Differential Grading in North Carolina Public High Schools

College admissions decisions often rest heavily on a student’s high school grades, but teachers have significant flexibility in how they assign grades. Differential grading occurs when students are held to different grading standards in courses with the same curriculum and content. It may be due to various factors, including differences in teacher grading standards, district grading policies, student characteristics, teacher quality, and curriculum adherence. If it occurs systematically between districts, schools, or student characteristics, then certain students may receive higher or lower grades relative to other students, despite having the same content mastery or ability. Statewide end-of-course (EOC) tests provide one way to measure differential grading patterns. Using three years of statewide data on five subjects in North Carolina public high schools, I find that districts with similar EOC test score averages have average course grades that vary by as much as a letter grade, or 0.6 standard deviations. In addition, student characteristics are stronger predictors of differential grading than teacher, school, or district characteristics. Female, Limited English Proficient (LEP), and 12th grade students earn statistically significant higher grades than other students in all five subjects, holding test scores and teacher, school, and district characteristics constant. Low-income students, conversely, earn lower grades than other students, all else constant. Due to this differential grading, North Carolina educators and policymakers should think carefully about removing EOC tests from the curriculum. In addition, they should consider how to reduce differential grading and its impact on college admissions.