Emily Oster, an economist at Brown University, has been studying transmission rates at schools that reopen and concludes that they are very low.

Writing in the Atlantic, she says that:

It’s now October. We are starting to get an evidence-based picture of how school reopenings and remote learning are going (those photos of hallways don’t count), and the evidence is pointing in one direction. Schools do not, in fact, appear to be a major spreader of COVID-19.

Since early last month, I’ve been working with a group of data scientists at the technology company Qualtrics, as well as with school-principal and superintendent associations, to collect data on COVID-19 in schools. (See more on that project here.) Our data on almost 200,000 kids in 47 states from the last two weeks of September revealed an infection rate of 0.13 percent among students and 0.24 percent among staff. That’s about 1.3 infections over two weeks in a school of 1,000 kids, or 2.2 infections over two weeks in a group of 1,000 staff. Even in high-risk areas of the country, the student rates were well under half a percent. (You can see all the data here.)

School-based data from other sources show similarly low rates. Texas reported 1,490 cases among students for the week ending on September 27, with 1,080,317 students estimated at school—a rate of about 0.14 percent. The staff rate was lower, about 0.10 percent.

These numbers are not zero, which for some people means the numbers are not good enough. But zero was never a realistic expectation. We know that children can get COVID-19, even if they do tend to have less serious cases. Even if there were nospread in schools, we’d see some cases, because students and teachers can contract the disease off campus. But the numbers are small—smaller than what many had forecasted.