MASTERY LEARNING classes are run on the assumption that nearly all children can learn a subject well, once they have been taught its prerequisites. The teacher instructs the whole class as a group, stopping after each learning unit to give a diagnostic test. Each student gets precise feedback from these tests (but no grades) and must master 80 percent of the objectives of a learning unit before going on to the next.

Students who have failed to master the unit are re-taught the specific items they missed (in a different way) and do corrective work, frequently in pairs. Then they are re-tested. Meanwhile the others do "enrichment activities." Then everyone goes on to the next unit.

At the end of the course, students take an exam to see how well they have mastered the objectives of the learning units. Their performance is measured against specific learning standards, rather than against the performance of other students, and it is possible for nearly all students to get an A.

According to several studies, the average student in a Mastery Learning class does as well as the top 15 percent of students in a conventional class -- even when taught by the same teacher.