WAIS-IV interpretation question... (2024)

awishingstar said:

So I'm well aware not to interpret FSIQ when Working Memory and Processing Speed are lower than VCI/PRI. What about when they're higher? VCI/PRI in the mid-60s, WMI/PRI in the high 70s/low 80s. FSIQ and GAI both fall in the high 60s with no significant difference between the two. I've got a stack of reference books to pour over on my desk tomorrow but thought I'd crowdsource in case one of you can point me in the right direction. Thanks!

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Don't interpret if indices difference is greater than 23pts. Same goes for gai: can't use if vci and pri difference is greater than 23. An index is not interpretable of subtest difference is greater than 5.

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Magick91683 said:

Don't interpret if indices difference is greater than 23pts. Same goes for gai: can't use if vci and pri difference is greater than 23. An index is not interpretable of subtest difference is greater than 5.

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Oh super, that gave me the google-fu needed. The greatest difference is 19 between indices and 3 within indices so all seems ok. Thanks so much.

awishingstar said:

Oh super, that gave me the google-fu needed. The greatest difference is 19 between indices and 3 within subtests so all seems ok. Thanks so much.

See Also

A Guide to the Wechsler Intelligence Scale for Children, Fifth Edition (WISC-V)

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Yup. Then fsiq is interpretable

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WisNeuro said:

This is where looking at the base rate differences may give some interpretive context. The base rates tend to be smaller with larger Index differences at the lower end of the IQ range. Also, few issues, interpretable vs. uninterpretable is highly dependent on the situation and if there was a cause of a drop in a certain area. We're kind of in the clinical utility vs academic discussion here. Which, brings us to another issue, FSIQ is probably the single most irrelevant number I can think of in most neuro evaluations. Unless you are trying to diagnose an LD or ID, it really has no use. I see only adults, so it becomes that much more irrelevant in my evals.

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Good point. Although fsiq is technically interpretable it's more helpful to talk about the strengths and weaknesses, not only between indices but even between subtests within an index.

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WisNeuro said:

This is where looking at the base rate differences may give some interpretive context. The base rates tend to be smaller with larger Index differences at the lower end of the IQ range. Also, few issues, interpretable vs. uninterpretable is highly dependent on the situation and if there was a cause of a drop in a certain area. We're kind of in the clinical utility vs academic discussion here. Which, brings us to another issue, FSIQ is probably the single most irrelevant number I can think of in most neuro evaluations. Unless you are trying to diagnose an LD or ID, it really has no use. I see only adults, so it becomes that much more irrelevant in my evals.

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Magick91683 said:

Good point. Although fsiq is technically interpretable it's more helpful to talk about the strengths and weaknesses, not only between indices but even between subtests within an index.

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Thanks both. This is an adult assessment for psychopathology and ID, so FSIQ is somewhat useful to have for that diagnosis. No notable cause for the discrepancy (no TBI; lifelong & consistent impairment; etc). Base rates for the larger index discrepancies range from 15-22%. Interestingly, despite 19 points between WMI and PRI, no subtest comes out as a significant "strength or weakness" based on the analysis. The only substantial difference between subtests is in the PSI, only 3 points different with symbol search better than coding. Otherwise performance was pretty consistent within indices - and apparently between subtests too.

awishingstar said:

Thanks both. This is an adult assessment for psychopathology and ID, so FSIQ is somewhat useful to have for that diagnosis. No notable cause for the discrepancy (no TBI; lifelong & consistent impairment; etc). Base rates for the larger index discrepancies range from 15-22%. Interestingly, despite 19 points between WMI and PRI, no subtest comes out as a significant "strength or weakness" based on the analysis. The only substantial difference between subtests is in the PSI, only 3 points different with symbol search better than coding. Otherwise performance was pretty consistent within indices - and apparently between subtests too.

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Adhd? Was processing speed also low?

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Magick91683 said:

Adhd? Was processing speed also low?

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There is no neuropsychological profile for ADHD.

Magick91683 said:

Adhd? Was processing speed also low?

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I'm not sure how or why this persists. There is scant often contradictory evidence for this, it not discriminatory (just as likely to have deficits as to not), and its not part of the DSM criteria.

erg923 said:

I'm not sure how or why this persists. There is scant often contradictory evidence for this, it not discriminatory (just as likely to have deficits as to not), and its not part of the DSM criteria.

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I tend to look more at working memory for adhd, In addition to other assessment measures and a really in depth clinical interview. I think the best way to diagnose adhd is a thorough look at educational history. I was personally just curious about processing speed.

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Magick91683 said:

Adhd? Was processing speed also low?

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Processing speed was relatively good (albeit normatively low). No evidence of ADHD from clinical interview!

smalltownpsych said:

The bigger the split between indexes, the less meaningful the global score for representing the true functioning. The other side of that would be to overinterpret small differences. From my perspective, it is crucial to make our interpretations based on the knowledge of the statistical properties of the measures such as base rates and also to examine other factors which I have often seen left out of the interpretation. Especially sociocultural since we are clear that this has an effect. I have seen where the FSIQ was reported as being meaningful with a 20 point VIQ/PIQ split in a person who spoke a foreign language up until the age of 14. The feedback was that they would not really be college material because the FSIQ was only 92.

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Even with a reliable IQ of 92, it'd still be inaccurate to say someone was not "college material" at that level. Whoever said that has a misunderstanding of the IQ literature. Plenty of low end of average people with college degrees out there. Heck, plenty of those people are getting masters degrees. And, if we updated the literature, I imagine plenty of people in that range with "doctorates" thanks to the proliferation of diploma mills.

WisNeuro said:

Even with a reliable IQ of 92, it'd still be inaccurate to say someone was not "college material" at that level. Whoever said that has a misunderstanding of the IQ literature. Plenty of low end of average people with college degrees out there. Heck, plenty of those people are getting masters degrees. And, if we updated the literature, I imagine plenty of people in that range with "doctorates" thanks to the proliferation of diploma mills.

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Agreed. I actually tried to clarify both points to the adoptive parent of the individual, but it was tough for them to get past the "lower than average IQ number (tried to correct that too) when I thought she was pretty bright". As this was someone I knew personally, I know that the kid did go to college and since they were in actuality "pretty bright", they did quite well. Last I heard she was deciding between veterinary school or law school like her adoptive parents had done.