After over a century of psychometric research in cognitive abilities and intelligence, what do we have to show for it? Whose life has actually improved for the better? Have the benefits from such research, if any, outweighed the amount of harm that has already been caused?
I'm not certain I agree. If anything, cognitive tests can be used as a single point of datum, but to my knowledge, no condition can be diagnosed via a cognitive test alone. Of course, I could be mistaken. I wish administered the WAIS-IV on top of many other tests for an ADHD diagnosis.
> They are important to determine exactly what sort of ongoing care and support the person needs in order to thrive.
Interesting, upon my receiving my diagnosis, I was not provided any support nor would I declare I have thrived. Obviously, n = 1. I was merely given the social approval to take pharma-grade speed and thrown back to the wolves.
> It's also not arbitrary—a good cognitive test will give insight into the ability to perform everyday cognitive tasks.
That's the part I believe I am clearly missing. These tests provide insight into the ability to perform everyday cognitive tasks better than one's history of already performing various tasks? It's not as if someone with a perfect SAT score takes an IQ tests and then is met with the sudden reality that they are mentally disabled nor vice versa.
What do these tests tell us that we already do not know? If I want to find someone with high mathematical abilities, then I would administer a math exam. Reading? Reading exam. Chess? Chess tournament. And so on...
The sub-sections of things like the WAIS can be of some value for identifying specific abnormalities or deficiencies, but as you said, is probably of more value clinically to split them out into separate tests/activities rather than to group them all together into an aggregate score. It's a bit like judging athletic ability and skill by BMI and fat percentage rather than just playing an opponent in tennis to find out if they're a good tennis player.