Outside observers can give instructors valuable formative feedback, and with the right observers and the right instruments, classroom observation can also be a useful (if incomplete) measure of teaching quality. Our guest, Marilyne Stains, teaches in the Department of Chemistry at the University of Nebraska in Lincoln where she specializes in chemical and science education. She has used a range of measures of instructor and student behavior in her research and recently co-authored the largest-ever study of STEM teaching practices that analyzed classroom observation data for more than 2,000 classes. In this episode, we discuss the pros and cons of a variety of classroom observation techniques from reliable objective measures like COPUS to completely unstructured note-taking.