There have been recent concerns about the failure of several global health interventions. Interventions are considered to have failed when they are unable to achieve the intended results. Failure may be linked to how the intervention was designed (design failure) or how it was implemented (implementation failure). Recently, substantial efforts have been employed to improve the outcomes of health interventions. These efforts have led to the development of several theories, models, and frameworks in implementation science to improve the quality of implementation, bridging the divide between evidence and practice. But significant gaps still exist. Whereas much work has been done to develop frameworks and approaches to improve implementation fidelity, not as much effort has been done to guide the adherence of interventions to program theory during the design of the programs. Further, there have been concerns about the applicability of these frameworks in the real-world. This article uses examples to illustrate these gaps and further proposes a pragmatic framework to address identified gaps, thus aiding evidence-informed program design and implementation. The proposed Theory-Design-Implementation (TyDI) framework will support policymakers, program planners and implementers to address potential design and implementation failure, thus improving the fidelity of interventions.
Keywords: Implementation science; fidelity; frameworks; health policy; program planning.