Does reducing lead exposure limit crime?

These results seem a bit underwhelming, and furthermore there seems to be publication bias, this is all from a recent meta-study on lead and crime.  Here goes:

Does lead pollution increase crime? We perform the first meta-analysis of the effect of lead on crime by pooling 529 estimates from 24 studies. We find evidence of publication bias across a range of tests. This publication bias means that the effect of lead is overstated in the literature. We perform over 1 million meta-regression specifications, controlling for this bias, and conditioning on observable between-study heterogeneity. When we restrict our analysis to only high-quality studies that address endogeneity the estimated mean effect size is close to zero. When we use the full sample, the mean effect size is a partial correlation coefficient of 0.11, over ten times larger than the high-quality sample. We calculate a plausible elasticity range of 0.22-0.02 for the full sample and 0.03-0.00 for the high-quality sample. Back-ofenvelope calculations suggest that the fall in lead over recent decades is responsible for between 36%-0% of the fall in homicide in the US. Our results suggest lead does not explain the majority of the large fall in crime observed in some countries, and additional explanations are needed.

Here is one image from the paper:

The authors on the paper are Anthony Higney, Nick Hanley, and Mirko Moroa.  I have long been agnostic about the lead-crime hypothesis, simply because I never had the time to look into it, rather than for any particular substantive reason.  (I suppose I did have some worries that the time series and cross-national estimates seemed strongly at variance.)  I can report that my belief in it is weakening…