 A second study in 180 colleges, showed a .432 GPA increase from 1960 to 1974, both indicating grade inflation.Stuart Rojstaczer, a retired geophysics professor at Duke University, has collected historical data from over 400 four-year schools, in some cases dating back to the 1920s, showing evidence of nationwide grade inflation over time, and regular differences between classes of schools and departments.Harvey Mansfield, a professor of government at Harvard University, argues that just denying the existence of grading inflation at Harvard proves that the problem is serious.