Betty Crocker Fudge Brownies

Fudging Conclusions About Childhood Obesity Prevention

“We have a pretty good idea of how to curb childhood obesity.” Such convictions run deep. And because of those convictions, prevention is a frontline strategy for dealing with childhood obesity. So it’s especially dispiriting when we see the scientific literature stained by a paper fudging conclusions about childhood obesity prevention.

No Significant Effect Morphs into Some Evidence of Effectiveness

In the Australian and New Zealand Journal of Public Health, Mary Malakellis and colleagues published a new report last week on a large obesity prevention program. “It’s Your Move” is the name of the program.

Deep in the bowels of their paper, you will find that the sum of all their data showed no effect. But, the authors did not stop there. They picked apart the data to look for subgroups with an effect. They found it in two of the schools they studied.

So their abstract failed to mention finding no effectiveness in the overall results. And their conclusion claimed “some evidence of effectiveness.”

A Biostatistics Perspective

In matters of biostatistics and scientific rigor, we prefer to rely on deep expertise. So we asked an expert, Professor David Allison, about this study. He told us:

Despite the claims of effectiveness in the paper’s abstract, the body of the paper clearly describes the findings as null. The authors state “Models to Compare the Intervention and Comparison Groups (i.e. All Three Intervention Schools Combined Compared to All Three Comparison Schools Combined) …showed No Statistically Significant Interaction Effect on Weight, Height, BMI, BMI-z and Proportion of Overweight/obesity.” The contrary statements in the abstract are an inappropriate use of spin as defined by Boutron et al. They lead to distortion of the scientific record and propagation of myths and presumptions which are all too common in the obesity domain. Authors and journals should hold themselves to higher standards of accurate reporting.

We need prevention that works.

Null findings offer golden opportunities for learning. You do a study and the data tells you, you were wrong. That intervention – perhaps a wonderful prevention program – didn’t work the way you thought it would.

Maybe the study was flawed. Or maybe the intervention just doesn’t work. Perhaps we need a new approach. But if you ignore that null finding, you’re kidding yourself. You might deceive others. And you get in the way of progress.

That’s not good.

Click here for the study and here for perspective on the importance of negative findings.

Betty Crocker Fudge Brownies, 1970 advertising provided by Classic Film / flickr

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.


 

August 2, 2017

3 Responses to “Fudging Conclusions About Childhood Obesity Prevention”

  1. August 02, 2017 at 3:28 pm, Allen Browne said:

    Ted,

    You are tough – but you need to be. It’s good for the kids.

    Thank you!

    Allen

  2. August 08, 2017 at 5:18 pm, Paul Ernsberger said:

    Strict application of this rule would lead to the disappearance of the obesity trial literature, except perhaps in the Journal of Negative Results.

  3. August 09, 2017 at 3:58 am, Ted said:

    Thanks, Paul. The wisest rule would be to pay attention to unexpected outcomes, rather than paper over them.