Editing Impact factor (section)

===Negotiated values===
Results of an impact factor can change dramatically depending on which items are considered as "citable" and therefore included in the denominator.<ref>{{cite journal |vauthors=Adam D |title=The counting house |journal=Nature |volume=415 |issue=6873 |pages=726–9 |date=February 2002 |pmid=11845174 |doi=10.1038/415726a |s2cid=4407346|doi-access=free }}</ref> One notorious example of this occurred in 1988 when it was decided that meeting abstracts published in ''FASEB Journal'' would no longer be included in the denominator. The journal's impact factor jumped from 0.24 in 1988 to 18.3 in 1989.<ref>{{cite journal |vauthors=Baylis M, Gravenor M, Kao R |title=Sprucing up one's impact factor |journal=Nature |volume=401 |issue=6751 |pages=322 |date=September 1999 |pmid=10517624 |doi=10.1038/43768-c1 |s2cid=4356889|doi-access=free }}</ref> Publishers routinely discuss with Clarivate how to improve the "accuracy" of their journals' impact factor and therefore get higher scores.<ref name=PLoS-editorial /><ref name="Brembs_2013" />

Such discussions routinely produce "negotiated values" which result in dramatic changes in the observed scores for dozens of journals, sometimes after unrelated events like the purchase by one of the larger publishers.<ref>{{cite web |access-date=2020-07-14 |title=Just how widespread are impact factor negotiations? |url=http://bjoern.brembs.net/2016/01/just-how-widespread-are-impact-factor-negotiations/ |date=2016-01-08 |vauthors=Brembs B }}</ref>