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Comparing Bibliometric Analysis Using PubMed, Scopus, and Web of Science Databases
Published on: October 24, 2019
Inflated numbers of authors over time have not been just due to increasing research complexity
Stefania I Papatheodorou1, Thomas A Trikalinos, John P A Ioannidis
1Evidence-Based Medicine and Clinical Trials Unit, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece.
Objective:
To examine trends in and determinants of the number of authors in clinical studies.
Study Design And Setting:
We analyzed determinants of the number of authors in 633 articles of randomized trials and 313 articles of nonrandomized studies included in large meta-analyses (seven and six topics, respectively). Analyses were adjusted for topic. We also evaluated 310 randomly sampled case reports that had an abstract and described a single case.
Results:
After adjusting for topic and other determinants, for both randomized trials and nonrandomized studies, the number of authors increased by 0.8 per decade (P<0.001). Topic was a strong determinant of the number of authors; other independent factors included journal impact factor, multinational authorship, and (for randomized trials) article length and sample size. Trials from South Europe (+1.1 authors) and North America (+0.9) and nonrandomized studies from South Europe (+1.8) had more authors than studies from North Europe (P<0.001). For case reports, only geographic location and article length were significantly related with author numbers.
Conclusion:
The number of authors in articles of randomized and nonrandomized studies has increased over time, even after adjusting for the topic, size, and visibility of a study. The academic coinage of authorship may be suffering from inflation.
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