Now this makes me wonder. Can someone come up with an interview question that's strongly correlated with engineer ability, but sounds terribly unfair to everyon

Now this makes me wonder. Can someone come up with an interview question that's strongly correlated with engineer ability, but sounds terribly unfair to everyone including the awesome engineer who gets hired because of it? How much additional effectiveness can we buy if we allow ourselves to be arbitrarily unfair, and how much unfairness will that imply?