There’s another problem with the two community-spread metrics selected — cases per 100,000 people in the last seven days, and the percentage of covid-19 tests that are positive. The first metric is entirely dependent on how much a community is testing; the second is flawed because it cannot be interpreted without understanding who is being targeted for testing.

The thresholds for these metrics are also very low. Communities only get into the blue zone if they report about one daily case per 100,000. Good luck to any districts hoping to get to that level before most people are vaccinated. And when a district eventually does move into the blue or yellow zone, the CDC wrote that this should be “documented continuously for several weeks” before transitioning to full in-person teaching, further adding delay to any potential reopening.

Remarkably, even if schools implement screening testing — defined as testing teachers at least weekly and offering a few different student testing strategies — the CDC still recommends hybrid models for schools in red- and orange-level communities. So if such a school did take on screening testing, all that would get them is moving middle and high schools into a hybrid model. That’s a big lift for not much gain toward reopening.