On the other hand, I wonder if it really produces results that are any better. At least, with a quiz, you can give it to current employees who work great, and discover the quiz turns out to be worthless. (As the author described.)
But with a open-ended question inviting open-ended answers, how can you tell if it's really working? Of the many coworkers I've had before, I can think of one who certainly would have aced the question -- a programmer through and through -- but who was fired after a few months due to poor work ethic and sloppiness. Because while he had enthusiasm for programming, he had no time for "standards" or "teams" or "business needs" -- things like commenting code, communicating well with others, following through on commitments, etc.
So I wonder if the author is going to discover, after a few more months, that there are a few more questions than just this 1 question that also matter just as much...