 Isely and Singh (2005) find it is the difference between the grades students expect to receive and their cumulative GPA that is the relevant variable for obtaining favourable course evaluations.Another paper by Carrell and West (2010) use a data set from the U.S. Air Force Academy where students are randomly assigned to course sections (reducing selection problems).It found that calculus students got higher marks on common course examinations when they had instructors with high SET scores but did worse when they took later courses requiring calculus.