Title: Prevalence of gift and ghost authors in Cochrane reviews
The study aimed to determine the prevalence of gift and ghost authors in Cochrane reviews and to investigate possible predictors of inappropriate authorship.
An Internet-based survey was sent in April 2019 to 1,226 first authors of Cochrane reviews published between October 2016 and December 2018. Three reminders were sent. The survey consisted of 27 questions and focused on demographics, knowledge about the authorship criteria, the contribution of the first author and the coauthors, and thegeneral experience of following the authorship criteria in their academic work. The responses were anonymized prior to data extraction.
A total of 666 out of 1,226 (54%) first authors completed the survey. The prevalence of gift authors was 41%,whereas, the prevalence of ghost authors was 2%. Of the first authors, 15% were not aware of the authorship criteria from the International Committee of Medical Journal Editors (ICMJE). In a multivariable analysis, factors associated with the existence of gift authorship were not being aware of the ICMJE authorship guidelines (p=0.006), an increasing number of authors (p<0.001), and offering an illegitimate authorship previously in the first author’s academic career (p=0.005).
A substantial proportion of Cochrane reviews showed evidence of gift authorship, while ghost authorship was less prevalent. A considerable amount of authors were not aware of the ICMJE authorship criteria.
Title: Increasing number of authors in Cochrane reviews
To investigate authorship trends in Cochrane reviews; both overall and within each of the editorial groups; and to examine if the authorship criteria from the International Committee of Medical Journal Editors (ICMJE) were met for Cochrane reviews with more than 15 authors based on the text in the section “Contributions of authors”.
We included Cochrane reviews from 1996 to 2018.
We included a total of 7,447 Cochrane reviews. The median number of authors per Cochrane review was 3 in 1996 (IQR 2-3, range 2-3), 4 in 2007 (IQR 3-5, range 1-13), and 5 in 2018 (IQR 4-7, range 2-22). Within each of the 55 editorial groups, the total number of authors either increased (47%) or was unchanged (53%). A total of 27 Cochrane reviews had more than 15 authors. Based on the text in “Contributions of authors”, 59% (16/27) of the reviews with more than 15 authors had authors that did not fulfill the ICMJE authorship criteria. However, the text in “Contributions of authors” was often difficult to interpret.
The number of authors per Cochrane review gradually increased from 1996 to 2018. The ICMJE authorship criteria were most likely not met by all authors in more than half of the reviews with more than 15 authors.