Gifted Issues Discussion homepage Forums Identification, Testing & Assessment how is FSIQ calculated

Can someone tell me how is Full Scale IQ calculated from the from the IQ scores of the subsets? i.e VC index, WM index et.c

Thank You.

You have to have a manual to look it up in a table. It is not an average of the other indices.

Do you have this table? Where can I get this table?

Thanks

You can get it here - for a minimum of $1069.

The FSIQ is determined by the sum of the scaled scores from the 10 subtests of the WISC (each subtest's scaled score can range from 1-19, higher if extended norms are used; the scaled scores are NOT the same as the composite scores that have a mean of 100). So, if you have the sum of scaled scores (or can calculate it if a tester provided the 10 subtest scaled scores) you may be able to figure out the FSIQ by looking for the same scaled score elsewhere on this board. Many people have posted WISC scores including both the sum of scaled scores and the corresponding FSIQ. So if you find a sum of scaled scores that matches yours, you have the FSIQ.


The following table won't be useful for 99.9% of the population, but the FSIQ equivalents using extended norms are available in the WISC Technical Report #7 (link below). Of course, these only apply to kids that needed the extended norms and have a sum of scaled scores greater than 167 (which corresponds to an FSIQ of 150 or higher), but just in case you are looking in that range, here is the link:

http://www.pearsonassessments.com/N...C-8E4A114F7E1F/0/WISCIV_TechReport_7.pdf

It's probably propietary/confidential, but may be deduced from many examples of posted scores.

Hmmm. I’ve been thinking about the conversion of the Sum of Scaled Scores to the FSIQ (I have nothing better to do while I sit around waiting for trick-or-treaters) and I am very surprised I can’t find this information online. Granted I am a statistician, but it didn’t take me long to figure out how one would statistically calculate an FSIQ from the Sum of Scaled Scores. I would think this calculation would be available online somewhere. Is it really possible for this information to be proprietary?

I also don’t know why a psychologist would keep the FSIQ out of a WISC report. I personally think it should be included, even if the GAI is a better indication of an individual’s giftedness (although this should be mentioned in the report). Do some psychologists refuse to give this information even when it is requested?

Pi22, as a parent of a child who has had it NOT calculated that was a really really good thing for us, when you have a 3-4 deviation spread between indexes the FSIQ is meaningless but educators WILL look at if it's there and many will not think any further, no matter how many notes the psychologist makes about it's meaningless nature.

MumOfThree, I think you have an excellent point that educators may not be able to look past the FSIQ. It is a shame that educators aren't better trained in understanding the results. My own DS has a 60 point spread (4 standard deviations) between index scores so I do understand the importance of the four indexes, but I also wanted to know his FSIQ since working memory and processing speed are still aspects of general intelligence. So I wouldn't say the FSIQ was meaningless to us.

I'm pretty sure that most of the people who administer the tests don't know how to do the calculation. The whole test is proprietry so I would guess the tables and the computer calculation programme are included in that. I don't suppose that means the calculation as such is propriety - just the manner of use.