This issue presents a thorough analysis the use of student evaluations of teaching for summative decisions and discusses the ongoing controversies, emerging research, and dissenting opinions on their utility and validity. The authors summarize the role of student ratings as tools for instructional improvement, as evidence for promotion and tenure decisions, as the means for student course selection, as one criterion of program effectiveness, and as the continuing focus of active research and intensive discussion. They also examine ratings myth and ratings evidence, explore the constant quest to prove or disprove the existence of biasing factors, and present provocative suggestions for new directions for research and practice. The volume concludes with a three-part debate beginning with Philip Abrami's proposed mathematical means for facilitating the correct summative decisions about instructor effectiveness based on student ratings; reactions and opinions to Abrami's theory from practitioners; and Abrami's rebuttal. With a review of the current literature on student ratings and a set of guidelines for good evaluation practice, this is an indispensable tool for institutional researchers committed to improving judgements by improving the precision of their measures.This is the 109th issue of the quarterly journal New Directions for Institutional Research.