There was a nice natural experiment that happened a while ago where children with sufficiently high blood lead concentrations had the government perform lead ab

There was a nice natural experiment that happened a while ago where children with sufficiently high blood lead concentrations had the government perform lead abatements in their homes. And then see how much better the kids with the newly lead free homes do compared to the kids who were just a little too low lead to get these abatements but who were otherwise very similar.