I defer to other who know more about how this *really* works,
Well, I can't claim to be sure of how this *really* works any more than anyone else who has read about IQ testing, but I'll still give my opinion...
but the notes I took said this: in some PRI subtests, you get bonus points for speed. If PSI is slow, you shouldn't be able to do block design well. If PRI is high and PSI low, you need to worry about why the kid couldn't do the tasks on the PSI because the kid was fast in some things and it wasn't just about speed. He said good PRI scores rule out real speed issues and visual deficits.
I'm still not convinced. What about the kid with fine motor slowness who struggles with writing quickly with a pencil? He may whip through block design but struggle with coding. Only the PSI tests would tap into speed with using a pencil. Again with the visual acuity thing - I could do block design with my glasses off but wouldn't be able to do Symbol Search. My good PRI would not tap into the fact that I need my glasses.
