Over both recent years and many decades, California districts have produced a range of substantively different approaches to teacher evaluation, demonstrating both the potential for district-level action generally and specific design options. In this report, the authors focus on teacher evaluation programs and further focus on the features of evaluation programs which may promote or hinder teachers' effectiveness in their work. The purpose of this report is to provide an introduction to key issues and evidence for California's policymakers and school leaders who are concerned about teacher evaluation in their districts and schools. The report is organized around four themes of contemporary teacher evaluation programs: (1) evaluation which is based, at least in part, on multiple classroom observations structured by and scored with a detailed rubric; (2) making clear, easy, direct connections between an individual's evaluation results and resources to help that individual in her efforts to improve; (3) evaluation using multiple measures of effectiveness in teaching; and (4) programs which do or do not attach consequences to evaluation results, most notably tenure decisions. For each of these four features, the authors provide examples of different approaches in practice in California school districts. The authors highlight the following five California districts and summarize key features of their evaluation programs: Poway, Long Beach, Los Angeles, San Jose, and San Juan Unified School Districts. For each of the four features, the authors summarize scholarly research which provides evidence on which approaches are more or less likely to promote improvements in teachers' effectiveness at their work. Before taking up the four topics, the authors first report results from a recent survey of California teachers and principals. These results provide some insight into teachers' and principals' current beliefs and attitudes about teacher evaluation in California.