ABSTRACT
Commercially published, traditional textbooks predominate mathematics curriculum materials in U.S. classrooms and, to a great extent, determine teaching practices (Goodlad, 1984), even in the context of reform efforts (Grant, Peterson, & Shojgreen-Downer, 1996). Various standards (NCTM, 1989, 2000) and state and local curriculum frameworks are designed to govern or at least guide these materials. However, publishers attempt to meet the criteria of all such frameworks, including scope and sequence requirements, and thus the educational vision of any one is, at best, diluted. This results in “mile wide, inch deep” (NCES, 1996) curricula that are a primary cause of the poor performance of U.S. students in mathematics (A. Ginsburg, Cooke, Leinwand, Noell, & Pollock, 2005; Kouba et al., 1988; McKnight, Travers, Crosswhite, & Swafford, 1985; Mullis et al., 1997). Problems exist both in the quantity of topics that are treated and how they are treated (Clements & Battista, 1992; A. Ginsburg, Leinwand, Anstrom, & Pollock, 2005; Porter, 1989). In one main focus of study, geometry, for example, textbooks are not only ineffective in promoting higher levels of geometric thinking (Fuys, Geddes, & Tischler, 1988), they often hinder students’ development of this thinking (Jaime, Chapa, & Gutiérrez, 1992; Mansfi eld & Happs, 1992).
