How Did You Get that A? Selectivity’s Role in Rising Undergraduate Grades at a Large Public University

For nearly a century, pre-college standardized test scores and undergraduate letter grades have been de facto industry standard measures of achievement in US higher education. We examine a sample of millions of grades and a half million pre-college test scores earned by undergraduates between 2006 and 2019 at a large public research university that became increasingly selective, in terms of test scores of matriculated students, over that time. A persistent, moderate correlation between test score and grades within the period motivates us to employ a simple importance sampling model to address the question, “How much is increased selectivity driving up campus grades?”. Of the overall 0.213 rise in mean undergraduate grade points over the thirteen-year period, we find that nearly half, 0.098 ± 0.004, can be ascribed to increased selectivity. The fraction is higher, nearly 70%, in engineering, business and natural science subjects. Removing selectivity’s influence to surface curricular-related grade inflation within academic domains, we find a factor four range, from a low of ∼ 0.05 in business and engineering to a high of 0.18 in the humanities, over the thirteen year period.