18 | Beware of Zombie Papers

Here’s a scary scenario: a journal editor issues a warning about your recently published paper because a retracted paper was inadvertently cited without noting the retraction. Papers that have been retracted but continue to be cited in the literature as valid work are known as zombie papers, and citations to zombie papers are frighteningly routine.^[1] Even scarier are the possibilities that your paper could get tagged with an expression of concern from a journal editor for a wrongful citation or that someone could make medical decisions hinging on the flawed science. Hence, take care to avoid citing a zombie paper.

First, know that not all journals screen reference lists within papers in press for retracted paper citations. Thus, even though this practice is becoming more commonplace among publishers thanks to a recommendation issued by the International Committee of Medical Journal Editors (ICMJE), do not rely on a journal-initiated screen to protect the integrity of your paper. Instead, you or an associate should cross-check each reference cited in a paper against the online abstract at the publisher’s website where retraction notices are posted. It’s important to use the publisher’s website because retractions are not always noted in popular databases like Google Scholar. While recent retraction notices can be found reliably in PubMed, use caution with older papers.

Second, if you do find a retracted paper in your preprint’s references section, don’t panic. Carefully consider whether excluding this paper will alter the conclusions. If not, simply remove it from the references. However, if the paper helped to inform the research in a substantial way, you will need to redo the analyses and possibly even some of the experiments. This prospect may make your blood run cold, but it is the responsible thing to do.

Third, if a reference to a retracted paper must be included, cite the retraction notice and not the original paper. Explanatory text will likely be needed to justify the decision to use this strategy. One possible reason to cite a retracted paper is when the uncertainty created in the wake of the retraction needs to be discussed directly.^[2]

The above steps will help you to steer clear of any scientific horror stories. Share this newfound knowledge about zombie papers with colleagues. We can all help to fight this scourge.