2 Open Access publishers accused of over-citing themselves

Two major scientific publishers of open access research – that is, free to read outside of the paywall – have been accused of over-citing articles previously published in their own journals.

A study published in May ahead of the peer review process on the preprint server SocArXiv suggests that high self-citation rates may have increased the journal impact factor (JIF) of titles published by MDPI and Frontiers in recent years.

The study authors examined the citation patterns of 8,360 journals published by the 20 largest for-profit academic publishers between 1997 and 2021. They found that articles published by Frontiers and MDPI titles contained more self-citations than journals from other publishers.

Citations are important in academia because they are used to calculate metrics such as JIF, which are often incorrectly used to judge researchers and their work.

“The propensity to self-cite is very similar for all journals of all publishers except for Frontiers and MDPI, which are two clear outliers,” says study co-author Marco Seeber, a sociologist and professor of public policy at the University of Agder. He notes that the self-citation of studies published in the previous 5 calendar years, which are used to calculate the JIF, is particularly high.

“It is difficult to explain the concentration of citations in this window and across publishers other than by manipulation,” says Matt Hodgkinson, a research integrity specialist and member of the Publications Ethics Committee who was not involved in the new study. “It’s clear that perverse incentives affect citation behavior on a large scale,” he says, adding that the study is “well-designed and sophisticated.”

Seeber’s previous research indicated that researchers in a dozen countries cite their own papers at unusually high rates, a phenomenon he and his colleagues attribute to policies in those countries that encourage such citation practices. In 2018, they reported that researchers in Italy increased their citation rates after a controversial 2010 law came into force that required academics to meet certain productivity thresholds to be eligible for promotion.

Editors have been accused in the past of asking authors to add citations to previously published articles in order to artificially boost their journals’ citation metrics.

“Publishers and editors must never require or routinely ‘suggest’ that authors cite their journals in order to have their articles accepted,” says Hodgkinson. “[Even] if they were authors trying to curry favor and strengthen [JIF] of their target journal or editors who go rogue, publishers still have a responsibility to oversee processes to ensure that citations are not manipulated.”

For him, it is important that all citation-based metrics ignore or explicitly adapt to self-citation, be it by institution, editor, journal, or publisher. “In addition to highlighting and controlling citation manipulation, the broader solution is to stop evaluating authors and institutions based on the impact factor of the journals in which they publish,” he says.

Giulia Stefenelli, chair of MDPI’s scientific board, said in an email that the publisher maintains a transparent self-citation policy. “Any detected manipulation of citations is closely monitored and authors and reviewers are required to follow strict rules. Reviewers and academic editors are responsible for verifying the relevance of citations. MDPI never encourages the addition of journal citations to any article as this would be unethical.”

A Frontiers spokesman said in an email that the study uses an “unnecessarily convoluted methodology” to calculate self-citations and links growth in publication output to self-citations. Our “research integrity team has implemented specific controls that systematically monitor unethical citation practices. As with all serious violations, any reviewer or editor caught attempting such activity will be fired immediately,” the spokesperson said.