Great one-stop-shop for best practices. Concepts are actionable with options (not requirements) for executing each step. The message really is: establish a vision of quality you share with students so they can self-assess, reflect, and feel capable, through visible incremental gains, of learning. To do this, you need to have evidence (models that meet criteria and models that don't, student work at different stages). It made me think of a line from Charles Olson's "The Kingfishers": "Around an appearance, one common model, we grow up / many." He also writes there, as Chappuis may also mean: "the feed-back proves, the feed-back is / the law."