The full set of 36 field-test schools were located in Alaska, California, Colorado, Georgia, Idaho, Iowa, Kentucky, Michigan, Ohio, South Carolina, and Texas. The 11 schools in the year one analysis included six from the Midwest (one urban, one rural, and four suburban), three from the West (one urban and two rural), one urban school from the East, and one rural school from the South. At each site, there were from two to five Core-Plus Mathematics teachers and from one to three comparison teachers. Five of the 11 schools continued into the year two analysis: two suburban, Midwestern schools and three urban schools, one from the South and two from the West.
Among an initial sample of 36 high schools that were field testing the Core-Plus Mathematics curriculum, 11 schools volunteered to administer pretests and posttests to students in both Core-Plus Mathematics and traditional classrooms. The authors state that schools were encouraged to create heterogeneous classroom groupings, although this was not always possible. The authors utilized a stratified matched-pairs design to select the intervention and comparison samples. Students in comparison classrooms were grouped by their most recently completed math course, and then matched to students in the intervention group using pretest scores, school, and gender, in that order. This process was conducted separately during each of the two years of the study (only five of the 11 schools from year one agreed to posttest students in the comparison group in year two). The main analysis included 1,050 students (525 intervention and 525 comparison) in year one and 390 students (195 intervention and 195 control) in year two. Additional analyses (reported in Appendices A3 and A4) varied in sample size, with baseline equivalence information presented separately for each of these samples.
The intervention as implemented in the study included Course 1 and Course 2 of the Core-Plus Mathematics curriculum. The Core-Plus Mathematics Course 1 curriculum was used with ninth-grade students in year one, and Core-Plus Mathematics Course 2 was for tenth-grade students in year two. The authors note that the field-test versions of the Core-Plus Mathematics curriculum used in the study underwent revisions prior to the curriculum’s formal publication.
According to the authors, the nature of the instruction in the comparison classrooms was not specified in advance; a variety of traditional textbooks were used. Comparison classrooms during year one included 20 Algebra, five Pre-algebra, three General Mathematics, and two ninth-grade accelerated Geometry classes. Students in the year two comparison group were enrolled in either Algebra, Geometry, or Accelerated Advanced Algebra.
Student math achievement was assessed using several measures. The full analysis sample for years one and two completed the Iowa Tests of Educational Development mathematics subtest. Slightly smaller numbers of students completed two author-created outcome measures: the Course 1 CPMP Posttest and Course 2 CPMP Posttest. The SAT Mathematics subtest also served as an outcome measure for a subsample of students. For a more detailed description of these outcome measures, see Appendix A2
Support for implementation
From each school, a minimum of one Core-Plus Mathematics teacher attended a two-week workshop prior to teaching a Core-Plus Mathematics course. In this workshop, teachers worked through the course materials by using a small-group investigative approach similar to the one that they would be using with their own students. The comparison teachers had no special in-service program.