Gifted Issues Discussion homepage Forums Identification, Testing & Assessment More WISC questions

I can't answer all of your questions since I don't know the answers to all of them, but here's what I know:

1). Yes, GAI can be calculated in any circumstance. It doesn't matter whether the GAI subtests are high or low or whether there's a large discrepancy between GAI and full scale IQ. Yes, GAI combines VCI and PRI and leaves out working memory and processing speed. However, GAI would be substantially discrepant from full- scale IQ only if the GAI subtests are substantially higher (more likely) or substantially lower than working memory and processing speed.

2) I don't know much about extended scoring, sorry. But my guess would be, whenever a child attains either an 18 or a 19, whatever composite score (index score, GAI, full-scale IQ) that is dependent on that subtest(s) can be recalculated using extended scoring. I don't know, however, whether a particular school would take extended scoring seriously, though.

3) I guess it depends on the individual tester whether he would stop the subtest just because the child reached the ceiling subtest score although not all questions have been administered. I think, however, that most testers and definitely a good tester would only stop if the termination criteria were met or if all the subtest questions were administered and not stop just because the child already answered enough for a ceiling subtest score. Extended scores can be calculated only if you know the raw score for individual subtests. However, often, parents are not reported raw scores, only scaled subtest scores and composite scores.

4) I think here the answer is simple: the more information you get the better, so if there aren't money or time issues, it's good to ask the tester to administer all 15 subtests. WISC Arithmetic tests solving arithmetic word-problems and should be close to Numerical Reasoning (or whatever it's called, I am not very familiar with WJ-III). I think the two main differences between WISC Arithmetic and WJ Numerical Reasoning are that on WISC, you can't use paper and pencil and have to do all the calculations in your head. Also, WISC Arithmetic is timed, while Numerical Reasoning might be untimed (although I don't know for sure).