I am relived to announce that the psychologist we have been seeing since moving to this city is a normal, sensible human-being (as distinct from a teacher, for example). We had a talk today about our guy's unaccountably low score on his latest IQ test (down a full standard deviation from his previous one) and he suggested that we retest.
It's not that I am hung up on IQ, but we want to have numbers for the school that reflect what he can do. Schools tend to extract work out of kids that meets what they perceive to be their potential. If the school found out that our guy was producing work that exceeded his potential as measured by an IQ test, they would be sure to offer him less difficult things to do, so as to match that potential.
The other thing is that, if his conventionally measured IQ really were as low as the last measurement (borderline MR) then we would have to find out what processing facility he relies on for the competences he has. I'm talking about things like finding and installing DDR (Dance Dance Revolution) editing software and using it to make custom DDR tracks for his favorite songs, or finding the locations of all the DDR machines within a 20 mile radius so that he go visit the ones with the best songs. If I managed to that, I'd be feeling fairly proud of myself. If an 11-year-old is doing it without any help from grownups, there must be some cognitive capacity that he is using to do it. If it turns out that is is not the sort of cognitive capacity that can be measured by an IQ test then, we better find out what it is based on so that we can strengthen whatever it is.