This report summarizes findings from a two-year study of Chicago's Excellence in Teaching Pilot, which was designed to drive instructional improvement by providing teachers with evidence-based feedback on their strengths and weaknesses. The pilot consisted of training and support for principals and teachers, principal observations of teaching practice conducted twice a year using the Charlotte Danielson Framework for Teaching, and conferences between the principal and the teacher to discuss evaluation results and teaching practice. Although the findings from this report focus on a specific pilot in a specific city, they have broad implications for districts and states nationwide that are working to design and develop evaluation systems that rely on classroom observations to differentiate among teachers and drive instructional improvement. Overall, the authors found that the Excellence in Teaching Pilot was an improvement on the old evaluation system and worked as it was designed and intended, introducing an evidence-based observation approach to evaluating teachers and creating a shared definition of effective teaching. At the same time, the new system faced a number of challenges, including weak instructional coaching skills and lack of buy-in among some principals. Specific findings include: (1) The classroom observation ratings were valid measures of teaching practice; (2) The classroom observation ratings were reliable measures of teaching practice; (3) Principals and teachers said that conferences were more reflective and objective than in the past and were focused on instructional practice and improvement; and (4) Over half of principals were highly engaged in the new evaluation system. Appended are: (1) Charlotte Danielson Framework for Teaching Modified for Use in Chicago Public Schools; (2) Chicago Public Schools Evaluation Checklist; (3) Danielson Framework Training for Pilot Principals and Teachers; (4) Quantitative Data and Statistical Models; and (5) Qualitative Data and Analytic Methods. (Contains 13 tables, 17 figures and 23 endnotes.) [This paper was written with Stuart Luppescu, Kavita Kapadia Matsko, Frances K. Miller, Claire E. Durwood, Jennie Y. Jiang, and Danielle Glazer. For the first year report, "Rethinking Teacher Evaluation: Findings from the First Year of the Excellence in Teaching Project in Chicago Public Schools. Policy Brief," see ed512286.].