Paragraph 3: In schools where time is not being used well, it is unlikely that the addition of more days to the school calendar will lead to higher academic achievement by students. ____________________ if a high proportion of the school day is already being devoted to academic learning time, that is, time when the subject matter being taught is a good "fit" with the student's ability and readiness level, and if high-calibre instruction is occurring, extending the day or year is likely to improve achievement (Aronson et al., 1999). Increasing learning time in that part of the day when students are most likely to be engaged in the learning process may yield small gains.