Instructor evaluation forms--those scannable surveys that students use to rate the quality of their instructors and courses at the end of every term--are the most common method of assessing teaching effectiveness in the United States. A considerable body of research on end-of-course evaluations suggests that student ratings are valid sources of accurate information on particular teaching behaviors. Students are not adequate judges, however, of course content, since expert knowledge is required to assess substantive elements of a course. Quantitative student ratings of instruction therefore provide only a portion of the information required to fully evaluate teaching. Faculty members in search of diagnostic feedback that can be used to improve their teaching and administrators who understand the need for more holistic appraisals of teaching effectiveness require more information about teaching efforts than that supplied by end-of-course surveys. In this article, the authors identify and discuss qualitative sources of evidence and methods of assessment that can provide important and detailed information on the quality of teaching in a course or program. They also describe potential sources of information about and methods for assessing teaching effectiveness that can serve to expand conventional ways of thinking about summative evaluations of teaching and contribute to instructional improvement.