I don't see in the article how they control for the IQ drop they think occurs (up to 5 points) being the same as the error margin for IQ tests (+/- 5 points).

I don't see in the article how they control for the IQ drop they think occurs (up to 5 points) being the same as the error margin for IQ tests (+/- 5 points). How does that work.. ? It's not like IQ tests are considered that reliable or unbiased. Also looking for studies.. they're observing the IQ drops in children who were exposed to excessive flouride beyond what's supposed to be in water. US levels all fall into the "low exposure" range in these studies.