Even if a discussion leader is familiar with the material, good questions may not come to mind spontaneously during the press of classroom interaction. It is easy to get caught up in the moment and let the discussion move into less relevant areas. Prepared questions can be kept on the overhead or on the board to keep everyone on task. Truly controversial and complicated issues are probably best discussed after students have had time to apply the readings to specific questions. Thinking through possible answers should not prevent an instructor from being open to unanticipated alternatives.
Questions can take many forms.
Judgments might be ethical, pragmatic, logical, etc. Suggestions for Facilitating Classroom Discussion Use words with the vocabulary range of the students. This requires a tricky balance between teaching students new words but not intimidating students into not being able to provide an answer because they don't understand the question. Five seconds of silence can seem like an eternity, but students need time to process the question and construct an answer, especially when the question is convergent, evaluative, or divergent. Don't answer your own question.