Do IQ tests "Top Out"? If so, how?

[Shagnasty]

@nd_n8

I think the flu was kicking my head around this morning otherwise, if I had been a little more lucid, I would simply have asked why the deviation from the mean needs to be set at a standard level across the board, wouldn’t a variable deviation set at a standardized rate of variation better serve to evaluate things at the extreme ends of the spectrum?

It is supposed to be standard hence the name standard deviations. That is just the way statistics works with those things and it has some valuable properties. You need to thing in terms of area under the curve and not the absolute point values. It is very handy to know that +/- one standard deviation covers 68% of the population and so on for other SD’s. For IQ, that means that 68% of people have an IQ between 85 and 115. I didn’t even have to look that up, I just know normal curves and that is the beauty. Anything over 5 standard deviations is getting into the unbelievable range. Normal curves have properties that are extremely valuable in terms of analysis and interpretation.

Of course, it is misleading for the uninitiated (an IQ of 110 is just 30 little points from 140, how big a difference could that make?). It makes it easy to see when people are lying. Start an IQ discussion and you will see point inflation to the point where the group must be the smartest collection of individuals at one place at the same time).

[Bill_The_Cat]

@nd_n8

If High-IQ societies create a harder test (roughly per your estimation of 150-10%/180-90%) then essentially they are either stepping outside of the accepted guidelines and scoring systems, adjusting the standard deviation until the z-number computes (which would be like designing a scientific study around the end result instead of the subject of the study) or establishing a variable equilibrium between the deviation from the mean and the z-number essentially rendering the stability of the mean irrelevant (which is more or less the same as remarking the numbers on a scale to fit the needs of whatever is to be measured). Changing the standard of measurement makes any compairison with anything previously measured (eg. the other 99.9999% of us) irrelevant.

No, the percentile rankings could be cumulative. For example, a standard IQ test can easily place you in the top 1 percent. Then you take another test that basically ranks all the people in the top 1 percent. As long as the tests are similar, you can say you’re the top 1 percent of the top 1 percent, or 99.99th percentile.

[FlyingRamenMonster]

@Shagnasty

I was fiddling around and found out that my IQ can be expressed as (sqrt(weight in pounds) * pi * sqrt(age in years)) / (sqrt(height in inches - length of feet in inches)).

Try it yourself. It is a lot faster and cheaper than taking one of those tests.

22.06

Just as I thought!

[nd_n8]

@Shagnasty

It is supposed to be standard hence the name standard deviations. That is just the way statistics works with those things and it has some valuable properties. You need to thing in terms of area under the curve and not the absolute point values. It is very handy to know that +/- one standard deviation covers 68% of the population and so on for other SD’s. For IQ, that means that 68% of people have an IQ between 85 and 115. I didn’t even have to look that up, I just know normal curves and that is the beauty. Anything over 5 standard deviations is getting into the unbelievable range. Normal curves have properties that are extremely valuable in terms of analysis and interpretation.

Of course, it is misleading for the uninitiated (an IQ of 110 is just 30 little points from 140, how big a difference could that make?). It makes it easy to see when people are lying. Start an IQ discussion and you will see point inflation to the point where the group must be the smartest collection of individuals at one place at the same time).

I think I see, so +/- one SD of a billion people leaves 320 million to work with (still quite a few). If divided evenly on both sides of center that leaves 160 million, or 16% above 115 and below 85 respectively. +/- one more leaves 102.4 million or 51.2 million on each side or 5.1% on each side of 130 and 60. So out of a group of 100 people, 5 of them will statistically be of Very Superior intelligence or better and 5 of them will be moron’s or worse (per the Wechsler scale linked above)? If I got it right this time I can easily see your point about score inflation. I think my failure to understand earlier was thinking of 100 as more of an average than a mean.
Thanks for clearing it up for me (unless I got it wrong again, in which case I’m either going to have to lay off the KitKat bars or buy some bigger shoes and try again)