Can some versions of the WAIS III...

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...have a ceiling as low as the 91th percentile? I want to know... (Personnal reasons)

It depends, but it's possible. I don't know directly because your percentile depends not just on your score, but on the number of items on the subtest and the age you are when you take the test, which matters for children's tests.

A portion of the test with a small number of items, taken by a test-taker at the higher end of the test's age range, may conceivably hit a ceiling and be in the 91st percentile.

For the whole test, no, because if it were possible the test wouldn't be useful for distinguishing bright from gifted. But for a subscale, it's possible.

All of this assumes that the particular scoring method doesn't just assign 99 or 100 for any perfect score on a subscale.

The difference between the 91st percentile and hitting the ceiling of a test isn't all that significant; they both mean you are better than most of your peers, and by the 91st percentile, how much better doesn't matter all that much because other factors, like effort and concentration ability, will overshadow native talent in any real-world application of that skill.

Disclaimer: I have never taken a class on psychological evaluation.

Sorry I was meaning the WAIS *edited*

I've read that the ceiling for the Wechler tests (the version IIIs at least- the newest ones are structured differently) is in the 140s (the mid-140s would be the 99.9th percentile). 91st seems fairly low for a ceiling- I think that would only be in the 120s or so. I was given the WISC-III when I was 15 and scored a 147 for verbal IQ actually, though my performance IQ was much lower since I have NLD. That was the WISC however, and not the WAIS (the WISC is the version for children, which goes until age 16).

Are you asking because you received a score in the 91th percentile, and feel that it underestimates your intelligence? Don't forget that hitting the ceiling is not the only reason for not receiving a higher score. If you are fatigued, overwhelmed, anxious, not feeling well, etc., you may not perform at your full potential. Additionally, if you have autism, ADHD, or learning disabilities, your score may also be lower. Despite my high verbal IQ score, I score very poorly on some neuropsych tests because of my NLD and ADHD (inattentive-type). Even on a test of auditory word-learning, which I supposedly should be good at based on my overall verbal intelligence, I scored in the moderately impaired range thanks to stupid ADHD and difficulty with sustained attention to auditory information. If I'd been allowed to read the words instead of hearing them, I would have performed very differently. So please don't get hung up on any one score- IQ tests are not as accurate as they are made out to be, especially for those of us who are "neuro-diverse."

I did some reading online, and here is a description of how to recognize when someone has reached a test ceiling:

I stand by my original statement that after the 91st percentile, it really doesn't matter whether you hit a ceiling or whether you're simply at the 91st percentile; because once you're the best out of ten people at that particular task, chances are other factors are now much more important than raw talent.

Yeah, like Nobel prize winners.

The difference between someone with a 140 IQ and 170 IQ is like the difference between an aspie and an NT. The child with 170 IQ will have the same difficulties in a class full of 140 IQ that a 140 IQ child has in a class full of 100 IQ kids. And this is the problem with low ceilings on IQ tests. Ceilings do matter.