There is significant variation in grading between different schools, and across disciplines. Between classes of schools, engineering schools grade lower by an average of 0.15 points, while public flagship schools grade somewhat higher. Across disciplines, science departments grade on average 0.4 points below humanities and 0.2 points below social sciences. While engineering "schools" grade lower on average, engineering "departments" grade comparably to social sciences departments, about 0.2 points above science departments. These differences between disciplines have been present for at least 40 years, and sparse earlier data suggests that they date back 70 years or more.