An Impact factor is a way of measuring the relative ranking of a journal within a particular field, and are included in the Journal Citation Reports developed by Thomson Scientific Research. It is a measure of the frequency with which the "average article" in a journal has been cited in a particular year or period.

The annual JCR impact factor is a ratio between citations and recent citable items published. Thus, the impact factor of a journal is calculated by dividing the number of current year citations to the source items published in that journal during the previous two years. For more information, see the Thomson Scientific Impact Factor.

To find the impact factor of a journal:

  • Select Journal Citation Reports
  • Select either JCR Science Edition or JCR Social Science Edition
  • Under Select an Option choose Search for a specific journal. Click on Submit
  • Type in the name of the journal name and click on Search
  • If the journal is listed in the Journal Citation Reports you should now see a Journal Summary List. This should include such information as the impact factor, the total number of citations and the number of articles for the previous year
  • Select the Abbreviated Journal Title for more information
  • Click the Impact Factor Trend to see the impact factor graph and figures for the last five years.

To compare this title with other titles in the field:

  • Click on the Return to Journal button 
  • Select the View journal summary list (under Journal Information). This will bring up a list of all titles in the same subject area
  • The list of results should be sorted by Journal title.  Change the sort option to Sort by Impact Factor and click on the Sort Again button.

To locate the impact factor within a specific subject category.

  • Select Journal Citation Reports
  • Under Select an Option choose View a group of journals by: and then choose subject category from the drop down menu. Click Submit
  • Select one or more subject categories from the list and click Submit
  • The list of results is sorted by Journal title; change the sort option to Impact Factor to rearrange the results and click Sort Again
  • Click on a journal title to go through to the Journal Information page, where there is a Category Data button - click it to bring up the impact factors for the journals within that subject category.

For help using any of the tools mentioned in this page, please contact your Liaison Librarian .