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This article describes the need for, and challenge of, representing the sustainability of a program as a dynamic process. Part of what enhances the complexity of programs is the challenge of dynamic complexity—the complexity of the program evolves over time through the interaction of actors and their environment. This paper describes the need for, and challenge of, representing the sustainability of a program as a dynamic process. The problem is not just one of representation but also of planning—specifically planning for sustainability. We argue that an essential part of any accountability regime is planning for sustainability. Using the concept of programs as dynamic process, we argue that planning for sustainability needs to be a critical aspect of the impact chains of all theories of change. Both the representation and testing aspects of such a formulation are discussed.

This article discusses the utility of realist evaluation in inuencing policies aimed at reducing health inequities and improving population health. Using an example of a National Demonstration program in Scotland, the article discusses how realist evaluation can help in several aspects of policy implementation: exploring "loss in translation" from policy aspirations to program design, interrogating the program design, developing a range of learnings from conducting the evaluation, and aligning the learning with policy priorities. Conditions under which evaluations can lead to positive influence on policy makers and future policies are discussed.