title: Emergency medicine journal impact factor and change compared to other medical and surgical specialties.
abstract: OBJECTIVE
  A journal impact factor represents the mean number of citations per article published. Designed as one tool to measure the relative importance of a journal, impact factors are often incorporated into academic evaluation of investigators. The authors sought to determine how impact factors of emergency medicine (EM) journals compare to journals from other medical and surgical specialties and if any change has taken place over time.
  
  
  METHODS
  The 2010 impact factors and 5-year impact factors for each journal indexed by the Thomson Reuters ISI Web of Knowledge Journal Citation Reports (JCR) were collected, and EM, medical, and surgical specialties were evaluated. The maximum, median, and interquartile range (IQR) of the current impact factor and 5-year impact factor in each journal category were determined, and specialties were ranked according to the summary statistics. The "top three" impact factor journals for each specialty were analyzed, and growth trends from 2001 through 2010 were examined with random effects linear regression.
  
  
  RESULTS
  Data from 2,287 journals in 31 specialties were examined. There were 23 EM journals with a current maximum impact factor of 4.177, median of 1.269, and IQR of 0.400 to 2.176. Of 23 EM journals, 57% had a 5-year impact factor available, with a maximum of 4.531, median of 1.325, and IQR of 0.741 to 2.435. The top three EM journals had a mean standard deviation (±SD) impact factor of 3.801 (±0.621) and median of 4.142 and a mean (±SD) 5-year impact factor of 3.788 (±1.091) and median of 4.297, with a growth trend of 0.211 (95% confidence interval [CI] = 0.177 to 0.245; p < 0.001). By any criterion analyzed, EM journals ranked no higher than 24th among 31 specialties.
  
  
  CONCLUSIONS
  Emergency medicine journals rank low in impact factor summary statistics and growth trends among 31 medical and surgical specialties.
authors.affiliation: Department of Emergency Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. reynoldsjc@upmc.edu
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Reynolds
authors.forename: James J
authors.initials: JJ
authors.lastname: Menegazzi
authors.forename: Donald M
authors.initials: DM
authors.lastname: Yealy
mesh_terms: D016001:Confidence Intervals; D016208:Databases, Factual; D004635:Emergency Medicine / Q000639:trends*; D005260:Female; D013502:General Surgery; D006801:Humans; D007388:Internal Medicine; D055811:Journal Impact Factor; D008297:Male; D008511:Medicine; D010506:Periodicals as Topic; D012015:Reference Standards; D014481:United States