When Ron Hoeflin set out to to measure the smartest one in a million level he had a major advantage that he was smart enough to exploit. Every year (at the time), about 3.5 million Americans become old enough to take the SAT and virtually 100% of the smartest people actually do, thus the 3 to 4 people who scored perfect on the SAT each year were one in a million level minds. This allowed him to norm his own high ceiling test because he noticed that a 43+ on the Mega Test was about as rare among Mega Test takers as was a 1600 on the SAT.
But what if instead of trying to make a super high ceiling test, he was trying to make a super low ceiling test, to recruit the dumbest one in a million (normalized deviation IQ below 30). This test would have items like “say DaDa”.
One problem with norming this test is there’s no anchor test that’s taken by all dumb Americans the way the SAT is taken by all smart Americans. So how would you find the dumbest Americans? It used to be all severely disabled minds were institutionalized so you could just go to all the institutions in America and ask to test the lowest functioning young adults there (controlling for age is important). Of course there wouldn’t be a perfect correlation between who they considered the dumbest and who actually scored the lowest, so you’d have to test perhaps the entire bottom half of every institution to make sure you tested all the dumbest minds (not counting people who are in a coma since they’re arguably untestable, not stupid per se).
If I were as rich as Elon Musk, I might spend a few billion trying to find the dumbest people in America but then I’d be harassed by people like Elizabeth Warren and Bernie Sanders who would accuse me of being cruel and use it as a another excuse to tax my wealth and the twitter mob would be on their side.
It would be interesting to see if you could actually pin down the dumbest one in a million or if even the easiest test imaginable would have too many people scoring zero.