Do you have any sources that can quantify what 6 IQ points is for the average person? Is it a percent benefit (does it benefit someone who would have had a 90 IQ more than someone who would have had a 130 anyway) or absolute benefit (you can quantify an IQ point the same for everyone).
I imagine it's the former, but I'm wondering if you have any other IQ-related sources.
Also, lead lowers IQ. Various estimates have been in the several point range, but at least one researcher has estimated an increase of 6 IQ points as a result of the lead ban: http://www.nytimes.com/2012/12/13/opinion/kristof-its-a-smar....