As a follow up to this, yes, 15 tends to be the standard deviation. However, most, if not all tests have a cap to the highest score they can return, which is about 160. I believe this is the case for both Stanford-Binet as well as Weschsler (WISC):

https://en.wikipedia.org/wiki/Stanford%E2%80%93Binet_Intelli...

https://en.wikipedia.org/wiki/Wechsler_Intelligence_Scale_fo...

I don't know for sure, but I suspect that one of the reasons that 160 is the max score is that the tests need to be normed and that's difficult to do once you pass so many standard deviations.

As another note, the overall composite score can qualify a student for services in a public school, but a good diagnostician will be using the test to assess areas of strength and weakness. Basically, a student who has high spatial reasoning, but poor verbal IQ requires different assistance than the reverse.

Anyway, yes, I'll agree that I hate IQ measuring contests because they're just like the other anatomical measuring contests. Further, if even someone wants to have one, they're almost never about the results from a properly normed test like those from above and, further, those tests contain a lot more information than a single number.

Thank you for clarification. I also like your comparison with NBA and A-actors. I am Mensa member which means my IQ is in top 2% of the general population of my country. Because of the membership and my active involvement, I know a lot of people with high IQ. And my conclusion is that IQ doesn't mean too much. Yes, I think that some of them are very smart, but not genius level smart. Not even close. In my opinion, the usefulness of the IQ metric is very questionable.

I'd say the comparison is not quite right, as everyone can be assigned an IQ (however useful that may be), but not everyone aspires to be an NBA player or A-List actress.

How do you assign an IQ to someone who doesn't want to be tested?

You don't have to, you can just use basic statistics for that, because the pool of people who have an IQ is everyone.

The pool of people who aspire to be NBA players or A list actresses is not everyone though, so you have to estimate first the respective pools.

False. Aspiration is a red herring.

You can just as easily use statistics to assess whether an individual possesses the traits to become an NBA player or actress as you can assess their IQ without their cooperation.

Conversely if someone doesn't want to participate in IQ testing, it is equivalent to them not wanting to play in the NBA.

There is no doubt that you can DEFINE this to be equivalent. But then you are measuring something different from what I am interested in.

I'm not doing anything with definitions. You have introduced an arbitrary distinction which is based on no measurable characteristic.