null Location Matters | Updates to Calculator for Organizations Help Make K-12 Schools Safer

The WTT Calculator for Organizations has two new inputs that make its COVID-19 testing recommendations even more personalized for your school (or workplace): The number of people participating in your testing program and your location. Check it out!

November 29, 2021

We're about a quarter of the way through the school year (or a third of the way, depending on where you live). Kids ages 5 – 11 can now get vaccinated (yay!). Wasn’t the COVID-19 experience supposed to be easier by now?

Unfortunately, with case counts rising in some areas and falling in others, and guidance regarding masking, distancing, contact tracing, and testing varying from place to place, it can be harder than ever to know how best to keep your K-12 school as safe as possible for in-person learning. The When To Test Calculator for Organizations can help – now with two new functionalities that make this tool even more useful in the school setting than before. 

People Being Tested

While we all wish that everyone in our schools would sign up for COVID-19 screening, that rarely happens (the exceptions are districts such as Baltimore City Schools, where testing is required for in-person learning). 

Thanks to a recent upgrade, the results you receive from the When To Test Calculator for Organizations now take your level of testing participation into account. When you start the Calculator, your first input includes not just the total number of people in your school – it also asks you for the number of people who will be participating in your testing program (green box below). Don’t worry if you don’t have exact numbers at your fingertips. If you’re not sure, you can estimate the percentage of your population that you think will be participating.


As it has throughout the pandemic, the level of COVID-19 transmission in the community continues to vary greatly from place to place. Since the level of COVID-19 in a school reflects the level of disease in the community around it, knowing the “COVID weather” in your area is critical. 

The Calculator now looks up that information for you. All you have to do is enter the state and county in which your school is located (green box below); the Calculator then uses a sophisticated machine-learning model to estimate the true prevalence of COVID-19 in your area and plug that into its calculations. (Two exceptions: If your school is in a US territory or outside the US, you’ll still need to know whether you’re in a hotspot or not. But don’t worry – we’ve included links that will help you find that information easily.)

Keep Track of Your Testing Needs

Once you’ve input the number of people being tested, your location, and the four mitigation strategies we covered in our series, Four Steps to Fewer COVID-19 Outbreaks, the When To Test Calculator for Organizations will show you how frequently your school needs to screen for COVID-19 in order to reduce the chance of an outbreak. 

Case levels continue to change over time, which means your school’s need for testing will change, too. The data the Calculator uses to estimate the disease prevalence in your area is updated frequently, for exactly this reason. By periodically checking your results with the Calculator, you can make sure that the testing protocol you have in place is still adequate for your needs.  



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