Impact factors are calculated and published annually in the Journal Citation Reports by Thomson Reuters. The Journal Citation Reports are available online starting with the 2009 edition.
Previous years are available in hard copy from the Reserve desk in the library (ask for the JCR at the Circulation Desk). Ellis Library also has paper copies available at: Ready Reference Z7403 .S32
The impact factor is the the best known quantitative indicator of journal quality. The higher the impact factor, the better the journal. Read more about how impact factors are calculated.
There are many other indicators of journal quality available. Find more on our Promotion & Tenure Resources for Research/Scholarship Assessment page.