Yesterday,we posted on the retraction of a 2004 Nature paper on innate immunity whose findings had been questioned by two groups. A few hours after we posted that item, we heard back from the senior author of one of the papers doubting that data, Tom DeCoursey. DeCoursey makes a number of important points, so we thought it would be a good idea to share them as a post:
I was very happy to see that finally, after >6 years, the blemish of Ahluwalia et al (2004) has been erased from the literature. The retraction is extremely important to the field, for several reasons.
Despite the fact that a few insiders had doubts about the Ahluwalia et al (2004) paper from the outset, and this was discussed heatedly at numerous international (specialty) meetings, it is incorrect to assume that most people knew what the real story was. Very few people are expert enough, or confident enough, to evaluate opposing claims. Even after two groups (Femling et al, 2006; Essin et al, 2007) had published papers thoroughly disproving every major conclusion reached in the Nature paper, the stock position taken by authors who published papers subsequently was, “There is controversy in the field” or “Group A says this, but Groups B & C say the opposite.” It is not clear how many papers must pile up to refute one incorrect study. Certainly the number is greater when the original study was published in Nature or Science.
Because the literature is vast, anyone who searched PubMed could (until the retraction) come across the Ahluwalia study and fail to discover that subsequent work had thoroughly discredited its conclusions. In fact, several prominent reviews published as recently as in the past month, have cited the Ahluwalia et al study uncritically, because the authors simply were unaware of the subsequent work. The value of a formal retraction is that anyone who downloads the Ahluwalia study cannot fail to notice the word “RETRACTED” in red font at the top of each page.
In several instances (not all related to the present case), I have received letters from scientists who expressed their appreciation for papers we had published that refuted incorrect studies. In one case, a PhD candidate had intended to do his dissertation work based entirely on a published study that we had shown to be wrong (in this case, the error was scientific). The amount of time and resources that are wasted when, due to carelessness or fraud, a faulty study is published can be enormous.
More serious a problem than retractions are studies that are partially or completely wrong, but which are not retracted. Even if the results cannot be reproduced, it is very difficult to publish such a “negative result.” This means that other researchers will waste more time and resources, because they will have no way of learning that previous efforts have failed to replicate the faulty result. I discuss this problem here.
We have yet to hear back from Ahluwalia, who did not sign the retraction.