However, please let's not turn this into yet another "is IQ genetic" thread! I wrote my OP in terms of achievement, not intelligence, deliberately. It would be theoretically possible that what IQ tests measure could be completely unaffected by education or other environmental factors, and yet, achievement could be strongly affected by them. (Of course, it's unlikely to be so extreme: the obvious guess would be that both are somewhat affected, but achievement is more affected than IQ, perhaps much more.)
Ah, my apologies, I believe that I somewhat misread what you were asking/discussing. I guess that I was looking at it more from the standpoint of whether one could permanently lower potential or ability by improperly placing a child academically, which is a fear for me in dealing with my 2e child.
