Impact Factor
The journal impact factor is a measure of the frequency
with which the average article in a journal has been cited in a particular year.
The impact factor helps you evaluate a journal's relative importance, especially
when you compare it to others in the same field.
To calculate the five year Impact Factor, citations are counted
in 2012 to the
previous five years and divided by the source items published in the previous
five years.© 2012 Thomson Reuters, 2012 Journal Citation Reports®