An Elsevier journal has retracted a study on the placebo effect coauthored by a researcher known for extreme claims that have failed to withstand scrutiny. The move comes after critics said the researchers misunderstood “what a ‘treatment effect’ is.”
The study, published in the Journal of Clinical Epidemiology in December 2024, analyzed 30 clinical trials examining treatments for a total of five conditions. The authors concluded “the placebo-effect is the major driver of treatment effects in clinical trials that alone explains 69% of the variance.” It has been cited once, according to Clarivate’s Web of Science.
The last author of the study is Harald Walach, who may be familiar to readers of Retraction Watch. In one now-retracted paper, Walach and his coauthors claimed the COVID-19 vaccines killed two people for every three deaths they prevented. In a different, also retracted paper, Walach and colleagues claimed children’s masks trap carbon dioxide. (They later republished the article in a different journal.)
Walach lost two papers and a university post in 2021 and now holds affiliations with the Change Health Science Institute in Basel, Switzerland, and the Next Society Institute in Vilnius, Lithuania. This retraction brings his total to four.
As we wrote in May, Gideon Meyerowitz-Katz, a research fellow at the University of Wollongong in Australia known for sleuthing, told us the results of the placebo effect paper seemed to indicate “simply being in a clinical trial is the main component of healing.”
According to the undated retraction notice, the journal “did not find any evidence of deliberate attempts to mislead or any scientific misconduct on the part of the authors.” The “authors agreed that the title is misleading and the manuscript should have been more nuanced or measured,” the notice continues, indicating the researchers misrepresented a formula and included a retracted study in their analysis. Nevertheless, the authors “judge that none of these mistakes change the overall findings and conclusions.”
Stephen Rhodes, a researcher at University Hospitals Cleveland Medical Center, had criticized the study in a letter to the editor in February, citing a “number of errors that lead to some sweeping conclusions.” In the letter, Rhodes wrote those leaps “reflect a misunderstanding of what a ‘treatment effect’ is.” In a placebo-controlled trial, Rhodes observed, the measure can’t be “due to placebo.”
The editors of the JCE “do not agree with all the criticisms” critics conveyed, according to the notice.
Neither Walach nor the study’s first author, Stefan Schmidt, a professor at the University of Freiburg in Germany, responded to our requests for comment.
The notice also states the retraction “has raised important questions in respect of the editorial and peer review process for this manuscript, for which the Journal bears responsibility.” David Tovey, co-editor-in-chief of the JCE, told us “as a journal editor, I have to reflect on whether this situation could have been avoided.”
Like Retraction Watch? You can make a tax-deductible contribution to support our work, follow us on X or Bluesky, like us on Facebook, follow us on LinkedIn, add us to your RSS reader, or subscribe to our daily digest. If you find a retraction that’s not in our database, you can let us know here. For comments or feedback, email us at [email protected].