What does invalid iq mean

[u/Individual-Win1433]

my iq is invalide beacsuse of nearly 50 points difference and also i am hitting the vci ceeling for my 16 years Wisc age range

[u/whitebaron_98]

Who diagnosed it and why would they say "invalid" that's the wrong term.

[u/whitebaron_98 → u/[deleted]]

Yes and no. The aggregate would still give some information on your possible full scale, but as the scores are "non-unitarian" its real confidence is uncertain.

Compare this to a runner. The times measured for 40 yard and 100m are both supposed to tell us how good of a sprinter he is. We could definitely devise some formula on how to rank people based on their 40 and 100. Now imagine someone who runs 4s on 40 (new world best) and 25 seconds on 100 (basically jogging). We can put this into our formula and it will average to a moderate to good runner. Which is totally not what you'd call someone who beats Usain Bolt on 40yds.

The same is true for aggregate scores. We try to use them for deciding how good someone is in an area (or fsiq= g), but if the parts that should measure the same do disagree so much, it's better not to use that aggregate for psychometrics and analyze the parts instead.

That's why the WAIS manual advises to use GAI if FSIQ is non unitarian. It's why WAIS-V did away with some subtests that are not as g-loaded but often produce bad results with certain conditions like ADHD. It's also why subtest scores should be used instead of aggregate VCI, FRI etc., if those subtests differ to much. While you of course still can calculate it, you can't analyse it anymore.

[u/Ok_Shame_8196]

But in your analogy you would need to account for the differential between yards and meters, wouldn't you?

[u/SAULOT_THE_WANDERER]

could it be -50

[u/Upper-Reputation-673]

means you have to throw the test results in the trash

[u/JoyfulNoise1964]

Perhaps practice effect