Multi-authorship and research analytics

Report highlights the distorting effect of hyper-authored articles on citation and impact analysis.

A report released by the Institute for Scientific Information at Clarivate Analytics identifies a growing number of research articles in the Web of Science with 1,000 or more unique authors across more than 100 different countries. 

The report explores the impact of complex hyper-authorship by author, country and discipline.  Prior to 2000, the maximum number of authors on a single article rarely exceeded 500. In 2004, a paper with 2,500 authors was published. The record is now held by a 2015 article by the ATLAS team on the Higgs Boson (5,153 authors at more than 500 institutional addresses).

The count of countries listed among author affiliations has similarly increased. International collaboration was relatively scarce in the 1980s but has grown rapidly: more than half of the articles attributable to any one country now have a co-author from another (Adams, 2013).

The report looked at about 15 million articles indexed in Web of Science between 2009-2018.

Key findings

  • A small but growing number of hyper-authored research articles are driving seriously elevated citation rates and may skew any impact analysis of the scientific literature
  • Complex authorship (many people, many countries) has continued to rise in the last five years with the dramatic emergence of articles with more than 100 countries 
  • The combination of many authors plus many countries drives a complex authorship pattern that differs from more typical academic papers and leads to elevated citation rates
  • One additional country on an article has a greater citation benefit than one additional author
  • Data resulting from articles with hyper-authorship (100+ authors and/or 30+ countries) produces erratic data that should be removed from analysis at a national and institutional level. 
  • The most frequent number of authors on an article is three and 95% of articles analysed have ten or fewer authors
  • 99% of articles have authors from five or fewer countries
  • Author and impact patterns can vary hugely between disciplines (e.g. biomedical sciences appear commonly now to require large teams) 


Articles with more than ten authors should be acknowledged and separately described because they will influence interpretation; and articles with hyper-authorship be treated differently with a strong argument for removing these data from all analyses at a national and institutional level.
Dr Jonathan Adams, Director, Institute for Scientific Information, Web of Science Group