There are a number of fields that seem to punch above their weight on Retraction Watch: Anesthesiology, home to the world record holder (and runner-up), and psychology, home to Diederik Stapel and others. But the red-hot field of stem cell research is another that makes frequent appearances, last year’s STAP controversy being particularly prominent.
There’s an interesting (but unfortunately paywalled) recent paper in Science and Engineering Ethics, “The Acid Test for Biological Science: STAP Cells, Trust, and Replication,” by Cheryl Lancaster, a small part of which tries to answer that question.
Lancaster applies the same methods Fang, Steen, and Casadevall used to broadly measure the causes of retractions in all life science and biomedicine to the specific field of stem cell research:
Using a very basic version of the methods in Fang, Steen, and Casadevall, PubMed was searched for all articles containing the term “stem cell” between 1973 (when Fang, Steen, and Casadevall report the first retraction) and May 2012 (when Fang, Steen, and Casadevall carried out their search); this resulted in 102,089 hits. When an additional search for retractions was added, this resulted in 62 hits; 0.06 % of papers referring to stem cells were therefore retracted between 1973 and mid-2012.
Fang et al found that roughly 4 out of 10 biomedical retractions stemmed from fraud; Lancaster spotted the same in stem cell research, specifically.
In the academic press then, stem cell fraud does not appear to occur with more frequency than in general bioscience.
The 0.06% figure is of course quite small, but it’s larger than the overall retraction rate — about 0.02%. But Lancaster’s numbers don’t, in fact, tell us whether fraud occurs at the same rate in stem cell research as in bioscience overall, since the fraud percentage only looks at retracted papers, rather than overall papers. In other words, the data tell us how often retractions in stem cell research occur because of fraud, but they don’t tell us how frequent such fraud is.
Since the author cited Ferric Fang, we asked him for his take.
Firstly, he noted that many papers — especially in a growing field such as stem cell research — have been published since 2012, so limiting the analysis to before that date would affect the data. He was kind enough to run the numbers himself, including more recent papers.
I have performed a quick search in PubMed and find that the first retracted article with the term ‘stem cell*’ was published in 1989 (PMID 2474759). I therefore limited my analysis to articles published between 1989 and the present. I found 14,761,843 journal articles, with 209,038 containing the search term ‘stem cell*’. A total of 3,244 articles (0.022%) published since 1989 have been retracted, 110 of which contain the search term ‘stem cell*’. This represents 0.053% of all articles containing the search term ‘stem cell*’ that were published since 1989, which is a 2.4-fold excess over what would have been predicted if the stem cell field were representative of journal articles as a whole. In other words, an average rate of retraction would have predicted 46 retracted articles containing the search term ‘stem cell*’, but the actual observed number is 110. This supports the assertion that retractions are more frequent in the stem cell field than in some other branches of research, although the proportion of retracted articles is still very low (about 1 out of every 1900 articles).
In reviewing the reasons for retraction, I had some difficulty finding the retraction notices for a few of the articles, but I can assign at least 56 to fraud/suspected fraud (51%). (By ‘fraud’, I mean data falsification or fabrication). This is slightly in excess of the 43.4% attributed to fraud/suspected fraud in our 2012 study.
So while the data are nuanced, there is some evidence that yes, retractions are more common in stem cell research, and they may be more commonly due to fraud. Whether fraud itself is more common, however, is unclear.
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