My sister once told me that her kids' school had said that early IQ tests are generally [/i]higher[i] (I think they said "inflated") than later results. I asked her for more information, but she didn't know anything more or the source, etc.

I have one DS who tested high on IQ test at age 5 (156), and now doesn't test startlingly well on SATs (which are supposed to correlate). I don't believe his IQ has decreased, but think that he's a slow reader (as am I).