School Closure vs. Restaurant Closure: Which Is Most Effective?

I’ve been asking for a while about the effect of specific COVID-19 countermeasures, and a new study in Health Affairs finally delivers. This is the first study of this type that I’ve seen, and it should naturally be taken as tentative until we see what other teams come up with. But with that said, here are the results:
The error bars in this chart are large, but the point estimates suggest that school closures and bans on large gatherings have no effect on reducing the spread of the virus. In both cases the effect is statistically insignificant, and in the case of school closures the effect is most likely to increase the spread of the virus.
Conversely, closing restaurants and issuing shelter-in-place orders both had statistically significant effects and both slowed the spread of the virus considerably.
There are, of course, several things that the study didn’t test. The most important is probably mask wearing. “Future work,” the authors say, “should also examine the impacts of other social distancing policies such as closing public parks and beaches, the requirement to wear masks in public, restrictions on visitors in nursing homes, state announcements of first cases or fatalities, and federal government actions such as prohibiting international travel.”
I’ll caution once again not to take these results as definitive yet, but further research along these lines is critical. If follow-up studies confirm the results on school closures, for example, it means we can send kids back to school in September. That would be a huge benefit for everyone.