top of page

Is the CDC Faulty Mask Study the Reason for the Mask Mandates in Boise Schools?

Updated: Dec 18, 2021

In short, Boise Schools District receives most of their guidance (or reason to mandate) from Central District Health here in Idaho. CDH sources a CDC mask study on why they recommend masks in schools (not mandate). As we all know, the CDC doesn't always publish the most reliable studies and when you dig deeper, they are nearly always littered with holes.

Kinda like our kids masks in schools.

Here's the Mask study from the CDC and how they present the data in a pro-mask favor. It's called the "520 county study". Sounds impressive right? Well, let's go over it, shall we?

Do you remember our AZ study post that CDH referenced to support adopting the CDC's recommendations? Here's a brief run-down of the issues with the second study that CDH is using to justify adopting the updated CDC guidance from late-July (spoiler alert, some of the issues are the same). The second study CDC released to support its guidance is known as the "520 counties study". This study followed 520 counties across the country and compared pediatric COVID cases between counties whose schools had mandatory masking to counties whose schools did not. Counties with mixed school COVID masking requirements (such as Ada County currently since West Ada no longer requires masks and Boise does) were not included. The study concluded "The average change ... was 18.53 cases per 100,000 per day lower than the average change for counties without school mask requirements." 16.32 cases per 100,000 children for counties with school mask requirements vs. 34.85 per 100,000 per day for counties without school mask requirements.

Again, sounds like a pretty compelling argument for universal, required masking.

Here are a few drawbacks to the study, there are likely more.

  • First, the study was published on 10/1/21... two months AFTER the updated CDC/CDH school guidance was released implying that the 520 counties were selected because their data supported a pre-determined conclusion. Presumably the CDC (or anyone else) could choose a similar-size combination of the country's over 3,000 counties that would yield inconclusive or opposite results.

  • Second, the study was not a controlled study and didn't account for other factors such as, but not limited to, percentage of the population who had been vaccinated or already had natural immunity, differences in ventilation or time spent outdoors. Depending on the variation in the geographical location of the 520 counties, the schools in some counties could have had very little outdoor time due to extreme heat and other counties could have had a great deal of outdoor time or open doors/windows due to more mild weather.

  • Third, while the change in case rate for the counties whose schools did not require masks was more than double the change for the counties whose schools did, the impact due to this change varies widely depending on the case rate at the time. For example, if a county has only 20 cases/100k/day, an increase in 18 cases/100k/day is huge and nearly doubles the number of cases for that county every day. If however, a county has 500 cases/100k/day the difference is only about 3.5%. Is a difference of 3.5% of pediatric infections (the VAST majority of which are mild and for which elderly and vulnerable adults can be vaccinated) worth the removal of parental authority (individual authority for staff) and all of the side-effects of masking, particularly for children?

  • Fourth, the studies do not differentiate between community transmission rates or if transmission is increasing, decreasing or relatively steady. In fact, the Figure at the end of the study shows that pediatric transmission was already higher in the non-mask-mandated counties prior to the start of school so the difference could be due to community transmission that is unrelated to school operation.

  • Fifth, the study follows county-wide pediatric cases so it does not account for whether transmission occurred at school or not.

  • Sixth, and perhaps most important, the study specifically states its limitations. They are:

  1. causation cannot be inferred.

  2. pediatric COVID-19 case counts and rates included all cases in children and adolescents aged <18 years;

  3. county-level teacher vaccination rate and school testing data were not controlled for in the analyses

  4. the findings might not be generalizable

Did you catch the first and last items? "Causation cannot be inferred" and "the findings might not be generalizable". What does that mean?

  1. "Causation cannot be inferred" means that, just because the lower pediatric infection rate changes occurred in counties with schools that required masks, that doesn't mean that the mask requirement was responsible for the lower change in infection rates.

  2. "Findings might not be generalizable" means these findings may not be used to support universal conclusions.

So, by using this study as a basis to recommend universal, required masking, they are specifically going against two of the four stated limitations.

They are assuming correlation = causation and that the findings ARE generalizable. Again, we ask, Central District Health... is this the best you can do to justify required masking? Boise School District, do you really take recommendations based on such weak evidence seriously?

Are the many short and long-term consequences of mandatory masking and over-the-top quarantine policy worth the potential benefit, especially since 164/167 school districts around the state are able to keep their kids in school without these protocols?


Let the Boise Schools District know that you want Masks Optional.

Remember, being polite is the best way to treat people.

The Board


Sign the masks optional petition and see our video on our website.

Contact CDH and ask them why they base their recommendations for school masking on a flimsy CDC study.

The Board


Recent Posts

See All


bottom of page