In recent years, there have been increasing calls from the government and other organizations to provide easy public access to student evaluations of teaching. Indeed, the increasing ease of displaying and viewing large quantities of information, and competition among universities and majors for students, makes it likely that an era of greater transparency of this type of information is at hand. While students' evaluation of teaching (SET) is one quantitative metric that rates the instructor, it may be influenced by factors that are often beyond the instructor's control. In this study, we analyze a longitudinal data set from both engineering and business schools of a large public university, and identify factors that influence SET. We show which factors have the highest influence on overall SET scores, and contrast these between engineering and business colleges. Colleges within the same university may have differences in the factors affecting SET, and recognition of this is important in effectively and fairly evaluating SET scores. We also provide recommendations regarding information that should be displayed along with the SET, particularly when SET scores are made public, so that instructors are not unduly penalized when their evaluations can be influenced by factors over which they have no control.