This works for more than just discussion based classes, as well; one of the best classes I ever took in college was a CS Theory course; every single day, the class started off with a quiz on the material we had covered in the previous class. Immediately after finishing the quiz, we'd go over the answers in class together.
The end result was that you were constantly getting immediate feedback about how well you understand the material; if you thought you knew what you were doing and you were actually totally lost, you found out the very next day and were presented with an opportunity to ask for clarifications. And since there were so many quizzes, there was no need for larger tests (because the professor constantly felt like he had a good handle on how people were understanding the material) and you never got stressed out about bombing a quiz or two (because there were thirty other quizzes that would go into calculating your grade, plus the workshop scores and homework scores).
It really removed the stress of the class and gave me an opportunity to focus on the material itself, instead of worrying about how I would do on the tests. Weirdly, when every day was a quiz, it seemed like there were never any quizzes.