Impact Factor is a measure of the frequency with which the ‘average article’ in a journal has been cited in a particular year. The Journal Citation Reports (JCR®) impact factor, published by Thomson Scientific, is basically a ratio between citations and recent citable items published. Thus, the impact factor of a journal would be calculated by dividing the number of all current citations of source items published in the journal during the previous two years by the number of articles the journal published in those two years. By providing some qualification of the quantitative data in the JCR®, the impact factor is an important tool for journal evaluation….more at MEI Online