Why Do Some Schools Group by Ability?

A bstract .   This article explores the reasons that schools choose to group their students by ability. A mathematical model suggests that high diversity of achievement and a large number of students in a school will cause a school to be more likely to group. Less legitimately, some schools may choose to use ability grouping to segregate students by race or class within a school.
The data used in this study come from the 1992 NAEP 8^th grade Mathematics Assessment. Cross-tabulations suggest that ability grouping is correlated with diversity of student achievement, the number of students, racial diversity, and low levels of poverty. The mean achievement of students and school spending levels do not have much correlation with the schools' tracking decisions. Logit regressions indicate that the number of students in a school and its racial diversity are most important, and that other factors (most notably the diversity of achievement) are not. These results lend credence to those who suggest that grouping is not necessarily done for academic reasons, but rather is a subtle way to segregate by race or class.