- Brevity - clear, concise and self-evident
- Ambiguity - the learner needs to explore the prompt in his or her own way - it shouldn't be too prescriptive
- Immunity to assessment - if students care about what they are doing, they will want to do a good job. They will be collaborating, peer reviewing and editing, making adult assessment unnecessary.
A good unit of inquiry or project goes beyond simply having a good prompt. In addition, Gary writes, learners also need appropriate materials, sufficient time and a supportive culture, including a range of expertise. What we need to is give students a prompt and then let them follow their ingenuity. Gary says that "the richest learning often results from getting in over one's head or when encountering unforeseen obstacles ... good prompts do not burden a learner, but set them free."