Fidelity

Implementation fidelity is the degree to which an intervention is implemented as intended. Only by evaluating whether an intervention has been implemented with fidelity can researchers and practitioners gain an understanding of how and why an intervention works, and the extent to which outcomes can be improved. This chapter describes a conceptual framework of implementation fidelity. Originally published by the author in 2007, this framework is perhaps the most cited and used of the available fidelity frameworks to date; this chapter considers the use and development of the framework since that time. It describes a sample of 20 empirical studies that have used the framework to evaluate the fidelity with which an intervention has been implemented and to explore the role of moderating factors. The findings of these studies have then been used to revise and refine the conceptual framework, to create a more up-to-date, evidence-based version, for consideration by scholars and researchers in this field.