The Mystery of a Retracted Study That Came Back to Life
A new paper in the February issue of Pediatric Obesity probes an important question. Can a gardening, cooking, and nutrition program exert an effect on obesity risk for Latino youth? At first glance, the results are encouraging. Right there in the title, the authors answer the question. The LA Sprouts program “reduces obesity and metabolic risk.” But look a little closer and you’ll find a mystery. Is this a retracted study that has come back to life?
Back in May of 2015, the same four authors of the new study published a seemingly identical study in Obesity. It was an evaluation of the same program. The data in this study seem to be the same. Their conclusion was the same:
LA Sprouts was effective in reducing obesity and metabolic risk; however, additional larger and longer-term studies are warranted.
Seven months later, the authors and the journal editors agreed to retract this study from publication. The retraction notice explained that the data did not support the original conclusions:
The retraction has been agreed to because the statistical analysis was not correct given the cluster-randomized design, and the wrong degrees of freedom were used. The conclusion that the original paper drew about having demonstrated treatment efficacy was not supported in the corrected analysis.
In the new paper, you will find no explanation. No mention of a revised analysis that somehow justifies another twist in the story of this dataset. No reference to the retracted paper at all. All we have is a subtle suggestion in the new paper that the reader should be skeptical of these conclusions:
Because this was a small study of four schools, analysis of change measures between clusters of students in schools would be underpowered, and the current approach may lead to false positive results.
Retractions are an awkward, but important aspect of peer-reviewed science. Particularly in behavioral and biological sciences, fresh eyes can reveal flaws that escape the notice of researchers who are really close to a study. People pay close attention to retractions, because the truth matters in science. Honest mistakes account for most retractions. Finding and correcting honest mistakes marks a success for everyone, including the original researchers. All can take pride that peer-reviewed science is self-correcting.
So how did this retracted study come back to life in a new paper that’s very similar to the original one? That’s a mystery that remains to be solved.
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February 13, 2017