That was what I was told (but spoken more eloquently by kccook:)) about the extended norms. I called Pearson, the company that creates the WISC-IV and there were only two children in the entire norming sample that had a GIA over 145 and no children that has a FSIQ over 145. So if your child scores in that range (or higher, which is the case for the children of many of the people on this board) they are not being compared to a large sample, they are being compared to two children. So for very gifted children it given them a larger sample to be compared against AND is more statistically sound. The intention was not to raise scores but to give the group (that already qualifies for DYS for the most part) a true comparison group.
