Are our students learning? Are they developing? Are we having an impact? These questions are only a small sample of those that faculty ask before, during, and after each course that they teach. Faculty often attempt to answer such questions using the evidence they have—student remarks during class and office hours, student performance on examinations or homework assignments, student comments solicited via teaching evaluations, and their own classroom observations. While these forms of evidence can be useful, such informal assessments also can be misleading, particularly because they are generally not systematic or fully representative.