Impact factor

ISI Web of Science
Journal citation reports
http://portal.isiknowledge.com/portal.cgi?DestApp=JCR&Func=Frame


the journal impact factor is one way authors and readers judge the quality of a publication. Impact factors have been used to assess academic productivity and are sometimes used to evaluate an author. Journal editors are frequently judged by the change in the impact factor of the journal they edit. What is the impact factor and how is it determined? The impact
factor was created in the 1960s to help select journals for the Science Citation Index (2). Today the journal impact factor comes from the Journal Citation Report (JCR), a product of
Thomson Institute for Scientific Information (ISI) (3). The aim of the factor was to develop a scale that allowed small but important review journals to enter the Science Citation
Index. The impact factor of a journal is calculated using two elements: the numerator, which is the number of citations in the literature in the current year to any items published in a
journal in the preceding 2 years and the denominator, which is the total number of substantative articles published in that journal in the same 2 years.