Of all the readings in the 2nd post, I found the ERIC article most useful. The IQ levels in Table 1 are interesting -- basically if you know nothing else about a kid other than they are reading before K, you should revise your estimate of their IQ from 100 to 130. I.e., there is big news in the fact that a kid is reading early.
One of the other things I took from it is that *conditional on IQ*, reading levels mean revert, but that this isn't true unconditionally. In other words, if you take 2 kids with 130 IQs, where one is reading at K and one is not, there will be some convergence in their reading ability. But if you compare an early reader with a 130 IQ with a typical non-early reader with an IQ of 100, the former kid will still be well ahead of the latter in a few years. This all seems very intuitive.
It is possible that this research result got garbled by the K-12 community.
