//The most important variable in reopening schools in this pandemic

The most important variable in reopening schools in this pandemic

Temperature checks are performed at Hollywood High School on August 13, 2020 in Hollywood, California. Due to Covid-19, combined online and classroom learning will become the norm for the coming school year. | Rodin Eckenroth/Getty Images

The Covid-19 cases popping up in schools around the US were entirely predictable.

Many schools across the US gambled on offering in-person classes in early August, even as their states were still battling uncontrolled spread of Covid-19.

In some of those schools, it hasn’t gone well.

In Georgia’s Cherokee County School District, for example, there have been at least 80 positive cases since August 3, and more than 1,100 students, teachers, and staff have had to quarantine. At the high school in Paulding County School District, which came to national attention after photos of halls crowded with mostly maskless students went viral, several students and staff