This is the first book to gather and address what we have learned about the impacts and challenges of data-intensive teacher evaluation systems--a defining characteristic of the current education policy landscape. Expert researchers and practitioners speak to what we know (and what remains to be known) about evaluation measures themselves, the implementation of evaluation systems, and the use of evaluation data. The authors argue that rigorous teacher evaluation systems have the potential to promote school improvement but only if the systems are carefully designed and implemented and the data they generate are interpreted and used appropriately. This timely and important volume will be relevant and useful to school and district administrators, policymakers, researchers, and teacher education institutions grappling with issues of teacher accountability and school leadership. Book features include: (1) Contributions by scholars working at the cutting edge of research and pioneering leaders directly involved in the implementation of teacher evaluation systems; (2) Examination of the challenges and impact multiple measures-based evaluations are having on teaching and learning; and (3) Empirical research on the reliability and validity of evaluation measures, including classroom observation instruments, value-added measures, student surveys, and teacher portfolios.