Models of self-regulated learning (e.g., Butler & Winne, 1995; Metcalfe, 2002; Nelson & Narens, 1990; Thiede & Dunlosky, 1999) describe learning as a process that involves setting a learning goal, monitoring progress toward that goal, and regulating study in order to achieve that goal. For example, consider a student preparing for an upcoming test. As the student studies, she monitors her progress toward the goal of mastering the material. If her monitoring indicates that she has not yet mastered the material, she will likely re-study the material until her monitoring suggests that the material has been mastered, at which time she will stop studying. Accurate metacognitive monitoring is critical to effective regulation of study (Thiede, 1999; Winne & Perry, 2000). If someone does not accurately differentiate well-learned material from less-learned material, they could waste time studying material that is already well learned or fail to re-study material that has not yet been adequately learned.