Thanks for the kind words and for shedding more light on the FSIQ, Aeh.
I had originally assumed that the FSIQ was derived from the five first level factors in their entirety and that some fancy extrapolation was involved in reducing the number of subtests involved in the score calculation, but knowing that it�s computed from only the core seven subtests clears a lot of things up.
In hindsight, I believe I meant to say that the FSIQ seemed like a weighted average of the GAI and CPI even though it�s based on more (and more unique) information, which in my mind seemed to contradict what happened when two subtests combined to form an index whose score is greater than the average of the two contributing subtest scores. Going from GAI and CPI to FSIQ seemed similar to what the expanded VCI did with the VCI: refining what�s already there versus changing the foundation.
Now knowing that the FSIQ takes bits and pieces from the other indices to form the most complete picture with a leaner amount of information, the weighted average makes more sense. It also agrees with how the WISC-IV has a more lenient average score cutoff for each FSIQ than the WISC-V, as that FSIQ is derived from ten subtests. Now I�m curious as to why the expanded scores don�t include an expanded FSIQ, unless adding the extra information would change the interpretation by changing the average (and sum) score thresholds.
Now for the real challenge: getting DS excited about more schoolwork (we promised to buy him a $60 game if he gave his best on the test, and now he is thoroughly engrossed in it)!
