Cops should do the same test. There was an NPR story a while back about a school, mostly black, that did poorly on a standardized test. The school officials declared the test racist. The science teacher couldn’t find that from the test. He wondered about lead. Low and behold the school was full of lead poisoned children. They started treatment and the scores improved by the end of the year ( the also abated the houses with grant money).

We know lead causes aggression issues. We know poor communities have higher incidence of lead in their homes. How many criminals could be prevented, or reformed with lead treatment?