2 ms·

Yes, I guess you need 2 scatter plots; 2 years ago and now. (assuming population density is same in both)

• maxerickson 10y ago
  I think it is simpler than that. Baseline lead exposure is very low so absent a specific problem high density areas will still have few high test results, and the problems with accidentally making a density map aren't so prevalent when a small area is under consideration.
  • tyingq 10y ago
    In this case it was. But, water isn't the only way to get lead exposure. There were the novelty drinking glasses distributed by McDonald's for example. Or kids eating lead based paint flakes from the porches of older multi-tenant buildings. Basically just trying to say that there's value in having experts around versus thinking one type of methodology just always works. As I understand it, in this case, the water supply wasn't contaminated with lead. It was either more acid or more alkaline than it used to be, which caused the individual houses with lead pipes to leech more lead. That's a pretty specific causality where a scatter plot was the most useful approach.
    • maxerickson 10y ago
      Yeah, it was the interaction between the water and pipes. Here's the baseline data though: https://docs.google.com/spreadsheets/d/1driDoWu_lz1IHf1NHVFkc7MT3nr1G0luaoaCgTJSn5o/edit#gid=139983916 https://docs.google.com/spreadsheets/d/1driDoWu_lz1IHf1NHVFk... In most counties in Michigan, there are very few addresses with a child that has been tested and has high blood lead levels. So even a small cluster prompts further investigation.