The central challenge for American schools is to produce much higher levels of achievement for the vast majority of students. National attention to new Common Core Standards and to 21st Century Skills is based on this challenge. The policy debate we need to have is about how to accomplish this.

I am not persuaded that the elimination of tracking, a popular idea in the 1980s and 1990s, has had a negative impact on high-achieving students, although I am aware of arguments to that effect. I have seen studies espousing the benefits of ability grouping and accelerated learning opportunities for high achievers. I have not yet seen the evidence showing that high-achieving students suffer when grouped with other students. To the contrary, high achievers are often characterized as interested, attentive and hardworking.

In fact, I am not persuaded that we have eliminated tracking. In many American high schools, tracking is alive and well, especially in the suburbs. Achievement data are still used to place students in programs or tracks, along with grades, teacher recommendations and, if need be, parent advocacy.

Where you go to school matters. For instance, a recent study of what determines a high school’s inclination to offer Advanced Placement courses suggests that parent and student demand is key. The authors suggest that demand for rigorous courses is weak in communities serving low-income students. In my opinion, this is where issues of fairness surface, because much of the evidence on tracking reveals that in schools serving high concentrations of poor children, students are more likely to be routed to curricular streams that do not clearly lead to post-secondary education or other valued options. Policy attention needs to be directed toward increasing the demand for rigor in these communities — and even more so, to increasing the capacity to offer rigorous programs.

Differentiated instruction is, to me, another matter altogether. It is what happens once the class is assembled. The teacher's job is to figure out how to get every student to meet the learning objectives of the course. It is when the students vary in knowledge and skill that the ability to differentiate instruction is important. Using a variety of teaching strategies and organizing classrooms in different ways can be beneficial when it optimizes the conditions for learning.

But that’s just the ideal. The truth is, too few schools establish the conditions for teachers to perfect these strategies. This is why practices like tracking are so durable; they simplify teachers' lives. If, as I suspect, tracking is still widely practiced, then I hope that even in the “general” and “developmental” tracks, teachers are helping student reach high targets. I am probably naive, but it is the right way to think about it. Above all else, it means that no one is shortchanged in the process.