Introduction: The emphasis on publications for promotion in academic medicine would lead one to the theory that authorship numbers would increase proportionally with this emphasis. To investigate authorship trends across a number of periodicals, we performed a descriptive study comparing two full years of published articles spaced ten years apart from five medical journals.
Methods: Physician reviewers each reviewed all articles of one medical journal for the 1995 and 2005 publication years. Reviewed journals included Academic Emergency Medicine (AEM), Annals of Emergency Medicine (AnnEM), Annals of Internal Medicine (AIM), Journal of Trauma (JT), and New England Journal of Medicine (NEJM). Data collected for each article were number of authors, ordinal number of the corresponding author, type of study described, whether the described study was a multicenter trial, whether authorship listed included a "study group," and whether any author was also an editor of the journal.
Results: A total of 2927 articles were published in the five journals in 1995, and of these, 1401 (47.9%) were analyzed after the exclusion criteria had been applied; for 2005 a total of 3630 articles were published and of these, 1351 (37.2%) were included in the analysis. Across all five journals the mean number of authors per article increased from 4.66 to 5.73 between 1995 and 2005 (P < 0.0001), and four of the five journals individually had statistically significant increases in the number of authors per article. More articles had a journal editor as an author in 2005 (increased from 7.8% to 11.0%, P = 0.004), though no single journal had a statistically significant increase.
Conclusion: We describe a trend of increasing mean authors, editorial authorship, study groups, and multicenter trials over time with fewer solo authors now publishing original research or case reports. The academic medical community must pursue an authorship requirement consensus to assure that a standard of contribution for all authors on a given paper is met.