of the references being cited.  Notorious or even retracted articles often attract a lot of attention, hence a high number of citations. The notority related to the first publication on "cold fusion" is one such example.
  • Journals that publish more "review articles" are often found near the top of the rankings.  While not known for publishing new, creative findings, these individual articles tend to be heavily cited.
  • The IF measures the average number of citations to articles in the journal -- given this, a small number of highly-cited articles will skew the figure.
  • It takes several years for new journals to be added to the list of titles indexed by the Web of Science/Web of Knowledge, so these newer titles will be under-represented.
  • It's alleged that journal editors have learned to "game" the system, encouraging authors to cite their works previously published in the same journal.

Impact factors have often been used in advancement and tenure decision-making.  Many recognize that this is a coarse tool for such important decisions, and that a multitude of factors should be taken into account in these deliberations.

Comparing journals across disciplines: Don't do it

Using Impact Factors within a given discipline should only be done with great care, as described above.  Using impact factor data to compare journals across disciplines is even more problematic.  Here are some of the reasons:

  • Disciplines where older literature is still referenced, such as Chemistry and Mathematics, offer challenges to the methodolgy since older citations (older than two years) are not used to calculate the impact factor for a given journal.  (Five-year impact factor analysis, which can be calculated using the Journal Citation Index database, helps smooth out this problem only to some degree.)
  • Different disciplines have different practices regarding tendency to cite larger numbers of references.  Higher overall citation rates will bump upward impact factor measurements.
  • Where it's common for large numbers of authors to collaborate on a single paper, such as in Physics, the tendency of authors to cite themselves (and in this case, more authors) will result in increased citation rates.

Resources discussing the Impact Factor