1. Human Biology and Medicine
  2. Microbiology and Infectious Disease
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Meta-Research: Gender inequalities among authors who contributed equally

  1. Nichole A Broderick  Is a corresponding author
  2. Arturo Casadevall  Is a corresponding author
  1. University of Connecticut, United States
  2. Johns Hopkins School of Public Health, United States
Feature Article
Cite this article as: eLife 2019;8:e36399 doi: 10.7554/eLife.36399
4 figures, 1 table and 2 additional files


Figure 1 with 1 supplement
Proportion of various gender combinations among joint first authors in scientific papers published between 1995 and 2017.

We studied papers in which two or more authors shared the first author position: ‘fm’, ‘ff’, ‘mf’ and ‘mm’ represent papers in which two authors shared the first author position, with the actual order of the authors being female-male, female-female, male-female and male-male. For papers in which more than two authors shared the first author position, ‘all f’ means that all these authors were female, ‘all m’ means they were all male, and ‘f+’ or 'm+' means that the first author listed in a mixed-gender combination was female or male respectively. The plot shows that the proportion of combinations in which a male author is listed first (various shades of blue) is decreasing over time.

Figure 1—source data 1

Raw data for Figure 1.

Excel database of the papers examined in this study. Grey shaded rows indicate the papers excluded from analysis when gender identification was not able to be determined.

Figure 1—figure supplement 1
Distribution of papers analyzed per year in this study.
Gender bias in the first author position over time.

Temporal trend in gender bias among two equally contributing authors of different gender: the y-axis is log (p/(1 p)) where p is the probability of bias; the x-axis is publication year. In the absence of bias, log (p/(1 p)) would be zero.

Figure 2—source data 1

Data analysis tables used for Figure 2.

Figure 2—source data 2

Data analysis log.

Figure 2—source data 3

Data management file for data analysis.

Percentage of papers with two or more authors contributing equally as a function of time.

Points denote the percentage of papers with where more than two authors claimed equal contribution. Trendline R2 value as 0.4857.

Gender bias in first authorship by year and geography.

Predicted probabilities of male first authorship by year for three geographical regions (USA: blue; Europe: green; Other: red) among papers with two equally contributing authors of different gender (N = 972).

Figure 4—source data 1

Data analysis tables used for Figure 4.

Figure 4—source data 2

Data analysis log.

Figure 4—source data 3

Data management file for data analysis.



Table 1
Summary of data on authors listed a contributing equally.
Article statisticsContributed equally = 2Contributed equally > 2
Journal titleTotalUnknownUsablemmmffffmm firstf firstall Mall f
Biophysical J1012996017595030
Cell Reports10511044112111512931
Curr Biol103499412314122421
J Biol Chem3002827299523548151166
J Cell Bio101398223514174420
J Clin Invest12161154219111912660
J Exp Med2101319765402630108117
J Immunol308102988976594816352
PLOS Bio1109101391813176530
PLOS Comp Bio95293451461134100
PLOS Genet186817852261623203560
PLOS Negl Trop Dis105699321321198420
PLOS Pathogen17971723539332520974
Initial search*570570350220000
  1. *These papers are from the early searches used to identify the variables in this study and only mf and fm numbers were recorded. These 57 papers were removed from subsequent analysis.

    †Miscellaneous includes the following journals; the number of articles in which two or more authors made equal contributions is shown in parenthesis for each journal. American Journal of Pathology (1); Angewandte Chemie (17); Biochemical and Biophysical Research Communications (2); Blood (1); BMC Bioinformatics (1); BMC Proceedings (1); BMC Systems Biology (1); Brain Pathology (1); Cancer Research (2); Cell (6); EMBO Journal (4); European Journal of Immunology (1); FEBS Letters (27); Genes and Development (5); Genome Research (1); Hepatology (1); International Journal of Cancer (2); Journal of Bone and Mineral Research (2); Journal of Cell Science (2); Journal of Molecular Biology (1); Journal of Physiology (2); Memórias do Instituto Oswaldo Cruz (15); Nature Biotechnology (1); Nature Cell Biology (1); Nature Genetics (15); Nature Materials (1); Nature Medicine (4); PLOS One (1); Protein Science (1).

Table 1—source data 1

All data organized by journal, author/gender category, and year.


Data availability

Source data files for all figures have been provided along with the complete raw dataset.

Additional files

Supplementary file 1

Characteristics of journals chosen for this study.

Transparent reporting form

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