Students who qualify for federal lunch subsidies receive less effective instruction in school, on average. And that disparity appears to be a function of the schools those students attend, rather than the classes they’re assigned, concludes a federally financed study released last week.
Although a handful of other studies have reached similar conclusions, this analysis stands out for its breadth. It looks at 29 school districts, from medium-sized to very large, located all throughout the United States. (The study does not identify the districts.) The median district size was 60,000 students.
Analysts from Mathematica Policy Research examined test data from students in grades 4-8 in the districts, and used a value-added analysis to calculate the average effectiveness of teachers for all disadvantaged students in in each system. This figure was subtracted from the average effectiveness of teachers for all non-disadvantaged students. (Value-added is a statistical way of isolating teachers’ impact on their students’ academic gains.)
In all, the study finds a statistically significant gap in overall teacher skill amounting to a difference of about 2 percentile points in the achievement gap between the two groups of students. For instance, in math, if disadvantaged students had had equally good instruction, the achievement gap would have fallen from 28 to 26 percentile points.
When broken out by district, gaps in teachers’ skill were much larger in some districts than in others, as the chart below illustrates.
Source: U.S. Department of Education
A version of this news article first appeared in the Teacher Beat blog.