No matter what side of the ed-policy debate you fall into, getting effective teachers in front of disadvantaged students is a priority for almost everyone. Yet this new study from  Mathematica and AIR highlights just how far we are from ensuring that lower-income kids have access to the same quality of teachers as their affluent peers. The study looked at twenty-nine large school districts (with a median enrollment of 60,000) and calculated for each an “effective-teaching gap”: a measurement that compares the average effectiveness of teaching (using value-added models) experienced by disadvantaged students (those who qualify for free or reduced-price lunch) with the average effectiveness of teaching experienced by their better-off peers. As one might expect, there was a difference. Teachers of affluent students had, on average, a higher value-add than teachers of poor kids, equivalent to 2 percentile points in the student-achievement gap. Interestingly, though, the gap varied across districts and subjects, implying that equity can be achieved. In math, ten of the districts had no statistically significant differences in teacher effectiveness between  poorer and richer students; in English language arts, only two districts could make that claim (perhaps because of deficiencies in low income students’ content knowledge). True, some will resist the use of value-added scores as a proxy for teacher quality, and many studies show just how difficult it is to get effective teachers to switch to tougher schools. But the study does well at defining the scope and implications of the problem we face in creating equal access to effective teachers.

Eric Isenberg et al., Access to Effective Teaching for Disadvantaged Students (Washington, D.C.: National Center for Education Evaluation and Regional Assistance, November 2013).

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