Where I live, about half of kids qualify for the gifted program through private testing with the WISC--after scoring too low on the CogAt. However, there is much debate about the ethics of this (e.g. Is this fair to families with low to medium amounts of financial resources? Are certain private testers considered "good" by subsets of parents because they "help" children to score well? Is the gifted program best suited for kids who score well on the CogAt in comparison to the WISC?) Another thing to consider is that 140 is a pretty high bar. Your child can be considered gifted with a score of 130, but would not qualify for the program that you describe.
