Different kinds of discussion methods have been developed to help students achieve different kinds of instructional objectives. The following discussion methods are analyzed from the perspective of the role demands that they make of students and teachers: (1) cooperative learning discussions; (2) the subject mastery discussion method; and (3) issues-oriented discussions. Developers of all three methods strongly recommend training students and teachers in their respective roles, and manuals have been prepared to specify role behaviors. In cooperative learning or in subject mastery discussions, the teacher is a resource expert and process observer, rather than a participant, but in issues-oriented discussion, the teacher participates as a moderator. When student discussions do not go well, there may be many explanations, such as role complexity, ambiguity about the nature of knowing, or ambiguity about the curriculum. Analysis of discussion methods indicates that they are most appropriate for helping students construct personal understandings of academic content. Three tables summarize teacher and student role behaviors in the three discussion types. (SLD)