Know that sense of impending doom when you’re not prepared for an exam? Some educators think this feeling may be worth the pain. “Pretesting,” or taking — and probably failing — a final exam at the beginning of a course, might be a good way to learn new skills and rewire your thinking about the material you’re about to study. Not convinced? A recent trial showed that students who had “pretested” before taking a class did 10 percent better on their final exams than those who had not.