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Posted By: lovemykids Help Me Calculate the GAI for WISC-IV - 04/04/11 12:07 AM
Help! My DS took the WISC-IV. Because of variations between his indexes, the psychologist thought that GAI would best represnt my DS abilities. Unfortunately, I am not sure that she calculated the GAI correctly based on what I am reading on-line in the WISC-IV Technical Report #4.

Can someone please help me determine what his GAI score would be?

His verbal comprehension scaled scores were as follows:
Similiarities - 14
Vocabulary - 11
Comprehension - 15
(Information) - 12
VCI Sum of Scaled Scores - 41

His perceptual reasoning scaled scores were as follows:
Block Design - 16
Picture Concepts - 15
Matrix Reasoning - 19
Perceptual Reasoning Sum of Scaled Scores - 50

I calculated a sum of scaled scores of 91 which translates to a GAI of 138 per technical report #4. However, the psychologiest has calculated a GAI of 134. A GAI of 134 is not even listed in the table in Technical Report #4.

I tried to politely ask the psychologist about this because initial the report listed two different GAI scores - a 134 and 135. I even referenced the Technical Report #4, but she said that the 134 is correct.

Please help...I spent a lot of money on getting the WISC-IV test done and I want to make sure that the report is accurate. I also want to make sure that the county takes the psychologist report seriously and feel like they wouldn't if there is glaring error in the report.

Thanks!
Posted By: lovemykids Re: Help Me Calculate the GAI for WISC-IV - 04/04/11 01:26 AM
Thanks Dottie and thanks for remembering my other post. We finally got the updated report, which is what I am questioning.

His other test scores were as follows:

WMI - Sum of scaled scores 24 and composite score 110
PSI - Sum of scaled scores 23 and composite score 109.

So in my opinion there is a significant and unusual discrepany between the WMI and VCI, as well as between the PRI and PSI. However, to your point, I'm not sure what is considered significant and unusual. My DS was 6 yrs 7 mos at the time of the test if that helps.

The psychologist reason for the using the GAI in the report is because the "variation in the Indexes that compose the FSIQ is greater than 1.5 standard deviations, the FSIQ is considered uninterpretable". She cites that the "standard score difference between the VCI and PRI is less than 23 points; therefore the GAI may be used as a reliable and valid measurement of his current global intellectual ability."
Posted By: lovemykids Re: Help Me Calculate the GAI for WISC-IV - 04/04/11 01:32 AM
Another thought...Could the psychologist be thinking/calculating results using an older method of the WISC? Her report states she used the WISC-IV though.
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