Tracking -- the separation of students into classrooms on the basis of some sort of academic indicator -- is a controversial practice. It is particularly controversial in racially diverse schools, because it tends to introduce racial separation, as noted yesterday in a New York Times article. Here's a well-established but not necessarily well-known fact: in the move from elementary to secondary school, students go to more integrated buildings but sit in less integrated classrooms. Why? The secondary schools serve larger geographic areas and can thus more effectively undo residential segregation. But secondary schools use more tracking than the elementary schools do.
The reason you might not like tracking is because you feel sympathy for the students left out of the gifted classes. They must be worse off, right? After all, they are left with a less-illustrious group of peers, and likely feel some stigma associated with being not gifted.
There is a countervailing impact, however. It's easier to teach a classroom full of students if they are academically similar to one another. I know this first hand from years of experience teaching statistics to graduate students. About a third of my students had prior coursework in statistics and had done pretty well. For them, the class moved too slowly. Another third had never seen stats before; for them the class moved too fast. Very few students, if any, thought the material was being covered at the perfect pace.
So what matters more? The positive impact of better tailoring the curriculum to students, or the negative impacts of stigma and exposure to lower-performing peers? The best study I've seen on the subject used a random assignment strategy: comparing students in 60 tracked schools to those in 61 other untracked schools. The authors found that tracking was beneficial to all students. Even the students barely left out of the gifted track -- barely deprived of exposure to much better peers and all the glory of being called "gifted" -- did better than their counterparts in untracked schools.
The catch with this study, of course, is that the public schools were all in Kenya. It would be wonderful to have a similar randomized trial of tracking in the United States, but who would consent to have their children participate in such a study?
Taking the evidence at face value, we arrive at a conclusion I've forwarded elsewhere: enforcing a one-size-fits-all curriculum in the name of promoting equality is harmful to the disadvantaged. The best argument one might make against tracking is that it benefits gifted students more than it benefits others. But just think about it this way: do you believe so strongly in equality that you are willing to make the disadvantaged worse off in order to pursue it?