[Excerpt] The purpose of the educational enterprise is LEARNING. Engagement is essential to achieving this purpose. Students must come to school, pay attention, do homework, engage with the subject and construct their new knowledge in ways that allow them to retrieve it later. How are students induced to do all this hard work? Teachers try to make their subject interesting, but sixty–one percent of American students, nevertheless, say they “often feel bored” (OECD 2002 p. 330). Studies of time use in classrooms have found that American students actively engage in a learning activity for only about half the time they are scheduled to be in school. A study of schools in Chicago found that public schools with high-achieving students averaged about 75 percent of class time for actual instruction. For schools with low achieving students, the average was 51 percent of class time (Frederick, 1977). Overall, Frederick, Walberg and Rasher (1979) estimated 46 percent of the potential learning time is lost due to absence, lateness, inattention, classroom disruptions or teachers being off task.1 In 1998, 23 percent of high school seniors reported not being assigned homework or not doing the homework assigned (NCES, Condition… 2001b, p. 41). Studies have found that learning has a strong relationship with time on task (Wiley 1986), time devoted to homework (Cooper 1989; Betts 1996) and the share of homework that is completed. Differentials in time committed to learning are likely to be an important reason for variations in achievement across students and across schools.