Clarivate will no longer include citations to and from retracted papers when calculating journal impact factors, the company announced today.
The change comes after some have wondered over the years whether citations to retracted papers should count toward a journal’s impact factor, a controversial yet closely watched metric that measures how often others cite papers from that journal. For many institutions, impact factors have become a proxy for the importance of their faculty’s research.
Retractions are relatively rare and represent only 0.04% of papers indexed in Clarivate’s Web of Science, according to the announcement. But the overall retraction rate has risen recently, to about 0.2%, which, along with a decrease in the time it takes to retract papers, motivated the policy change. Nandita Quaderi, the editor-in-chief of Web of Science, said in the announcement the policy would “pre-emptively guard against any such time that citations to and from retracted content could contribute to widespread distortions in the [journal impact factor].”
Clarivate publishes impact factors annually in its Journal Citation Reports. The impact factor represents the number of citations in a given year to works published in a journal in the previous two years, divided by the total number of citable items published in those previous two years.
Starting with the 2025 Journal Citation Reports, Clarivate will exclude citations to and from retracted articles in the numerator, “ensuring that citations from retracted articles do not contribute to the numerical value of” the impact factor, the announcement stated. Retracted articles will remain in the article count for the denominator, “maintaining transparency and accountability.”
“This decision makes intuitive sense but could incentivize against retraction,” bibliometrics expert Reese Richardson said. By keeping retracted items in the denominator of the equation, “this deepens the impact that any given retraction will have on a journal’s [impact factor],” he told us. He said he also wonders “how many journals will actually see a substantial reduction” in impact factor as a result of the change.
Quaderi told us Clarivate would stop counting citations once the paper is retracted, but would keep those that occurred before. The company will continue to use the Retraction Watch Database to flag retracted papers in indexed journals, which it has done since 2022.
Clarivate typically releases the annual Journal Citation Reports in late June. The JCR incorporates information from impact factors to assess the overall standing of its indexed journals. The company also suppresses impact factors for journals with abnormal citation behaviors.
Quaderi told us this change would not impact a researcher’s h-index, another metric that measures citation behavior and productivity. In other words, when Clarivate calculates h-index, it won’t remove retracted papers – or citations to those papers – from the calculation.
In 2011, Arturo Casadevall and Ferric Fang, who is now a member of our parent nonprofit’s board of directors, showed using the Retraction Index that journals with higher impact factors tended to have more retractions, for unclear reasons.
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On the point around incentivisation – Journals indexed in Web of Science Core Collection are subject to periodic re-evaluation and those that no longer meet our 24 quality criteria are delisted. A journal risks being delisted if they do not retract compromised content.
Our priority is to ensure that we provide the research community with trusted content. For us to consider an exception to our standard de-listing and/or embargo policies, publishers need to provide compelling evidence that all content of concern has been investigated, and appropriate editorial expressions of concern or retractions have been issued. Journals are not penalized for issuing retractions, which we recognize as a normal and necessary part of correcting the scholarly record, but we do need to reflect the current status of that published material, as citations to and from retracted content must be treated with caution.
RE: “A journal risks being delisted if they do not retract compromised content.”
For context: In 2024 Clarivate removed just 56 journals from the Master Journal List (MJL) for quality control reasons (“Editorial de-listing”). It accepted 591 new titles into the MJL in that time and the 2024 Journal Citation Reports (JCR) covers 21,848 journals.
It would appear that de-listing is quite infrequent and thus the “risk” a journal faces for being delisted is quite small.
I really welcome this change and hope other indexing systems follow suit. I am curious to understand the decision not to reflect this change in h-indexes though, as this is currency just as much as impact factors are – so I would imagine it could act as a deterrent for researchers tempted to engage in misconduct.