Abstract
Project Extension for Community Healthcare Outcomes (Project ECHO), a telementoring intervention in which medical specialists share knowledge with medical generalists, has spread to many sites during its 22 years, reaching providers in nearly 200 countries. Based on our familiarity with the ECHO Institute, its practices, and our work with ECHO implementers at many sites, we explain the diffusion of this telehealth intervention in which medical specialists and generalist providers mentor each other in delivering specialty care to patients. We find the diffusion of Project ECHO to be well-accounted for by traditional factors including the perceived attributes of the ECHO model, the status of prominent ECHO adopters, and the inter-organizational environment within which the model arose. We also identify aspects of the ECHO model that have not always figured prominently in studies of diffusion but likely stimulated diffusion in this case. These include charismatic leadership, model elasticity, optional evaluation, and bounded elasticity. The Project ECHO experience can inform the decisions by proponents of other health care innovations to accelerate and broaden diffusion.