What is "impact factor"

n. A measure reflecting the average number of citations to recent articles published in an academic journal, used as an approximation of the relative importance of a journal within its field.

The impact factor (IF) of an academic journal is a measure reflecting the yearly average number of citations to recent articles published in that journal. It is frequently used as a proxy for the relative importance of a journal within its field, with journals with higher impact factors deemed to be more important than those with lower ones. The impact factor was devised by Eugene Garfield, the founder of the Institute for Scientific Information. Impact factors are calculated yearly starting from 1975 for those journals that are indexed in the Journal Citation Reports. Web of Science (previously known as (ISI) Web of Knowledge) is publishing Journal Citation Reports.

Web of Science is part of Thomson Reuters science and intellectual property division. On July 11, 2016, Thomson Reuters announced that it is selling its science and intellectual property division for US$3.55 billion in cash to a pair of private equity fund managers. The buyers are private equity funds affiliated with Toronto-based Onex Corp. and Baring Private Equity Asia.