Why Controlled Trials and Masking in School Won’t Work Now

As the school year has progressed for the last 1-2 months, the topic of masks in school still remains a hot discussion.  We hear parents on both sides of the argument express their points for or against the use of masks in our kids.  There are also parents stuck in the middle, not sure where to turn to.  This is due to the lack of scientific journals or articles specifically targeting masks, kids, and schools.

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Randomized Controlled Trials

One of the biggest talking points AGAINST the use of mandatory masks in schools is the lack of randomized controlled trials.  These are considered more of the gold standard to data collection.  Now you may be asking “Dr Toffle, what is an RCT (randomized controlled trial)?  Why are they so important?”

The purpose of an RCT is to try to limit outside influences on a study so that one may be able to determine if an intervention is truly beneficial or not.  Let’s look at vaccines as an example.  In these studies, a person may be randomly chosen to receive a vaccine or placebo based on certain criteria, making sure that enough people from each age group, gender, race, etc are in both the study group (vaccinated) and control group (placebo).  This allows for the researchers to see if the intervention of a vaccine helps with the desired outcome of reducing the spread of specific diseases.  Typically in vaccine studies the participants are also “blinded,” meaning they don’t know if they received a vaccine or not.  In a study involving masks, it is kind of hard to blind someone to this type of thing.

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How Would an RCT Involving Masks and Schools Be Designed?

Essentially, you would take various schools in different school districts and randomly assign each one to utilize masks or not.  One would have to control based on school type (elementary, middle, high school), as well as mix up the use of masks within the same school district.  This would mean that an elementary school in District A may use masks, whereas the middle school in the same district would not.  This allows for the prevention of bias related to local infection rates in the community (to some extent).

You would then see how the number of COVID cases in kids spread through the schools via reporting.  You would have to decide on how to measure this, either through parental reporting, daily symptom logs, health department reporting of positive cases, or weekly testing in the school to assess for asymptomatic cases as well as symptomatic. 

One issue is you also have to decided WHAT intervention you are studying – is it the USE of masks or the MANDATING of the use of masks?  Confused?  If you want to know if masking works, you would have to have one school use all masks and another school not allowed to use any masks.  If you are studying the mandating of masks, then you are evaluating more the behavioral patterns in parents and students on the use of masks and inherently assuming masks are beneficial.  I think in most cases you would have to study the USE of masks first before you can study if MANDATES are beneficial. 

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Why Do I Think This Would Not Work?

Personal Bias

Sadly, in our world the use of masks has been so politicized that natural biases are already at play.  Since we CAN’T blind someone to the use of a mask, we know that these personal feelings would influence the study.   Let’s look at the following example for me to explain this more:

  • Imagine a school district gets assigned to always wear a mask.  There are parents out there who absolutely refuse to have their kids wear a mask.  In these situations, we have seen the same parents pull their kids out of school and home school to avoid the use of masks or change school districts.
  • On the other side of that, there are parents who adamantly want their kids to mask in school.  Imagine if their child were to be placed in a school selected NOT to wear masks?   We are still seeing the same situation where these parents are pulling their children from school and choosing to home school. 

In both of these scenarios we see how personal bias can influence the kids being used in the study.  However, it is not just pulling kids from school that is the issue.  This behavior may also carry out to the real world where these same families are less or more cautious on what they do in public, including social events, sports, travel, etc.  This may inherently cause a bias on case numbers within the community being studied which again can influence how many cases we see in school at any given moment.


I think the discussion on teacher intervention is also important.  Do you have all the teachers where a mask in the school no matter what, removing their influence on the cases?  Do you make sure all teachers have to be vaccinated?  Do you control by having them vaccinate AND mask no matter which school system they get placed in?  These are all variable one would need to look at to determine how to best study this scenario.


As we know, vaccines are only for those 12 years old and up at this moment.  This would potentially affect the study depending on vaccination rates within the school and community.  These vaccination rates also affect the personal decision some families will make based on child involvement in school, activities, or social events.  Again, this type of bias would need to be controlled across both study groups.

When to Stop a Study

Anytime a study is being performed, there needs to be safety measures in place that prevent the harm of the study participants.  In this scenario, how would you determine this?  When do you decide this measure has been met?  Do you need to see significant spread within a class?  The whole school?  What is that number?  Does the severity of disease in children influence this decision, or does the knowledge that they could spread the illness to others in the community take precedence?   These are all questions that need to be answered. 

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As mentioned above, the topic of masking has been a hot topic when it comes to our kids.  We do not have large controlled studies in schools with masks, but one also has to ask if it is ethical to perform such a study during a pandemic situation.  In my opinion, the benefits absolutely out-weigh the risks of wearing a mask at school (no I am not going to get into that argument at this time).   

In the future, once COVID is under control or at least no longer a significant threat to our country’s health, I think we can absolutely study this further.  We know influenza is spread easily through kids who tend to be spreaders of the virus.  One could randomly control masking in schools during the flu season and follow flu spread as well within these communities.  However, we are not at that point yet.  Last year we had no flu season.  This year, we still don’t know what to expect. 

We may end up with good data this school year based on what current schools are doing. For instance, here in Omaha, Nebraska, each school district is doing different things. Some have had mask mandates since school started. Others have it optional. Others have since mandated it based on cases in school. Seeing how cases within these schools occur may help us with some baseline data on masks and schools. However, each district is also reporting cases differently, so data collection may be difficult. This is obviously NOT a randomized control trial, but it may be the best thing we can get.

Imperfect Dad MD

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