What is Impact factor?
A journals's Impact factor is a measure reflecting the number of citations the journal has in a given year. Impact factor is determinated each year, on the basis of the two previous years.
Impact factor is a quantitative tool for comparing journals, and not a measure for the individual published articles.
The more citations a journal has, the higher the Impact factor.
The main source for finding the Impact factor is ISI- Journal Citations Reports. The basis for the calculation is the journals indexed in this database.
Impact factor is often used as a quality measure for research. Impact factor used as this is controversial and should be used with care.
Calculation of the journal Nature's Impact factor in 2009
- Citations of published articles in Nature in 2007+2008=59 996
- Number of published articles in Nature in 2007+2008=1 740
Citations of Nature : Published articles in Nature = Impact factor
59 996 : 1740 = 34,480