Cliques of mathematicians at institutions in China, Saudi Arabia and elsewhere are believed to have artificially inflated the citation numbers of colleagues. In addition, they published low-quality work that repeatedly cited colleagues’ essays – which caused them to rise in the relevant rankings. This is the result of an as yet unpublished analysis by the science journal Science was viewed. As a result, universities – some of which apparently don’t even have mathematics departments – publish more highly cited mathematical papers each year than schools with high reputations in the field, such as Stanford and Princeton.
According to experts, these so-called “citation cartels” appear to be trying to improve the rankings of their universities. “The stakes are high – promotions or relegations in the rankings can cost or earn universities tens of millions of dollars,” says Cameron Neylon, a professor of research communication at Australia’s Curtin University. “It’s inevitable that people will bend and break the rules to improve their position.” In response to such practices, citation analysis company Clarivate excluded the entire mathematics field from its latest ranking of highly cited papers, published in November 2023.
Many articles appear in journals that no serious mathematician would read
The new analysis is the work of Domingo Docampo, a mathematician at the Spanish University University of Vigo, who has been working on university ranking systems for a long time. In recent years, Docampo has noticed that Clarivate’s Most Cited Researchers (HCR) list has gradually been taken over by lesser-known mathematicians. “There were people who published in journals that no serious mathematician would read, whose work was cited in articles that no serious mathematician would read, and who came from institutions that no one in mathematics knows about,” he says. So he decided to examine Clarivate’s data from the last 15 years to find out which universities were publishing highly cited papers and who was citing them.
The data shows that between 2008 and 2010, institutions such as the University of California, Los Angeles (UCLA) and Princeton published the most highly cited mathematical papers, with 28 and 27, respectively. The one percent of the specialist articles that are cited most frequently in a year fall into this category. However, in 2021 to 2023, the prestigious universities were displaced by institutions with little mathematical tradition, many of which can be found in China, Saudi Arabia and Egypt. In the most recent period, China Medical University in Taiwan topped the list with 95 highly cited mathematical papers. A decade earlier, this institution was not represented in the list with a single paper. UCLA, on the other hand, recently only had one highly cited paper.
Docampo found patterns that suggested citation cartels were at work. Most tellingly, the citations to the top papers often come from researchers at the same institution as the authors of the cited paper. For example, China Medical University and King AbdulAziz University, which had 66 top publications between 2021 and 2023, published hundreds of studies that cited highly cited papers. Docampo also found that the studies that referred to highly cited papers were often published in questionable journals that may be more accepting of dubious citation practices.
Scientists not involved in Docampo’s analysis confirm that all of this points to widespread citation manipulation. “There are a number of researchers who try to artificially increase their citation frequency in a way that in no way reflects their scientific quality,” says Helge Holden, chairman of the Abel Prize committee, one of the most prestigious Awards in mathematics. “One can only condemn that.”
Yueh-Sheng Chen, senior secretary of China Medical University, says his university has not participated in the practice. “We know nothing about targeted quotes and are not involved in such manipulations.” The involvement of “internationally renowned experts and scientists from areas such as applied mathematics” is part of the university’s interdisciplinary approach, he adds. King AbdulAziz University did not respond to Science after a comment.
Clarivate declined to comment on the matter. In explanations of his decision, mathematicians from the youngest HCR list However, the company explains that it is concerned about attempts to raise its own status through publication and citation manipulation. Mathematics is particularly susceptible to manipulation because the field is small, the company writes. “The average publication and citation rate… is relatively low, so small increases in publications and citations can distort the presentation and analysis of the entire field.”
“We very much regret that no other option was seen than to no longer perform the mathematics at all”
But citations are also manipulated in other disciplines, says Félix de Moya Anegón, a bibliometrician at the University of Granada – it’s just not as visible. Ilka Agricola, chairwoman of the International Mathematical Union’s Committee on Electronic Information and Communication, fears that the impression could be created that the field has been infiltrated by “fraudulent scientists.” She very much regrets that Clarivates “seemed no other option than to no longer perform the mathematics at all.”
Clarivate says it has “sought advice from external experts… to discuss our future approach to analyzing this area.” Docampo is already working on a refined metric that weights citations based on the quality of the citing journals and institutions.
Other researchers say that citation manipulation is simply a symptom of a flawed rating system. Quotes and similar metrics are not sophisticated enough to evaluate individual performance, says Ismael Rafols, a researcher at the Center for Science and Technology Studies at Leiden University, and people will always find ways to manipulate the system. Helge Holden from the Abel Prize Committee agrees: “The bottom line is that citations are not a good measure of scientific quality.”
This article comes from the science magazine Science. It was translated and reprinted with permission from AAAS. It is not an official translation of the Science-Editorial staff. In case of doubt, the English original, published by AAAS, applies. German adaptation: huh