That CDC Study on Masking Children in Schools Just Got Blown to Bits

AP Photo/Susan Walsh, Pool

Remember that study the CDC commissioned and touted several months ago claiming to prove that masking in schools was highly effective and necessary to keep children “safe”? That study has now been blown to bits, and by none other than the “experts” themselves.

Per David Zweig, the study was so bad that it never should have been published in the first place.

This estimated effect of mask requirements—far bigger than others in the research literature—would become a crucial talking point in the weeks to come. On September 28, during a White House briefing, Walensky brought up the 3.5 multiplier again; then she tweeted it that afternoon. In mid-October, with the school year in full swing, Walensky brought up the same statistic one more time.

But the Arizona study at the center of the CDC’s back-to-school blitz turns out to have been profoundly misleading. “You can’t learn anything about the effects of school mask mandates from this study,” Jonathan Ketcham, a public-health economist at Arizona State University, told me. His view echoed the assessment of eight other experts who reviewed the research, and with whom I spoke for this article. Masks may well help prevent the spread of COVID, some of these experts told me, and there may well be contexts in which they should be required in schools. But the data being touted by the CDC—which showed a dramatic more-than-tripling of risk for unmasked students—ought to be excluded from this debate. The Arizona study’s lead authors stand by their work, and so does the CDC. But the critics were forthright in their harsh assessments. Noah Haber, an interdisciplinary scientist and a co-author of a systematic review of COVID-19 mitigation policies, called the research “so unreliable that it probably should not have been entered into the public discourse.”

Who could have possibly foreseen this? Well, for one, I did and can offer you this alternate headline: Bonchie Was Right.

When the study was first published in late September, I took a look at the claims and my spidey sense immediately went off. So much of what was being asserted seemed to be carefully crafted so as to give an impression that was misleading. Once I dove into the actual particulars of the study, I was less than shocked to learn that essentially everything the CDC was claiming wasn’t actually backed by the data.

So while the study’s lead author may “stand by their work,” that work provided no evidence for the CDC’s pronouncements about masks in schools.

Here’s what I wrote at the time to give you an idea of how flawed the study was.

In short, what we have is a “study” that didn’t even cover a period where children were in school — save for a week or so. The “study” is also based on a data set of counties that do not control for prior infection rates, testing capacity, etc. in order to conduct a valid comparison between areas that have school mask mandates and ones that don’t. And even still, they came up with a result that shows almost no difference in the real number of cases.

Lastly, just to put a fine point on all this, the CDC’s own study admits that it’s ecological and should not be used to assign causation in regards to masks and infection rates. They also admit a lack of control regarding several other key variables.

To recap, the CDC study picked a date range that was months long but only included a couple of weeks of children actually being in school. It then cherry-picked counties, some of which were already seeing rises prior to school being in session. They did nothing to control for differences in testing, and the actual statistical infection rate differences were minuscule. Finally, the study itself admitted that it should not be used to assign a correlation between mask-wearing and infection rates.

Still, the CDC rushed to push the study out on social media and in television interviews as proof that masking in schools was effective and needed. Members of the White House also repeated the claims and used the study as a way to snark at reporters who dared question why masks in schools were necessary. Given that dishonest blitz, why would trust anything the Biden administration says at this point? Especially when it comes to vaccines and masks?

In the end, we didn’t need to wait around for over two months for the “experts” to chime in on this study. It was apparent to anyone willing to do some basic research that it was absolute garbage. Yet, if you said that at the time, you ran the risk of being banned from social media. That perverse relationship between the supposed media gatekeepers and “the science” is incredibly damaging to public trust.