Calculating GAI with sum of scaled scores

Posted by: League

Calculating GAI with sum of scaled scores - 05/13/22 04:29 PM

Hi, my child's psychologist did not provide a GAI for her, only an FSIQ, but I believe the GAI may turn out to be higher than the FSIQ. In adding up the scaled scores of the 5 subtests that contribute to the GAI, I get a total of 70 (Similarities 15, Vocab 18, BD 10, MR 12, FW 15 = 70 total)

Could anyone calculate what her GAI would be for me? I've already followed up with her tester twice to ask, but have yet to receive an answer.
Posted by: aeh

Re: Calculating GAI with sum of scaled scores - 05/14/22 03:06 PM

What makes you think the GAI will be significantly higher than the FSIQ, btw? In general, the default is to preference the FSIQ in interpretation, unless there are significant differences among the index scores, in which case one can have a discussion about additional interpretations (although from a technical psychometric standpoint, the FSIQ is still the most robust measure).

If you are looking for documentation of ability measures of 130+, the GAI will not provide that in this case. (If Digit Span and Coding are both at least a 9 or so--i.e., in the Average range--then the FSIQ is not significantly lower than the GAI.) From the scores you've provided, I suspect that the measure that you may find more informative to pursue would be the VECI, which requires two more verbal subtests. But whether it accomplishes your goals depends on your situation.
Posted by: League

Re: Calculating GAI with sum of scaled scores - 05/14/22 04:43 PM

Originally Posted By: aeh
What makes you think the GAI will be significantly higher than the FSIQ, btw?


aeh - I know the GAI won't be significantly higher, but maybe a mere few points more, which may get us the score we need (126+) for participation in our district's high cap program. Her VCI was already 136, so I could advocate for inclusion based on that, but they seem to really prefer either an FSIQ or GAI of over 126. Her FSIQ just missed the cut, at 122. Hopefully that makes more sense now.
Posted by: aeh

Re: Calculating GAI with sum of scaled scores - 05/14/22 06:31 PM

Ah. That does make more sense. In that case, yes, push your evaluator to produce an additional letter or amended report documenting the GAI.