Retracted Scientific Papers Persist in New Studies, Citations

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Teachers in grade school use a popular lesson to illustrate the power of words: they squeeze all the toothpaste—or words—out of the container and then ask children to put it back in. It’s a powerful and visually stimulating way to demonstrate that words cannot be taken back once they are spoken.

This is true of written words, as well. In scientific publishing, articles can be retracted, but, as information sciences expert Jodi Schneider has shown in her latest paper, misinformation from retracted studies persists for years.

Schneider’s study focused on one specific paper published in 2005 by Wataru Matsuyama et al., that found omega-3 fatty acids to be helpful in reducing inflammatory markers in patients with chronic obstructive pulmonary disease (COPD). The paper, published in the journal Chest, was retracted in 2008 for reporting on falsified clinical trial data. However, 11 years later, the original paper continues to be cited in other research—with citations actually increasing since its retraction.

“Ensuring that retracted articles don't continue to be cited as reliable research is important not just for scientists but also for public confidence in scientific research,” Schneider said. "A scientific paper that is right is like a brick to build walls of evidence we can rely on.”

Schneider's analysis covered 148 direct citations of the COPD paper from 2006-2019 and 2,542 second-generation citations. The retraction is not mentioned in 96% of direct post-retraction citations. In fact, only 5 direct citations mention the retraction, with all describing it as “poor research.”

Analyzing the context as well as the number of citations, Schneider found that more than 41% of the post-retraction citations of the COPD paper that did not mention the retraction went on to describe the paper in detail.

Retractions may be rare—about 4 per every 10,000 papers—but they are incredibly important. Today’s digital library, however, complicates communication around retraction status of a paper.

Some websites and databases, such as PubMed, make retraction notices easily visible, but others, including Google Scholar, Web of Science and Scopus, do not. In fact, a simple Google search for Matsuyama’s COPD paper by title yields the article as originally published in Chest. The word “retraction” does not appear anywhere on the webpage. Schneider's research confirms that the paper’s retraction status is not indicated on any available PDF or HTML full-text.

“Publishers must bear responsibility for clearly marking retracted papers, by watermarking their own copies in all formats (e.g., PDF, HTML, EPUB); by prominently linking to the retraction notice wherever the paper appears, including the article landing page and issue table of contents; and by providing accurate metadata, including the retraction status, to partners,” Schneider writes in her own paper, published in Scientometrics.

The consequences of retracted papers go far beyond scientific publishing. Some papers gain mainstream media attention—if that paper is then retracted, information directed to the general public is usually not corrected. Schneider’s work confirms that has happened with Matsuyama’s COPD paper.

“Information about the purported treatment benefit has flowed widely to researchers, but also to clinical audiences, through educational modules, clinical nutrition reviews and textbooks, including direct translation of educational modules from English into other languages,” she writes in her paper. “It is conceivable that, based on the publicity of the outcomes from the Matsuyama study, some individuals with COPD may perceive omega-3 supplements as a possible natural alternative to pharmacotherapy.”

The most famous example we have of continued misinformation persisting in the general public is the now-retracted journal article that once linked the MMR vaccine to autism. Although debunked, the argument is still used among those who express concerns and even conspiracy theories about the MMR vaccine.

Schneider said best practices for journals should include ensuring every retraction notice is publicly available and establishing a convention for how to flag an article that is retracted. She also recommends the development of a standard set of metadata regarding retractions that would be attached to articles and use of a taxonomy of statuses, such as retraction or expression of concern.

“Database providers and aggregators must demand up-to-date metadata from publishers, and should consider partnering with alternative metadata producers,” Schneider writes. “Parties responsible for the retraction, including authors for self-retraction and investigative committees for misconduct-related retraction, should search citation databases and notify citing authors directly to the retraction notice, for follow-up action.”

Information sciences students at the University of Illinois at Urbana-Campaign, where Schneider is a professor, have built a prototype tool called ReTracker that automatically checks for retractions among articles that scholars compile in their online libraries by using data from PubMed. Zotero, a popular reference-management software system used for managing bibliographic data and research materials, has also developed a similar tool.