Comment by rad-b

Working in selection, I can say it’s more nuanced than that. Any measurement can be used as long as it is relevant to the business and related to performance. For example, you’re fine to reject people based on height if you’re hiring basketball players and being higher predicts scoring more points. Or even reject people based on gender (or other protected classes) if you can demonstrate that that specific group is absolutely necessary for you e.g. you want a counselor working with sexual trauma survivors and have evidence that matching patients to counselor on gender gives meaningfully better results for said patients.

The specific cases you mention and the finer point is how do you demonstrate the necessity of a measure? Is high general IQ absolutely necessary for SWEs? Or is it enough to have a high logical reasoning, but don’t need spatial? Do you really need high IQ or is it enough to have a lot of practical experience with hands on skills? Do you need higher IQ to do zero to one development vs code maintenance? The devil’s always in the details with these kinds of questions, and it’s definitely not a blanket “you can’t use anything”.