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Evaluation Studies of the National Center for Education Evaluation and Regional Assistance

Study of the Distribution of Effective Teaching

Contractors: Mathematica Policy Research, Inc.; American Institutes for Research

Background/Research Questions:

Recent Department of Education initiatives, such as Race to the Top, the Teacher Incentive Fund, and the flexibility policy for the Elementary and Secondary Education Act, are designed in part to ensure that disadvantaged students have equal access to effective teaching. This study provides information about the extent that disadvantaged students receive less-effective teaching than other students. The study also examines teacher mobility in participating districts and how patterns of mobility might contribute to unequal access.

The study is addressing the following key research questions:

  • Are low-income students taught by less effective teachers than high-income students? If so, to what extent would providing equal access to effective teachers reduce the student achievement gap?
  • Are there differences between high- and low-poverty schools in teacher hiring, transfer, and attrition? If so, are they consistent with inequitable access to effective teachers for low-income students?


The study is descriptive. It will document the distribution of effective teaching, as measured by value added, and changes in the distribution of effective teaching across the 2008–2009 through 2012–2013 school years. The study will also describe district polices designed to address inequitable distribution of effective teaching implemented during those years. Lastly, the study will examine teacher mobility patterns within participating districts. Data collection includes the annual collection of district administrative records including student achievement to conduct value added analyses as well as annual semi-structured interviews with district leadership to provide information on district policies. Data collection also includes district personnel data to examine teacher mobility within participating districts. The study will be conducted in 29 geographically-dispersed school districts.

Cost/Duration: $8,792,648 over 6 years (September 2010–September 2017)

Current Status:

Data collection and analyses are underway for the final report to be released in Fall 2016. The report on this study will be announced on The first report was released in November 2013 (see An evaluation brief, A Summary of Recent IES Research on Access to Effective Teaching, was released in January 2014 (see

Key Findings:

The first report focused on access to effective teaching in 29 geographically dispersed school districts and found that:

  • On average, disadvantaged students had less access to effective teaching than relatively more advantaged students. Providing equal access to effective teaching for disadvantaged and other students would reduce the student achievement gap from 28 percentile points to 26 percentile points in English/language arts (ELA) and from 26 percentile points to 24 percentile points in math in a given year.
  • Access to effective teaching patterns for disadvantaged students were similar over the three years studied, 2008–2009 through 2010–2011.
  • Access to effective teaching varied across study districts. Access ranged from districts with equal access to districts with differences in access as large as 0.106 standard deviations of student test scores in ELA and 0.081 standard deviations of student test scores in math, favoring relatively more advantaged students.
  • Access to effective teaching was more related to the school assignment of students and teachers than the way that students were assigned to teachers within schools.

The evaluation brief highlighted and summarized three IES studies and found that:

  • Disadvantaged students received less-effective teaching on average. Based on data from 29 districts in grades 4–8 and two states in grades 4 and 5, disadvantaged students received less-effective teaching in a given year than other students in those grades. The average disparity in teaching effectiveness was equivalent to about four weeks of learning for reading and two weeks for math. For context, the overall achievement gap for disadvantaged students in grades four through eight is equivalent to about 24 months in reading and 18 months in math. Study authors estimate differences in teaching effectiveness for one year represent 4 percent of the existing gap in reading and 2 to 3 percent in math.
  • Access to effective teaching varied across districts. The size of the differences in effective teaching in a given year between disadvantaged and non-disadvantaged students varied across the 29 districts studied. The disparities for each district ranged from no statistically significant difference to a difference equivalent to 14 weeks of learning in reading and math in grades 4 through 8.