"If we build it, will it stay?" A case study of the sustainability of whole-system change in London.

Context: The long-term sustainability of whole-system change programs is rarely studied, and when it is, it is inevitably undertaken in a shifting context, thereby raising epistemological and methodological questions. This article describes a transferable methodology that was developed to guide the evaluation of a three-year follow-up of a large health care change program in London, which took place during a period of economic turbulence and rapid policy change.

Method: Using a mixed-method organizational case study design, we studied three services (stroke, kidney, and sexual health) across primary and secondary care.