There are probably more studies of student ratings than of all of the other data used to evaluate college teaching combined. Although one can find individual studies that support almost any conclusion, for many variables there are enough studies to discern trends. In general, student ratings tend to be statistically reliable, valid, and relatively free from bias or the need for control, perhaps more so than any other data used for faculty evaluation. Nonetheless, student ratings are only one source of data about teaching and must be used in combination with multiple sources of information if one wishes to make a judgment about all of the components of college teaching. Further, student ratings must be interpreted. We should not confuse a source of data with the evaluators who use it – in combination with other kinds of information – to make judgments about an instructor’s teaching effectiveness (Cashin, 2003). This paper summarizes the general conclusions from the research on student ratings.