Two of my DDs have taken both the WISC and the COGAT. For one, the COGAT was higher than the WISC and for the other, the WISC was higher, although both tested into our GT program based on COGAT. (Our system does not accept outside testing.)
Where having the COGAT helped was in flagging my oldest DD's fine motor skill/dysgraphia issues, which showed up on her Quantitative score. Had it not been for her COGAT, I'm not sure I would have ever begun to question that there was anything going on of a 2E nature.
