The debate about schools reopening is important given the potential economic benefits and public health risks at stake. So it's a shame that 3 bad applications of economics underpin the views of those most strongly in favour and strongly against reopening them.

Externalities: first, it's common for pro-openers to simply say "kids are at low risk from the virus." While it appears true kids are at v low risk of death and under-10s of transmission, overall they appear to catch and spread the virus. Remember the whole reason public health

interventions have been thought needed is because of the externality of spreading the disease, ultimately to those it could do severe damage to. The question then isn't whether kids are at risks themselves, but whether reopening changes networks to increase community transmission

Counterfactual: here, opponents of schools reopening talk as if the alternative is kids living in complete isolation. That's clearly not the case. Kids out of school might interact with *more* adults and vulnerable people day-to-day, particularly those cared for by

grandparents! So we shouldn't judge any single outbreak in schools (and there will be some) against a world of absence of the disease. Again, the relevant counterfactual is what would have happened to community transmission with kids out of school and a lot of parents wfh.

Ignoring the policy change: some supporters of reopening highlight evidence from Germany and some year groups returning to schools in the UK to claim more strongly that kids cannot easily transmit the disease at all. But these results likely reflect the policy of thin reopening!

Obviously, if you only send back limited numbers, there's much greater opportunity to spread students out, avoiding unnecessary contact. This doesn't tell us how the disease might spread in densely packed classrooms. There hve been big outbreaks in some US camps & Israeli schools

Might seem a fence-sitting conclusion, but people are lying if they say we know with any confidence what overall impact across-the-board school returns will have. Given it will simultaneously allow more parents to return to work, my hunch is that overall it will increase

transmission, possibly significantly. But the costs of keeping schools closed are huge too and the longer-run effects potentially more scarring. I feel sorry for politicians having to make this call. Because it is kids, the first major outbreaks are likely to have v high salience

A good contact tracing regime would of course provide excellent early information on where transmission is occurring and help solves these riddles quickly.