“…They have typically considered isolated characteristics of curriculum materials, such as the range of topics covered in the material (e.g., Chiapetta, Sethna, & Fillman, 1993), the level of difficulty of the writing (e.g., Vachon & Haney, 1991), the use of illustrations (e.g., Holliday, 1990), attention to student diversity (e.g., Bazler & Simonis, 1991;Potter & Rosser, 1992), or the extent of inquiry focus (e.g., Eltinge & Roberts, 1993).…”