apm, yes. It looks like CoastalMom's DD did have a reading comprehension item set administered out-of-level, as she was probably on the kindergarten norms, to begin with, and shouldn't have had rc. Although at age six, one could place her on the first grade norms, and derive grade-based standard scores.
CM, I asked about when your children had the WISC because that might account for some of the difference in GAI. Your children were compared to children who were age 6 in 2002 (when the norms were gathered), which is 10 years from your first DC, and 12 years from your second DC. The Flynn effect says that scores rise with distance from the norm group (about 3 pts every 10 years for the general public in the USA, but with some research suggesting a steeper rate for the gifted population). (Conversely, previously-identified gifted sometimes have a noticeable drop in measured IQ on switching to current norms (say, if you retested your DD in the next year, on the WISC-V).) A two year difference in distance from the norms is probably not responsible for a significant part of their GAI difference.
