Academic departments assign different relative weights to the importance of teaching and research. Those weights are used in making decisions about promotion, tenure, and annual raises. Presumably, raising the teaching weight should encourage faculty to increase time on teaching. Using survey data from U.S. faculty in 1995, 2000, 2005, and 2010, researchers show that at different schools teaching weights overlap extensively but vary, and that within different types of schools, those weights vary systematically based on class sizes in principles and intermediate theory courses, school or enrollment size, and for faculty who are assigned to teach principles classes. If departments and schools use teaching weights as a discretionary policy, successful implementation likely depends on adapting the policies to fit school, department, and faculty characteristics.