title: Equal contributions and credit: an emerging trend in the characterization of authorship in major spine journals during a 10-year period.
abstract: OBJECTIVE
  The practice of giving certain authors equal credit in scientific publications has become increasingly common in some medical specialties. However, whether this trend also exists in major spine journals remains unclear. This study aimed to investigate the prevalence and characteristics of the practice of giving authors equal credit in major spine journals.
  
  
  METHODS
  Manual searches were performed to identify original research articles with equally credited authors (ECA) published between January 1, 2004 and December 31, 2013 in three major spine journals: Spine, European Spine Journal, and The Spine Journal. The number of authors with ECA and their positions in the byline, total number of authors, year of publication, and country of origin were analysed.
  
  
  RESULTS
  The practice of ECA was found in all three journals. Articles with ECA comprised a greater proportion of the total number of publications in each journal in 2013 versus 2004 (Spine, 7.2 vs. 0.2%; European Spine Journal, 7.5 vs. 0.0%; and The Spine Journal, 6.2 vs. 0.0%). There was a statistically significant increasing trend in the annual proportion of papers with ECA for all three spine journals (p < 0.0001). The practice of ECA was applied in nearly every position in the byline, and the first two authors received equal credit in most cases. Articles with ECA were published by authors from various countries and regions around the world. However, none of the three spine journals provided specific guidance on this practice in their author instructions.
  
  
  CONCLUSIONS
  The practice of ECA in original research articles is increasingly common in major spine journals. A guideline for authors regarding when and how to designate equal credit is warranted in the future.
authors.affiliation: Department of Orthopaedics, Navy General Hospital, NO. 6 Fucheng Road, Beijing, 100048, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Jia
authors.affiliation: The Third Clinical College, Southern Medical University, Guangzhou, China.
authors.forename: Yaohong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Orthopaedics, Navy General Hospital, NO. 6 Fucheng Road, Beijing, 100048, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Orthopaedics, Navy General Hospital, NO. 6 Fucheng Road, Beijing, 100048, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
authors.affiliation: Department of Orthopaedics, Navy General Hospital, NO. 6 Fucheng Road, Beijing, 100048, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China.
authors.forename: Xiyan
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Orthopaedics, Panyu Hospital of Chinese Medicine, Guangzhou, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Orthopaedics, Navy General Hospital, NO. 6 Fucheng Road, Beijing, 100048, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: He
authors.affiliation: Department of Orthopaedics, Navy General Hospital, NO. 6 Fucheng Road, Beijing, 100048, China. ruandikengh@163.com.
authors.forename: Dike
authors.initials: D
authors.lastname: Ruan
mesh_terms: D001319:Authorship; D006801:Humans; D009985:Orthopedics; D010506:Periodicals as Topic / Q000706:statistics & numerical data*; D011643:Publishing / Q000639:trends*; D013131:Spine
keywords: Authorship; Equal contributions; Publications; Spine