I talked with a gifted progam coordinator in a public school who is supposed to be extremely experienced in gifted children. The program that she is in charge of is on top of the nation. I mentioned to her about a research paper done in 80s that describe the correlation between the group IQ test like Cogat and individual IQ test like WISC. The result is that the correlation between two only exists among the ordinary people. That makes sense for them to use Cogat in general population. However in the gifted population, the correlation starts to disappear. Furthermore, the negative correlation even shows up in about 30% of cases. This means that the higher IQ the lower Cogat. To my surprise she never heard of it. She said that all the students they selected for their district self-contained program based on Cogat score turn out to have high IQ. Therefore she believes that high Cogat equals to high IQ. Low Cogat equals low IQ.
