[jldugger]

Standard IQ tests are basically offlimits in the US as they feature a well known, well studied disparate impact.

But I think your correspondent is underselling work sample tests. They are not perfectly correlated with IQ testing, and do in fact measure something beyond IQ; on it's own work sample tests are only slightly worse than IQ testing, and combining IQ testing and work sample testing improves predictions of hiring outcomes vs just IQ testing.

That said, very few workplaces have well calibrated whiteboard interviews, or take home interviews, or pair programming screenings.