Journal Impact Factor is:
- The total number of citations in the past two years ÷ number of articles published by that journal in the past two years. (Avg. # of times an article published in that journal has been cited).
- There is a 2 year look-back. 2016 Impact Factors are based on data from 2015 & 2014.
- Data is based on articles indexed in the Web of Science database.
- SCImago also calculates this number and calls it "Cites / Doc 2yrs," based on the Scopus database
A short tutorial on how to find and use Journal Impact Factors can be found here: XXX