Measuring Content Through Textbooks: The Cumulative Effect of Middle School Tracking

This chapter demonstrates a method to summarise instructional materials that can be used to distinguish different types of curriculum. Using a US national longitudinal sample, indices derived from textbook content coverage were used in quantitative analyses to illustrate curricular differences. Textbook data collected from mathematics teachers of public school students from grades 7 through 12 were coded to capture content and performance expectation intended by the textbooks. Different approaches were examined to quantitatively summarise the data to characterise students' exposure to mathematics content. The results were tested against the expectation of the long term effects of tracking in the US middle schools. By grouping students by the type of courses they took in seventh and eighth grades, different approaches to defining the "amount" of mathematics exposure in the subsequent years were compared, each capturing different characteristics of the mathematics contents represented in the textbooks. The results showed that students who enrolled in Algebra prior to ninth grade were exposed to almost three times as much of mathematics contents as students when did not take algebra in secondary school. The gap in exposure persisted when contrasting these students with other students who had algebra in high school though to a smaller extent. As it is broadly accepted that textbooks are a good reflection of the implemented curriculum in most countries and a particularly accurate reflection in the US, the Chapter concluded with an a path analytic model showing that exposure to demanding curricular coverage in mathematics strongly predicted the mathematics achievement