When the parts are greater than the whole: how understanding mechanisms can advance implementation research

Does the importance of context in implementation imply that generalizing about the effects of strategies is ultimately limited? Conceptual approaches for generalizing in the presence of significant contextual heterogeneity could advance implementation research but require novel perspectives.

Drawing from perspectives from Realist approaches, Pearl's transportability framework and philosophy of science, this paper outlines a mechanism-based approach to generalizing about the effects of implementation strategies. We suggest that understanding mechanisms creates a conceptual bridge between the effects of a strategy and the influence of the implementation context. Using directed acyclic graphs to represent the mechanisms of strategies, we show how conceptualizing mediators of overall effects offer a basis for considering the effects of context. Hence, theorizing and testing a mechanistic understanding enriches the ways in which we can consider how context could change those effects. Such an approach allows us to understand how a strategy works within a given implementation context, determine what information from new contexts are needed to infer across contexts, and if that information is available, what those effects would be - thereby advancing generalizing in implementation research. We consider particular implementation strategies (e.g., Community Adherence Groups and practice facilitation) as examples to illustrate generalizing into different contexts.

Mechanisms can help implementation research by simultaneously accommodating the importance of context as well as the imperative to generalize. A shift towards a mechanism-focused approach that goes beyond identifying barriers and facilitators can enhance the value of implementation research.