Lack of researcher consensus on how to measure disadvantaged students' access to effective teaching has made it challenging for practitioners to draw lessons from the data. This brief aims to help policymakers understand the emerging evidence by synthesizing findings from three peer-reviewed studies that collectively span 17 states. The studies provide two lessons: (1) on average, disadvantaged students received less effective teaching than other students, equivalent to about four weeks of learning for reading and two weeks for math, or about 2 to 4 percent of the student achievement gap between these groups; and (2) access to effective teaching for disadvantaged students varied across districts, with a statistically significant difference between more and less disadvantaged students' access in some districts and no statistically significant difference in access in others. (Contains 11 endnotes, 1 table, and 4 figures.) [For the technical appendix, see ED544676.]