Why Do Some Schools Group by Ability? Some Evidence from the NAEP

Introduction THE PRACTICE OF GROUPING SECONDARY LEVEL STUDENTS BY ABILITY into separate curricular classes (often referred to as "tracking" (1)) has been a controversial one for several decades. Advocates of the practice claim that it allows separate and more appropriate curricula for each group of students, which presumably increases learning for all groups and makes teaching easier. Critics of ability grouping point to studies that show it to be ineffective for most students, potentially harmful for those in the lowest groups, and inequitable along the lines of race and class. While most national educational associations have position statements critical of the practice, (2) it is defended in some quarters, particularly those supportive of gifted students, (3) and is still debated by teachers, parents, and students. (4) While there have been numerous studies that attempt to measure the effect of ability grouping on students, there have been comparatively few studies that analyze which factors cause schools to decide to group their students. Data from the National Assessment of Educational Progress (NAEP) is nearly unique in that it provides a nationally representative sample of schools and contains information for each school regarding the potential determinants of the grouping decision, as well as data on whether or not each school groups its students by ability. The NAEP data therefore provide a unique opportunity to shed light on which factors are most important to schools when they decide whether or not to group their students. Knowing the reasons behind schools' tracking decisions is important. If schools choose to track based on the number and achievement diversity of their students, they probably have the best interest of students in mind, and the practice may be defensible (although perhaps misguided). However, if some schools track because they wish to separate students by race and class or for some other reason not related to student achievement, then it is much less defensible. II Literature Review THE LITERATURE ON THE EFFECTS OF ABILITY GROUPING ON STUDENTS is voluminous. The most frequently cited of these range from those that indicate it to be generally effective, especially for high-ability students (e.g., Kulik and Kulik 1982), to those that indicate it to be ineffective for all students (e.g., Slavin 1990), to those that conclude grouping to be quite inequitable and actually harmful for low-ability students (Oakes 1985). More recent studies have failed to create agreement on either the effectiveness or equity of grouping by ability (Argys, Rees, and Brewer 1996; Betts and Shkolnic 2000; Figlio and Page 2001; Gamoran et al. 1995; Hallinan 1994, 1996; Oakes 1995; Wheelock 1992), although there is somewhat of a consensus that the effects favor those placed in the higher-ability groups. The literature that sheds light on the pervasiveness of ability grouping and the causes of schools choosing to engage in ability grouping is much less extensive. National studies of the prevalence of tracking show that a majority of schools do engage in it to some extent (Loveless 1998; Rees, Argys, and Brewer 1996), but that the practice is nowhere near universal, as some authors have suggested (Oakes 1987). (5) Although there are some studies that explore the determinants of the type of tracking that schools engage in (e.g., Kilgore 1991), only a few contain any evidence explaining the decision of whether to group by ability. Hallinan (1992) reports that, in a small sample of Midwestern schools, tracking policies did not vary across schools with differences in ability distributions. Braddock (1990) finds that tracking is more prevalent in schools with substantial enrollments of minorities. Perhaps the only research to directly examine the question of why some schools group by ability and others don't is by Loveless (1999), who studied several hundred schools in California and Massachusetts. …