What's a two-stage exam? Here's an explanation from my forthcoming paper, Physics exams that promote collaborative learning, with Georg W. Rieger and Cynthia E. Heiner:
The two-stage exam is a relatively simple way to introduce collaborative learning and formative assessment into an exam. Their use is rapidly growing in the physics department at the University of British Columbia, as both students and faculty find them rewarding. In a two-stage exam students first complete and turn in the exam individually, and then, working in small groups, answer the exam questions again. During the second stage, the room is filled with spirited and effective debate with nearly every student participating. This provides students with immediate targeted feedback supplied by discussions with their peers.
In the classic exam, students are intensely engaged with the material, but they lose the opportunity for formative assessment, because the feedback is mainly right/wrong and comes a long time after the exam. By contrast, in a two-stage exam, students receive immediate, specific feedback and increase their mastery.
In our two-stage exams, students participated strongly in the discussions, and their reactions were overwhelmingly positive. Even those who found the discussions uncomfortable, because they saw where they had made mistakes, acknowledged that they learned what they needed to learn.