Adjusting GPA to Reflect Course Difficulty

The computation of Graduate Point Average (GPA) incorrectly assumes that grades are comparable across courses and instructors. GPA overstates the performance of students who elect an “easier” course of study relative to those who choose a more “difficult” course of study. This paper proposes a method of adjusting GPA and applies it to data from one cohort of undergraduates at Carnegie Mellon University. Adjusted GPAs are more highly correlated with students’ high school Grade Point Average and with SAT scores than are the raw GPAs or GPAs adjusted using a prominent alternative method, Item Response Theory. A survey of students finds that the new methods’ estimates of relative course difficulty are consistent with students’ perceptions of relative course difficulty.