This report summarizes research literature on multiage classrooms, explaining how they operate, and describes a study of a low-performing, predominantly Native American school district which adopted multiage classrooms as its primary reform strategy. District teachers completed surveys about: planning; collaboration; student groupings and interactions; assessment; planning resources; preparedness; faculty development; perceptions about the effects of multiage classrooms and looping on student learning; opinions on advantages and disadvantages of multiage classrooms and looping; and suggestions for improving instruction and learning. Researchers observed 37 classrooms and interviewed principals and district administrators. They also collected data from a comparison school in a neighboring district that had successful multiage grouping. Teachers were dissatisfied with how multiage classrooms were mandated by district administrators. The mandate created camps of teachers divided over the issue. Teachers tended to feel incompetent, requesting more training and development. Teachers mentioned needing more materials and resources for these classrooms. They did not feel prepared to teach multiage classes. Little time was devoted to teacher collaboration, though it was considered important. Strong support from principals was important. Administrators believed the multiage approach had potential for reform of instruction. Three appendixes present study letters, forms, and surveys. (Contains 32 references.) (SM)