Between good intentions and great results lies a program theory--not just a list of tasks but a vision of what needs to happen, and how. Now widely used in government and not-for-profit organizations, program theory provides a coherent picture of how change occurs and how to improve performance. "Purposeful Program Theory" shows how to develop, represent, and use program theory thoughtfully and strategically to suit your particular situation, drawing on the fifty-year history of program theory and the authors' experiences over more than twenty-five years. This book is divided into five parts. Part I, Key Ideas in Program Theory, contains the following chapters: (1) The Essence of Program Theory; (2) Variations of Program Theory over Time; and (3) Common Myths and Traps. Part II, Assessing Your Circumstances, contains the following chapters: (4) Scoping Intended Uses; and (5) The Nature of the Situation and the Intervention. Part III, Developing and Representing Program Theory, contains the following chapters: (6) Processes to Identify or Develop a Program Theory; (7) Developing a Theory of Change; (8) Developing a Theory of Action; (9) Representing Program Theory; and (10) Critiquing Program Theory. Part IV, Resources for Developing Program Theory, contains the following chapters: (11) Some Research-Based Theories of Change; (12) Some Common Program Archetypes; and (13) Logic Models Resources. Part V, Using Program Theory for Monitoring and Evaluation, contains the following chapters: (14) Developing a Monitoring and Evaluation Plan; (15) Causal Inference; and (16) Synthesis and Reporting. Figures, tables and exhibits are also included.