Gifted Issues Discussion homepage Forums Identification, Testing & Assessment WPPSI III vs WIPSSI Iv vs WISC IV

My DD had the WISC-IV test done when she was 7. While my DS had a WPSSI-IV just done at 5 years. Can some done tell me if WPPSI scores are directly comparable to the WISC scores?

Also I have been told that the WPPSI-IV score come in significantly lower than the WPPSI-III scores. Does anyone have knowledge of this?

Thanks.

In theory WPPSI and WISC scores should be directly comparable and across any version, in reality it's probably more true that WISC and WPPSI versions that come out at the same time should be directly comparable but two versions of the same test taken by the same child on the same day could produce quite different results (ie yes the WPPSI iv would likely score lower than the WPPSI III).

Also, with the same test over time it seems likely that a 5 yr old doing any version of the WPPSI in it's last year before a new test is introduced will score higher than a similar 5yr old tested back in it's first year of use.

Although possibly my observations of patterns apply a more to gifted children and less to average children? Disclaimer: not an expert!

Nope, you are correct about editions, MumofThree. You are describing the practical implications of the Flynn effect.

The bigger difference is between the WPPSI and the WISC. The WPPSI-IV and the WISC-IV do not have the same index structure, nor do they have nearly as much overlap in subtests as, say the WISC-IV and WAIS-IV. The WPPSI-IV is more like the newly-released WISC-V.

I'll try to answer in more detail later.

Just to add the WISC was taken in 2013 while the WIPSSI was taken in 2014 (Roughly 1 year apart).

Yes well the child taking the WISC IV took it in its last year before replacement, the child taking the WPPSI IV took it in its first year...

AEH the thing I dont understand is that the flynn effect is described as a few points per decade isn't it? While each time a new test comes out the difference in scores at the gifted end seems to be more like a standard deviation...

Yes. The Flynn effect averaged out over the whole spectrum appears to be about 3 points per 10 years, and this seems to hold pretty well for the middle of the curve, but it appears to be greater at the top end of the curve (and some evidence suggests that it may be less at the bottom end of the curve). Since we don't really know why it occurs, or what the shift in standard scores represents at a functional level, it's still a bit difficult to explain or predict the changes. (I think I have speculated elsewhere on the forum some of the possible explanations, but we still don't REALLY know.)

Flynn effect should not impact test scores just a year apart. Should it? It comes more on the fundamental test design. I was specifically looking at these top level categories in WISC-IV and WIPSSI-IV:

Verbal
Perceptual
Full Scale
GAI

Are these scores directly comparable?

The Flynn effect does not affect scores only a year apart by much, when you are talking about the same instrument, but it affects this WISC-IV/WPPSI-IV discussion because, as was noted upthread, the WISC-IV administration occurred in 2013, when the norms were 10 years old (probably really 11, as the standardization data would have been collected many months, even up to a year, before the publication date), and in the last year before being superseded by the next edition (the WISC-V was released less than a month ago). The WPPSI-IV administration, OTOH, occurred in 2014, the year of its publication, when the norms were less than a year old.

The issue of the Flynn effect is more descriptively labeled as norm obsolescence, which clarifies that it is not when the tests are administered per se that affects their standard scores, but when in the lifespan of the norms they are administered.

And yes, it's the structures of the tests that are not one-to-one comparable, although attempts were made to make them so. The global/full scale score is probably the place with the closest match. The Verbal tasks are very similar, so one would expect a better relationship. The perceptual tasks are not exactly the same. Then, of course, is the question of what tasks best assess the theoretical cognitive processes at which developmental levels. It's possible that the same task may measure different skills at different points.

Most importantly, when comparing WPPSI and WISC scores of any kind, one is usually comparing very young children with school-age children. The younger child usually is expected to have a less-stable result. If you are measuring the same child on both instruments, this close together in time, then one of the administrations must have been done in the top of the WPPSI age range (test ceiling effects come into play for higher functioning students--not necessarily that high, either, just above average), and the other administration must have been done in the beginning of the WISC age range (now floor effects become a factor, except with fairly high functioning students).

So would that indicate a child tested for WPSSI should eventually be tested on a WISC like test for accurate identification?

If that kind of identification has value for you, then, yes. This is so not only because of the differences in structure, but even more because the WPPSI only goes up through age 7-7, long before IQ has really stabilized.