How about reading it using the link I provided, and considering it in the light of other studies cites in the original article and in the references section of this paper? I'm not claiming it to be the be-all and end-all of lead-specific social cost studies, but while we we discuss the reliability of the statistical conclusions large numbers of people are suffering the shitty first- and second-order effects of lead poisoning and society as a whole remains worse off because of a relatively fixable problem.