title: Trends in Authorship Patterns in High-Impact Radiology Publications, 1980-2013.
abstract: OBJECTIVE
  Concerns have been raised about authorship inflation in medical literature. The purpose of this study was to determine how the number of authors per radiology article has changed over time with regard to study type and geographic factors.
  
  
  METHODS
  We collected data on study type, authorship count, and the country of the corresponding author for a sample of articles published in Radiology, American Journal of Roentgenology, and European Radiology in 1980, 1990, 2000, and 2013. Only original research and review articles were considered. We computed trends in the mean number of authors per article for each journal and compared authorship trends between study types and geographic region. The study did not involve human subjects and was therefore exempt from institutional board review at our institution.
  
  
  RESULTS
  A total of 682 articles were reviewed, of which 572 were original research articles (83.9%) and 110 review articles (16.1%). The overall number of authors per article doubled from 3.6 in 1980 to 7.3 in 2013 (P < .001). From 1990 to 2013, the largest absolute increase in authorship count was in Radiology (4.4-8.1, 84.1%, P < .001). The largest increase in authorship occurred in original research articles (3.7-7.8, 111%, P < .001). Although authorship counts were greatest in Asia over most study period, growth in authorship count was highest in Europe.
  
  
  CONCLUSIONS
  Authorship count has dramatically increased in radiology journals in the last 3 decades, particularly in original research articles and in Europe.
authors.affiliation: Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115. Electronic address: nkapoor@partners.org.
authors.forename: Neena
authors.initials: N
authors.lastname: Kapoor
authors.affiliation: Department of Family Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio.
authors.forename: Matthew V
authors.initials: MV
authors.lastname: Abola
authors.affiliation: Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts; Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts; National Bureau of Economic Research, Cambridge, Massachusetts.
authors.forename: Anupam B
authors.initials: AB
authors.lastname: Jena
authors.affiliation: Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115.
authors.forename: Stacy E
authors.initials: SE
authors.lastname: Smith
mesh_terms: D001208:Asia; D001319:Authorship; D015706:Bibliometrics; D035843:Biomedical Research; D005060:Europe; D005260:Female; D006801:Humans; D009656:North America; D010506:Periodicals as Topic / Q000639:trends*; D011871:Radiology / Q000639:trends*; D012107:Research Design; D012196:Review Literature as Topic
keywords: Honorary authorship; ethics; gift authorship