Trends in Authorship and Team Science in Major Medical Journals, 2005-2015

Christopher C. Muth,1 Robert M. Golub1


Team science helps address complex research questions by encouraging interdisciplinary and multicenter collaborations. Recognizing the value of team science but also the importance of acknowledging individuals’ contributions, journals may include increased numbers of authors on a byline, group authorship, and special designations to indicate authors who contributed equally to the work when publishing research. This study assessed trends in authorship of research articles published in 3 major medical journals to test the hypothesis that team science is supported by major medical journals and has increased over time.


Research articles published in 2005, 2010, and 2015 in the top 3 general medical journals (JAMA, Lancet, and New England Journal of Medicine [NEJM]) based on current Impact Factor were identified using the Web of Science database. Reviews and meta-analyses were excluded. The number of authors, presence of group authorship, and presence of authors who contributed equally (detected by manual review of the byline for asterisks or other notation and manual assessment of the endnotes for relevant statements) were determined for each article. Trends in these authorship metrics were then assessed by journal over time.


The numbers of articles that met inclusion criteria were 230, 188, and 159 in JAMA; 172, 165, and 178 in Lancet; and 223, 222, and 235 in NEJM for the years 2005, 2010, and 2015, respectively. The median number of authors per article and the proportion of articles with authors who contributed equally increased significantly over time for all journals (Table). The proportion of articles with group authorship increased significantly over time for JAMA but not for Lancet or NEJM.


The number of authors per article and the proportion of articles with authors who contributed equally increased over time in 3 major medical journals. Although limited to top general medical journals, these findings are consistent with previous studies focused on earlier periods and specialty journals. Increases in these authorship metrics may indicate an increase in team science and suggest that major medical journals reflect this trend.

1JAMA, Chicago, IL, USA, christopher.muth@jamanetwork.org

Conflict of Interest Disclosures:

The authors are employed at JAMA, one of the journals included in this study. There are no other conflicts of interest to report.


There was no external funding for this study.

Additional Contributions:

Joseph Wislar, a former employee at JAMA and currently employed at DentaQuest Institute, Williamsport, Pennsylvania, provided statistical consultation.