Separating out the confounding factors is definitely a big problem, but lots of effort has gone into just that. Drum has been following the Lead-Crime Hypothes

Separating out the confounding factors is definitely a big problem, but lots of effort has gone into just that. Drum has been following the Lead-Crime Hypothesis science since at least 2012. This blog post: https://www.motherjones.com/kevin-drum/2018/02/an-updated-lead-crime-roundup-for-2018/ https://www.motherjones.com/kevin-drum/2018/02/an-updated-le... provides an overview, but maybe not an ideal overview just because it's so long. Section 3 has links to some actual papers, and some of the other links may ultimately lead to papers, but there's so much of it that I didn't explore it deeply.