This article examines the teacher's contribution to the indirect effect that within-classroom grouping has on student achievement. Two distinct types of groups (ability groups and peer work-groups) are discussed and recommendations made for effective use of within-class grouping. (IAH)

Mastery learning can be described as a set of group-based, individualized, teaching and learning strategies based on the premise that virtually all students can and will, in time, learn what the school has to teach. Inherent in this description are assumptions concerning the nature of schools, classroom instruction, and learners. According to the…