It doesn't. The fact that the IQ test takes a lot of time means that generally only people who want validation of their high IQ will be motivated enough to take the test.

"Test your fitness with this 1 hour workout! ... Hmm our totally unbiased test shows that everyone is really fit."

See? Unbiased sampling is really hard but an hour long test means you're not even trying. (Which tbf they might not be.)

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brookst 3 days ago | parent | next [-]

“Test your mountain climbing ability by summiting K2!” Hey wow turns out 70% of the population can summit K2!

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kulahan 3 days ago | parent | prev [-]

That’s true of every test, right? Is there a single test where unmotivated people do well?

And an hour is a pretty reasonable ask of most people. How long do you think studies usually take?

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IshKebab 3 days ago | parent [-]

> And an hour is a pretty reasonable ask of most people.

lol no. Most people are not going to spend an hour doing an IQ test. 5 minutes? Sure. Look at how many people here are commenting about it - and HN has a very high concentration of people that love IQ tests.

> That’s true of every test, right?

You can reduce this bias by either making the test a lot shorter (5 minutes) or paying or forcing people to take it (e.g. tests in school don't suffer from this bias).

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kulahan 2 days ago | parent [-]

I don't think you're ever going to get anything that isn't totally useless out of a 5 minute IQ test, and I have no idea why you'd think HN has a high concentration of people that like IQ tests? I mean, maybe conceptually?

Anyways, asking for an hour of someone's time is fine. I really don't believe that dumb people would, for some reason, be particularly short on time. Maybe you're right that we won't get a fantastic sample of people working 4 jobs at once with 8 children at home.

	▲	IshKebab 2 days ago \| parent [-]
		> I don't think you're ever going to get anything that isn't totally useless out of a 5 minute IQ test Depends what you're trying to learn, but yeah it would be difficult. That's not really relevant to whether hour-long tests are biased due to their length though. > I have no idea why you'd think HN has a high concentration of people that like IQ tests? Because it's full of programmers and geeks who value intelligence and generally think of themselves as more intelligent than the average person. This is really obvious IMO. > I really don't believe that dumb people would, for some reason, be particularly short on time. I never said they would. I said that they would be unlikely to invest that free time in an hour long IQ test.