Measuring educational opportunity is a topic of interest to policymakers and education stakeholders alike. Standardized assessments of student achievement are commonly used to measure educational opportunity in North Carolina and across the nation. This research brief examines two measures of educational opportunity in North Carolina public school districts. Both measures are based on standardized assessments of student achievement. The first measure--"average achievement"--indexes the average level of student achievement at a single point in time. The second measure-"achievement growth"--indexes the rate of growth in student achievement over time. The findings and policy implications are discussed, followed by a technical appendix to further describe the data and analyses.