I too wonder about this. It seems like all the kids they used to norm the test likely didn't have a tester that was familiar with whatever their specific needs were. It does make me wonder if seeking a gifted tester inflates scores compared to the norm sample. I mean, yes, everyone should have an ideal tester--but does everyone get that?
Beyond that I was surprised as just how subjective the scoring of some parts of the test were. I was told that an experienced gifted tester would better understand how to best pace the test for a gifted child and when to ask for more info if their answer were more oblique. But I do wonder if this isn't done for every child--it does seem to skew the results.
I was also told testers might feel "threatened" by a child so much brighter than themselves--and it might negatively bias it. But I think any good physiologist who can honestly treat everyone equal should be able to get acceptable results. The part where I do think it matters is that gifted psychologists are going to be in a much better position to interpret results. If they don't even know that extended norms exist you might not get as much info out of the test as you would otherwise.
In the end we went for someone experienced with gifted. I'm really curious though how the results would stack up if we tested again with someone else.
