Data from more than 34 million research articles drawn from Scopus have been reviewed to determine how the number of authors on scientific papers has changed over the past two decades. The investigation by The Economist revealed that from 1996–2015 the average number of authors per paper grew from 3.2 to 4.4, with the average number of papers being published by a researcher increasing from 2.1 to 2.3. However, an author’s overall paper-writing contribution (calculated as the number of papers/number of authors who published in a given year) fell from 0.64 to 0.51 during the same time.
The authors suggest that one reason behind this trend may be an increase in guest authorship, in which high-profile individuals are named on a paper having contributed little to the work reported. They provide examples of impressive yet improbably prolific publication lists achieved by some authors.
The investigation also highlighted the trend in exceptionally long author lists for papers from large collaborative projects. For example, a paper reporting work on the Higgs boson named over 5,000 co-authors. The Economist question whether it can be said that each individual made a substantial contribution to the work, which is one of the four criteria required for authorship as recommended by the International Committee of Medical Journal Editors, and suggest the meaning of authorship in these circumstances is still unclear.