Now, it is important to understand that all of this will give, at most, are statistics. My favorite example for this is that "men are in average higher than women" is a true statement inferred from statistics. I am taller than many men, and that doesn't contradict the statement, nor it disproves it. In the end, you can't predict anything for one particular individual.
I apologize for my grammar up there. Clearly my English had not woken up yet. I changed the sentence and ended up with an extra "are" and the "higher" instead of taller.
Somehow those studies both state that "within" 10 points of each other, and also that if there is one gifted the other one is likely to be. However, I can imagine many cases when those 10 points (even more so if it is >10) land the kids on both sides of the gifted/non-gifted line.
