An analysis of more than 26 million scientific studies published by more than 4 million researchers between 2000 and 2015 found that as of 2015, the top 1% of most cited authors accounted for 21% of all citations.
This citation disparity has become more extreme over time, and the share of citations from US-based scientists has been falling.
Research papers are considered an important measure of the importance of a paper, and university and funding administrators often take them into consideration when deciding whether to offer a researcher’s term or grant.
In his analysis 1, published in the Proceedings of the National Academy of Sciences, sociologist Mathias Nielsen at the University of Copenhagen, Aarhus, and Bibliometrician Jens Peter Anderson at Aarhus University, Denmark, peer reviewed 118 scientific topics in international web science science .
Increase in inequality
Researchers designed an algorithm to create a profile of every author with five or more publications. He then found every instance in which each author’s papers were cited, combining all of them together to form a citation score.
This allowed the team to identify elite ‘elite citation’ – the top 1% most cited author – and see how many citations each member of this group received in a year. Between 2000 and 2015, the proportion of citations taken for this elite increased from 14% to 21%.
Although most areas showed some growth, the greatest rise of inequality occurred in physics and astronomy. In these areas, the proportion of citations given to the elite increased from 20% in 2011 to about 22% in 2012, and continued to grow.
Nielsen and Anderson are not sure why this leap took place, but they think it may be the result of an increasing number of paper-making collaborations with hundreds of authors.
Widely anticipated studies in any field, such as the announcement of the discovery of the Higgs Boson, may present more citations than those that do not promote as much, say the author.
And because only a limited time is available to use physics and astronomy research infrastructure such as particle accelerators and telescopes, Nielsen says, some scientists who have access will often be cited.
Cassidy Sugimoto, an informatics researcher at Indiana University Bloomington, believes the increasing number of collaborations may indicate some impact.
In the last century, cooperation at all levels and in all fields of science has been steadily increasing. She notes that in the Nielsen and Anderson study, when the authors were divided so that each author would get a fraction of the paper, the overall inequality in citation shares remained constant. “I see it as a reorganization and reorganization of science,” says Sugimoto. “It highlights that teams are almost ubiquitous.”
Nielsen and Anderson also found a decrease in the share of citations given to papers written in the United States, and an increase in the marks given to letters written in Western Europe and Australia. The Elite Citation Elite had the highest concentrations of researchers in the Netherlands, the United Kingdom, Switzerland and Belgium.
Vincent Lariviar, a bibliologist at the University of Montreal, Canada, is not surprised. He points out that the proportion of American researchers’ papers is declining, as well. According to the Science and Engineering Indicators 3 of the US National Science Foundation, the United States accounted for 29% of all papers published in 1998, but only 17% in 2018.
Larivare wondered whether excluding scientists with fewer than five publications could affect the authors’ findings. For example, PhD students and postdocs may publish only one or two papers before leaving education for jobs in industry, government, or the nonprofit sector.
If the number of such authors is increasing, this may account for some apparent increase in commendation concentration among senior scientists.
Anderson says that he and Nielsen had to limit their analysis to authors with multiple publications due to data-quality reasons.
The need for each profile to include multiple publications in the same field helped their algorithms differentiate between authors with similar names; For everyone, who had the same publication, it made the analysis very difficult.
Nevertheless, both agree that it will be helpful to understand the trends surrounding ‘transient’ writers. “If that group is growing, that makes the concentration at the top even more serious,” Nielsen says.
The authors note that their data set probably includes some highly cited authors, whose influence has been generated by excessive self-citation, citation ghost farms’ and ghostwriters.
Other disparities
Sugimoto is not too concerned about the commendation disparity between established authors.