The tug-of-war: fidelity versus adaptation throughout the health promotion program life cycle.

Researchers across multiple fields have described the iterative and nonlinear phases of the translational research process from program development to dissemination. This process can be conceptualized within a "program life cycle" framework that includes overlapping and nonlinear phases: development, adoption, implementation, maintenance, sustainability or termination, and dissemination or diffusion, characterized by tensions between fidelity to the original plan and adaptation for the setting and population. In this article, we describe the life cycle (phases) for research-based health promotion programs, the key influences at each phase, and the issues related to the tug-of-war between fidelity and adaptation throughout the process using a fictionalized case study based on our previous research. This article suggests the importance of reconceptualizing intervention design, involving stakeholders, and monitoring fidelity and adaptation throughout all phases to maintain implementation fidelity and completeness. Intervention fidelity should be based on causal mechanisms to ensure effectiveness, while allowing for appropriate adaption to ensure maximum implementation and sustainability. Recommendations for future interventions include considering the determinants of implementation including contextual factors at each phase, the roles of stakeholders, and the importance of developing a rigorous, adaptive, and flexible definition of implementation fidelity and completeness.