Print, laminate, and cut out bulletin board pieces. Glue the numbers onto expandable files, so students have a place to put their exit slips, quizzes, or tests.
When students finish their assignment they will come up to the board and place their assignment in one of the four folders based on how they feel about the concept. This teaches students to think critically about their own understanding. I have seen the deep thought my students put into this simple task!
I use these to group my students. If a student masters the concept, but doesn’t feel confident, I will not put them in my higher group.