I, of course, have never done this, but my hunch is that it should be easy to ask students questions that reveal some abilities. I am reminded of one of the st

I, of course, have never done this, but my hunch is that it should be easy to ask students questions that reveal some abilities. I am reminded of one of the studies cited in Gladwell's Blink about how you can thin-slice (speedily evaluate relative merit) a person's abilities in pretty diverse fields (speed-dating, classroom teaching) with only a 10 (or so) second video of the person. No test administered by classroom teachers can escape corruption, unless the teachers are themselves unaware of what constitutes a right answer.