University of Cambridge Cognitive Ability Test

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?

The benefits have been huge. The Chinese realized this a thousand years ago when they invented civil service exams: https://en.wikipedia.org/wiki/Imperial_examination.

Also, your Vox link was pay-walled, but nevertheless, I am fairly well versed in some of the data. I have my own archive of research on this topic for what it is worth (not likely much).

Any hoot, the correlations, while positive, are nothing to write home about in my opinion. Sure, IQ might have more breadth of predictably, but it definitely lacks depth of predictably compared to more granular models depending on the domain.

For example, IQ is not a better predictor of chess performance than say a chess tournament.