I recently shifted my opinion on IQ tests a bit after watching a recent Veritasium video. He goes into the background/history/controversy of the test as well as some of the concrete impacts of the test and places where it's used. For example did you know the US military has an IQ minimum cutoff? And furthermore they have a second 'soft' cutoff, where only 20% of the military can have an IQ under a certain value. In the past they tried removing this second restriction, but had to reinstate it after seeing increases in casualties/indicators of reduced efficiency! So are IQ tests everything? No. But do they have no merit? Also no. It's somewhere in between.
IQ tests being invalid is more politics than science. Among other things, rejecting the existence of cognitive inequality is necessary to justify systemic racism via the continued existence of Asian quotas (Affirmative Action). Since lots of people benefit from this racism, there’s a huge interest in denial. In western countries, when there’s a few billion people in Asia, and you let a tiny amount in gatekeeping them on the basis of education/wealth/skills, it isn’t really all that much of a shock that they and their children are smarter then average. The only way this could NOT happen is if Asians were LESS intelligent than other groups on average.
IQ tests are hilariously predictive of success if you’re doing a task which is similar to taking an IQ test like academics. They strongly indicate certain mental disorders. Low IQ is more predictive of success than High IQ. Maybe people take the difference between scoring a FSIQ of 110 vs 140 entirely too seriously, but the difference between somebody with 60 vs 90 is staggering.
IQ tests are weakly predictive of academic success, especially on the high end (1SD+). In general, it only predicts 8-25% of variance, even when looking in both directions. That's pretty bad, an average exam does a far better job.
Additionally, the IQ of second generation Asian immigrants will revert to the mean. Not only that, but the advtange decreases rapidly as they age, while the academic advantage grows. And the advantage to begin with is very small - average Asian IQ is only about 2.5 points higher than for Whites, even looking at all generations together.
Given the impact of early childhood environment on IQ, and the huge disparity in academic effort across cultures, esp. those that constitute Asian immigrants, it's pretty clear that the idea that the disparity in Asian achievement cannot be explained by an inherited intelligence advantage. All the data is much more consistent with a culture that just drives students to study far harder.
This does make the argument that affirmative action is harmful even stronger, actually. There is no need to fall back to terrible science to do it. The idea that IQ isn't terribly useful is because it isn't terribly useful, except in very rare cases for diagnosis. The current scientific consensus is consistent with an even stronger argument that AA unfairly discriminates against Asian students.
Not OP, but I understood that to mean any difference in IQ below average (100) has a high impact on success, but differences above 100 have relatively less impact
This is quite a dismissive stance, and I understand the context behind it: IQ was devised to measure broad population academic performance for schoolkids and has big flaws in how it measures that.
But it still has merit as another psychological test battery you can do to determine areas in which you may struggle to process information.
My working memory sucks [compared to the standard for my age range and demographic]. I've had access to stuff like RBANS (Repeatable Battery for the Assessment of Neuropsychological Status), through psychologist friends working in memory clinics. IQ tests correlate that finding, and are much more readily available (ie. free and not locked behind institutional firewalls).
Sure, the most thorough IQ tests are paywalled, but as a concept it's readily available online, though tests will yield you huge variation in scores.
We can choose not to treat IQ as a tool to compare ourselves to other people, but rather as a tool to identify our own strengths and weaknesses within different areas of the test. Ignore the single score at end of test, think on what felt hard, and performance in the score breakdown.
I would love to see more (better designed, statically rigorous) neuropsychological assessments become open and free to access. It would definitely have helped me growing up as an unknown AuDHD kid, to understand I really wasn't "a bright kid just making excuses for things I don't want to do".
That's the only insight IQ scores can give you. But each IQ test tests for something, and IQ being a bunk concept doesn't invalidate that.
Reading comprehension tests test end-to-end ability to process that test and those questions in this circumstance. What comes next? tests test your ability to understand and solve a particular set of puzzles: they're a decent proxy for pattern-recognition skills if you share cultural context with the test author and can handle the administrative overhead of that style of examination. And so on. It's nonsense to give yourself some overall score at the end (though this can make sense for populations), but that doesn't mean the tests are worthless.
If IQ was a bunk concept then the US military could save tens of billions of dollars a year by admitting people who don't meet the current threshold. Imagine the promotion you'd get for saving tens of billions a year, every year, in perpetuity.
