Student evaluations of teaching (SETs) provide both summative and formative feedback. Although it is clear that SETs are used by administrators for summative purposes, such as providing data to support personnel decisions, it is uncertain how instructors use them for formative development such as to inform overall teaching practice. The objective of our study was to determine the frequency and nature of SET use for formative purposes, to explore the perception of SET utility to inform teaching practice, and to determine how perception of SET utility might be improved to enhance its use in a formative context. Participants were all biological sciences instructors at a large, research-intensive University. This research was conducted in two phases, using a combination of focus groups, interviews, and a survey to yield both qualitative and quantitative data. We found that while instructors generally perceive that SET feedback has formative utility, and that most instructors have used SET feedback for formative purposes at some point, there are many elements of SET administration that they are dissatisfied with, and they suggest several ways in which SETs could be improved (such as allowing in class time for SET administration or doing multiple administrations per semester) to yield more useable feedback that could inform their teaching. The results of this study can be used to further inform the ongoing debate about the role that SETs should play in higher education, as they demonstrate both the utility and concerns about using SETs for formative purposes.