school-based decisions about class scheduling and the time allotted for science, technology, or mathematics instruction can influence the quality of the programs offered to students (Council of Chief State School Officers [CCSSO], 1999b). For example, programmatic “tracks”—combined with expectations about what particular students can or should learn, and what should be taught to whom— often reflect school or district level policy (Oakes, Ormseth, Bell, and Camp, 1990; White, Porter, Gamoran and Smithson, 1996).
The curriculum channel is linked to the other components of the education system in multiple ways. Teacher development programs, the use of assessment and accountability to spur educational reform, and public influence on policy decisions may directly affect the school curriculum. These factors will be addressed in later chapters.
Instructional materials represent the resources that teachers use to develop student understanding of subject-specific concepts and skills in the enactment of the curriculum. Such materials include textbooks, workbooks, laboratory manuals, manipulatives such as three-dimensional solids, laboratory supplies and equipment, videos, laser discs, CDs, software, and websites. Developed by many different entities, instructional materials often become critical, defining components of instructional programs (CCSSO, 2000; Weiss, 1991; Stake and Easley, 1978). In particular, commercial publishing firms with K-12 divisions dedicated to producing and selling school textbooks are central players in shaping what most teachers teach (Woodward and Elliot, 1990; Tyson, 1997). Educational material production is “big business”—in 1999, revenues from K-12 instructional materials of the top five publishers totaled over $3.3 billion (Walsh, 2000). Thus, although publishers can and do produce materials in response to particular educational changes, decisions to invest in such development are always tempered by estimates of the potential demand for materials