Evaluators who are interested in developing or improving a program or policy frequently look to formative evaluation as a guiding framework. This book shows why those hoping to use evaluation to drive change in complex systems, rather than develop or improve one program, policy, or product, need to shift from the oversimplified idea of formative evaluation to a more specified continuous improvement model grounded in improvement science. In doing so, author Kristen L. Rohanna provides guidance to both evaluators and others, such as K-12 educators or hospital administrators, who lead improvement initiatives in their organizations and seek to solve persistent problems of practice. The book includes an extended case study: a networked improvement community of five public middle and high schools.