Students have a tendency to study for the test instead of studying to learn the information. They will cram for a quiz/test and then immediately lose all of the information at the moment they turn it in. This turns an assessment of progress into an assessment of short-term memory. One solution I've found is to schedule time in class for the students to "convince" me that their answer makes sense. They put more effort into studying their books this way. They want to know where the answers are. This actually works as a time saver for me, since it reduces the amount of in-class review time I need per quarter for my cumulative finals.