We learned that the success or failure of implementation and diffusion across a health system does not depend primarily on the attributes of the innovation or the characteristics of the individual adopter. Rather it is due to the multiple and complex interactions between the enablers and frontline behaviors that arise in particular healthcare contexts and settings. In every case, four particular enablers were critical to success: 1. Vision, strategy and leadership: Every case had a clear vision which described the desired future around which all stakeholders could align; a well-defined strategy to execute the vision; and strong, effective leadership to build support for the vision and deliver the change. 2. A specific organization, program or initiative to promote diffusion: A special purpose program, organization or network of organizations was created or already in place to provide the impetus, coordination , resources and structures that facilitated diffusion of the innovation. 3. Funding for research, development and diffusion: Funding was made available to develop, pilot, evaluate, and/or scale-up diffusions. Initial funding generally came from the government, non-government organizations (NGOs) and other donors, sometimes combined with in-kind support from multiple parties. 4. Communication channels and networks across healthcare, other industries and the public: Effective communication and linkages across stakeholders helped to ensure that all were working towards a common goal and sharing insights on what as working well or not so well. Based on the evidence from the case studies, we believe that priority should be given to cultivating these four critical enablers. The absence of any one could have negative repercussions for the scale and pace of the take-up of the innovation.