title: How well are journal and clinical article characteristics associated with the journal impact factor? a retrospective cohort study.
abstract: OBJECTIVE
  Journal impact factor (JIF) is often used as a measure of journal quality. A retrospective cohort study determined the ability of clinical article and journal characteristics, including appraisal measures collected at the time of publication, to predict subsequent JIFs.
  
  
  METHODS
  Clinical research articles that passed methods quality criteria were included. Each article was rated for relevance and newsworthiness by 3 to 24 physicians from a panel of more than 4,000 practicing clinicians. The 1,267 articles (from 103 journals) were divided 60∶40 into derivation (760 articles) and validation sets (507 articles), representing 99 and 88 journals, respectively. A multiple regression model was produced determining the association of 10 journal and article measures with the 2007 JIF.
  
  
  RESULTS
  Four of the 10 measures were significant in the regression model: number of authors, number of databases indexing the journal, proportion of articles passing methods criteria, and mean clinical newsworthiness scores. With the number of disciplines rating the article, the 5 variables accounted for 61% of the variation in JIF (R(2) = 0.607, 95% CI 0.444 to 0.706, P<0.001).
  
  
  CONCLUSIONS
  For the clinical literature, measures of scientific quality and clinical newsworthiness available at the time of publication can predict JIFs with 60% accuracy.
authors.affiliation: Health Information Research Unit, McMaster University, CRL 125, 1280 Main Street West, Hamilton, ON, Canada. lokkerc@mcmaster.ca
authors.forename: Cynthia
authors.initials: C
authors.lastname: Lokker
authors.forename: R Brian
authors.initials: RB
authors.lastname: Haynes
authors.forename: Rong
authors.initials: R
authors.lastname: Chu
authors.forename: K Ann
authors.initials: KA
authors.lastname: McKibbon
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Wilczynski
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Walter
mesh_terms: D000043:Abstracting and Indexing / Q000706:statistics & numerical data; D015331:Cohort Studies; D055811:Journal Impact Factor; D018156:Journalism, Medical / Q000592:standards; D015233:Models, Statistical; D012044:Regression Analysis; D012107:Research Design; D012189:Retrospective Studies