Journal Impact Factors Journal Impact Factor is from Journal Citation Report (JCR), a product of Thomson ISI (Institute for Scientific Information). JCR provides quantitative tools for evaluating journals. The impact factor is one of these; it is a measure of the frequency with which the "average article" in a journal has been cited in a given period of time. The impact factor for a journal is calculated based on a three-year period, and can be considered to be the average number of times published papers are cited up to two years after publication. For example, the impact factor 2008 for a journal would be calculated as follows: A = the number of times articles published in 2006-7 were cited in indexed journals during 2008 B = the number of articles, reviews, proceedings or notes published in 2006-7 impact factor 2008 = A/B (note that the impact factor 2007 will be actually published in 2008, because it could not be calculated until all of the 2008 publications had been received. Impact factor 2008 will be published in 2009)
The lists of Impact Factors have been removed from this site due to copy right violations. Sci-Bytes provides ranking and impact factor for selective journals. The list is located here: http://www.sciencegateway.org/rank/index.html MIT Biology Hyertextbook