Trends in authorship of original articles in three high-impact medical journals: a decade-by-decade analysis from 2003 to 2023

Background: The study analyzes trends in the average number of authors per “original article” in three high-impact scientific journals (The Journal of the American Medical Association [JAMA], The New England Journal of Medicine [NEJM], and The Lancet [TL]) over two decades. Methods: The mean number of authors per publication was calculated and compared across the two decades. Comparisons were made both by publication year and by journal. Results: A total of 1645 articles were included: 529 (39.15%) from JAMA, 627 (38.11%) from NEJM, and 510 (31.0%) from TL. The mean number of authors in 2003 was 10.5 (interquartile range [IQR] 5-12, range 1-382), in 2013 it was 20.4 (IQR 9-21, range 1-596), and in 2023 it was 40.5 (IQR 15-33, range 2-785). Significant differences were found in the number of authors between years, with a rising trend in the mean (p < 0.001). A higher increase rate in authors was observed compared to the collected literature, possibly due to the exclusive selection of original articles. As a secondary result, significant differences were found in the number of authors between TL and NEJM (p = 0.003), as well as between TL and JAMA (p < 0.001). No significant difference was found between JAMA and NEJM (p = 0.180). Conclusions: The mean number of authors per original article in the journals JAMA, NEJM, and TL has increased from 2003 to 2023, with a mean of 9.84 between 2003 and 2013 and 20.1 between 2013 and 2023. Our findings align with the trend of increasing authorship observed in the collected literature.