Dude that is interesting and I understand the mathematical reasoning for what you are saying. How would you tell a child who did well on the test because they are truly that gifted from a anomaly.
My guess is you don't other than observation, time, or additional testing?
My son has traits like the early speech, started reading at 2, learned all the states and capitols by four which includes by shape of state, plus can map most of the world and now it's the solar system he has switched to.
However he seems to jump around from interest to interest. It's not like he is reading Les Miserables or calculating super advanced math problems in his head. He just seems to really get stuff and master it after a very short time.
So I am curious the accuracy of a score like his.
