non-white ethnic backgrounds, and increasing numbers are recent immigrants not yet proficient in English (NCES, 1997c; 1999).

The U.S. teacher population also brings an array of different knowledge bases, expectations, cultural backgrounds, and beliefs to classrooms. Since nearly 90 percent of U.S. K-12 teachers are white (NCES, 2000b), teachers in some schools are demographically quite different than their students.

The individual classrooms within which teachers and students interact constitute the core of the education system. At the same time, what happens in a classroom is significantly affected by decisions made in other layers of this loosely coupled system. First there is the school as an educational unit; setting expectations in certain content areas, the principal, department chairs, or team leaders can affect beliefs about teaching and learning priorities. They can also establish a climate that encourages or discourages particular pedagogical approaches, collegial interactions, or inservice programs (Talbert and McLaughlin, 1993; McLaughlin, 1993; Little 1993). A school’s level of commitment to equity and to providing opportunities for all students to learn the same core content can influence how students are scheduled into classes, which teachers are assigned to teach particular classes, and how instructional resources are identified and allocated.

In the next layer of the system, school districts are responsible for ensuring implementation of state and federal education policies, and often create additional, local education policy. District leaders set instructional priorities, provide instructional guidance, create incentive structures, and may influence the willingness and capacity of schools and teachers to explore and implement different instructional techniques.

The state level is a particularly important one for schools. In the United States, states are constitutionally responsible for elementary and secondary education, and they play major roles in funding and regulating education, providing nearly half of all public school revenues (NCES, 2000a). Each state is responsible for