IQ tests are incredibly good at what they're designed for, which is discriminating relatively higher intelligence humans from lower intelligence humans. Also di

IQ tests are incredibly good at what they're designed for, which is discriminating relatively higher intelligence humans from lower intelligence humans. Also discriminating within a single human - they are routinely and reliably used to track cognitive decline. For these purposes they are highly reliable (repeatable, internally consistent) and valid (correlate with ~everything to about the degree one would reasonably expect). They were never designed for machines or non-human animals. Nor were they designed for rare ranges of intelligence - these are by definition hard to create tests for, since it's hard to gather the sample sizes you need. So they work well for the middle ~98% of humans but can't discriminate well among the most profoundly intellectually disabled nor among true geniuses.