Figure 1.

Conceptual model of relationships between implementation approaches, challenges and sources of support for implementation, and program successes. Implementation approaches are expected to achieve program success measures where they are evidence-based, contextually appropriate, and receive appropriate support to overcome challenges. The model combines elements of social support theory (Langford et al., 1997) to describe challenges and support, and implementation outcomes and long-term impacts (Proctor et al., 2011) to describe successes.