From experience with my 2e son...his first IQ test had full scale IQ as 91 and then 3 years later (after ABA, etc. therapies) was 148. So I say, yes 2e-ness does affect IQ! But the psychologist wrote on the first test the standard statement saying something like "this is a correct and true demonstration of IQ and will expect to vary by 3 points," or whatever they put at the end of the test. But I haven't heard of anyone else who has had such a dramatic difference. Who knows?! Nan
My son's first FSIQ was 99 (and it was reportable, I'm pretty sure; the GAI wasn't much higher). His most recent GAI (because his FSIQ was not reportable) was 140. I believe that is "true" IQ is somewhere around 150, with the understanding that there are deficits in the areas of processing speed and working memory, because that is where his brother is and his abilities are fairly consistent with his brother's when you remove the 2E overlay.
Of course, back when all I had to go on was a FSIQ of 99, I thought I was totally crazy to think he was gifted at all. I really questioned myself for several years.
