Tim O'Keefe: As we create questions for our test, if someone asks a yes or no question, some of the other kids might be kind and say, "Well that should be in the true/flase section." I do think there is a place for that. But the most powerful thing, the thing that would show me whether children truly understand a subject are the kinds of questions where - "What do you think about this?" or "Explain this," or "Draw a diagram that demonstrates something else." Those are the questions that as a teacher informs me about what kids know.