Across the country, there is a renewed emphasis on using teacher evaluation not only to rate teachers but also to give them formative feedback that will help them improve classroom instruction. Recent research shows that applying the strategies that teachers use to give students effective feedback to the teacher evaluation process produces promising results. Tim Westerberg begins this article by asking the reader to take the short diagnostic assessment presented in figure 1. He then asks readers to use the results from the assessment to compare their own beliefs about teacher evaluation with best practices as identified in the professional literature. The survey can also be used to help identify inconsistencies in philosophies and beliefs among members of a school or a district administrative team and introduce a discussion about teacher evaluation and its purposes to a school faculty. Regarding question 1, in opinion surveys that involved thousands of educators, Marzano (2012) found that the vast majority (81%) identified teacher development as the primary purpose of teacher evaluation. The implications of the research for principals and assistant principals who are responsible for conducting evaluations are significant. Administrators who hope to make an impact on classroom instruction are advised to conduct classroom observations by employing several short, unannounced visits, rather than scheduling one or two full period observations; focus on a limited number of improvement targets over the long haul, rather than bombard teachers with different improvement targets after every classroom visit; and involve teachers as partners in the teacher evaluation and development process. To accomplish those goals, feedback to teachers following classroom observations must be focused, specific, and constructive. Principals and assistant principals have precious little time to waste, especially when it comes to the time carved out of their jobs for improving classroom instruction. Feedback to teachers following classroom observations can be one of the most powerful tools for increasing student learning, but only if it is conducted in accordance with the research on effective feedback.