Thanks all. I asked the tester the LOG question and he gave an excellent response, essentially:
While the SB5 and WISC-IV differ slightly, they are both standardised tests with the same mean (100) and standard deviation (15). There is considerable overlap in what the tests measure (e.g., verbal skills, visual processing skills, abstract reasoning, general knowledge, working memory, etc), with the main differences being that the SB5 also measures
mathematical ability and the WISC-IV also measures processing speed. In xx's case, I believe you can be confident that his overall level of ability (99.5th percentile) as measured by the SB5 would be similar to that obtained using other tests the school is familiar with (one might even argue that he would have scored higher on the WISC-IV considering QR was his weakest factor).
In terms of "levels of giftedness", many of the terms used (e.g., moderately, highly, exceptionally) are defined quite arbitrarily and are out-dated. It is much better to focus on percentile ranks and confidence intervals (and this is recommended by the Australian Psychological Society) because it doesn't matter what "label" you give xx's level of intellectual ability, the fact remains that he was performing overall better than 99% of age peers in four out of the five cognitive factors -he is intellectually gifted by any definition and needs intervention by way of enrichment, extension and possibly acceleration.
