Gifted Issues Discussion homepage Forums Identification, Testing & Assessment Differences in Stanford Binet and WISC ?

I am curious if anyone else has had wildly different scores on these two tests? DD had a GAI of 146 on the WISC-4 (VIQ=149 and PRI=136) and then received A 160 on all sections of the Stanford Binet 5. We had her tested privately with the WISC and the school system would not accept outside testing so they administered the Stanford Binet. Any idea what is different about these two tests? Thanks for any imput, the tester did not seem to know what could have happened. Other than perhaps some of the WISC is timed and the SB is not?

My children haven't taken the SB-5, so I don't have any experience with it, but I suspect there are multiple reasons you might see such a difference. Timed vs untimed isn't a large factor here, because you've taken the timed processing speed subtest scores out of the WISC when you are only looking at GAI. Do you have your dd's WISC subtest scores? It might be interesting to know what her FSIQ was and how her WM vs PSI scores varied. If I remember correctly, there's at most only one other timed subtest on the WISC.

The two tests are different, and I've always heard that the SB-5 is a better test for students who are (I think - I could be remembering this incorrectly) - stronger in non-verbal and visual-spatial etc areas.

It's possible you're seeing ceiling issues on the WISC - do you know if extended norms were used in the calculations? Did your dd have 18s and 19s for subtest scores? I think the SB-5 doesn't have the same ceiling issues. I know that when our EG ds was tested by our school, they preferred to use WJ-III Cognitive scores than WISC and one of the reasons was ceilings on the WISC possibly underestimating IQ.

As a mathematician, I suspect you also may be running up into territory where simply because your dd is at the upper end of the bell curve the curves don't fit well and perhaps we really just don't have the data to be able to say that score X on the WISC is equivalent to score Y on the SB-5 when you are up above the 99.9th percentile.

Last but not least, even scores on the same test can vary. My EG ds has taken the WISC twice, same tester, three years apart, and his scores on VIQ vs PRI totally flip-flopped in magnitude between those two tests. His overall GAI came out about the same value each time... because it was an "even" flip-flop. But why did they flip? Was it the amount of sun coming through the window on test day? Difference in performance for different ages in the norm group? The inflection in the tester's voice tone? I am fairly confident that his abilities have stayed similar through the years and he didn't all of a sudden morph from a verbal kid to a mathy kid or whatever... I think it's more a case of understanding the scores aren't exact, they have error bars around them.

So that's my 2 cents, fwiw!

Best wishes,

polarbear

Yes. I believe this can be a factor My son had the opposite - he did better on the wisc and he is much more gifted verbally and pretty weak in in non-verbal and visual-spatial areas. I prefer the wisc because a GAI can be calculated. Do you know what the WISC GAI was?

Oh sorry I just realized it was the GAI that was calculated on the WISC. I see.

The block design in the PRI is still timed, so speed can still have an impact. Tester rapport can have an impact. But all that said both my older girls had very stable verbal scores on both wechsler and SB tests, but tested at least half an SD higher on non verbal in the SB, it just seemed suit them better. Likewise the working memory.

Thanks for the input. I do know on the PRI of the WISC that she got all of the answers on block design correct but timed out of some of them. So I think her spatial skills may be stronger than the test showed due to the timing issue. She also got all of the answers on comprehension and similarities correct but no one has said anything about extended norms. She got all of the items correct on matrix reasoning but had an average score on picture concepts. She is not very fast. Her WM score was a 146 but processing speed was a 107, they only reported the GAI not the full IQ for the WAIS. I have always considered her more verbal than mathy but she does not have any issues with spatial things she just does not seem to enjoy them as much. The scores shocked us a bit, other than being mature she does not seem terribly gifted. She was complaining about school being tedious so we had the eval done to look for ADHD. The evaluator did say that she had absolutely no signs of ADHD, that she was probably just finding ways to keep herself busy in class.

Also, can you tell me what the EG etc.. means? Sorry, not trying to be dumb just not sure. My understanding was that anything over 130 was gifted, I was not aware there were differences. Any info is appreciated, thanks!

Sally EG generally means "exceptionally gifted". And yes there are levels of giftedness. 160 is as different from 130 as 130 is different from 100... Your child is very gifted by either measure you've used.

Here is a purely cynical question. Suppose we have a kid that is highly mathy, visual-spatial, stronger in non-verbal and weaker in verbal/comprehension/social/etcetera. Suppose we want to produce an IQ for some selective cutoff.

Is SB-V better for this goal than WISC-IV?

Thanks for the info. I googled the extended norms for the WISC and used the raw scores (I have the front page of the test it was stapled to the report) and it raised her GAI by 9 points, so the WISC GAI with extended norms is 155 , so more consistent with the other scores. 22B I do not know the answer to that one, maybe someone else will chime in. However, if different tests measure different things it does make since that someone would want a test that played to their child's strength. It's not like your teaching your child a test ahead of time and apparently they are both widely used. DD said she thought the SB was more fun, whatever that means.