Thread by @Heritage

How reliable are government declarations that mask mandates prevent the spread of the coronavirus?

Our recent experience has left us less than confident that the public should trust the CDC’s published research—much less any pronouncements based on that research.

Our problem involves a paper that the CDC published in November.

The paper studies mask mandates in Kansas because, in July, Gov. Laura Kelly issued an optional mask mandate. Counties could decide whether to enforce the mandate or opt-out.

Many counties DID opt-out, but...

...the larger metropolitan areas did not.

Overall, 24 counties implemented a mask mandate, and 81 opted out.

The CDC paper argues that the mandates were a success.

In particular, the paper claims that “the increasing trend in COVID-19 incidence reversed” in the Kansas counties with mask mandates.

We noticed, however, that this conclusion is incorrect.

As our paper shows, the trend did NOT reverse in those counties.

Moreover, the growth in reported case incidence (and mortality) was, overall, virtually indistinguishable in counties with and without mask mandates.

It turns out that the CDC paper made an incorrect assertion because the authors used data that was later updated.

As statistical studies go, this sort of mistake is surely forgivable.

However, the CDC’s refusal to publicly acknowledge this incorrect assertion is inexcusable.

Note: We corresponded with the main author, as well as several editors and an Associate Director for Policy at the CDC.

There simply is no room in legitimate scientific study for refusal to admit mistakes.

Our experience, sadly, is not unique.

Even in those rare instances where government public health officials yield to scientific evidence and revise their recommendations, they seldom admit error.

On March 19, for example, the CDC abruptly changed its guidance for classrooms—saying desks need only be separated by three feet (rather than six).

The agency’s new “science brief” on the subject does not cite a single classroom-based study...

... that found desks should be kept six feet apart, but lists numerous studies supporting the one-meter (3.3 feet) standard long favored by WHO and the American Academy of Pediatrics.

The agency brief didn't cite a study posted earlier in March that found, based on review of numerous studies of classroom transmission, “no significant difference in student or staff case rates between schools with ≥3 versus ≥6 feet of distancing with a large sample size.”

The CDC changed its policy, but without acknowledging the damage its earlier recommendation inflicted on children, much less admitting error.

Unfortunately, throughout the pandemic, scientific facts have meant little.

While many facts were unknown when the disease first took hold in the United States, a great deal of the evidence was quite clear by May.

Read more: heritage.org/public-health/…