Global health delivery and implementation research: a new frontier for global health.

The past century of global health interventions has been marked by stunning successes (eg, eradication of smallpox) and disappointing failures (eg, spread of malaria). Life expectancy has generally increased substantially across the globe, yet there remain large populations who suffer from eminently preventable and treatable diseases. Despite the existence of wellestablished, evidence-based interventions for many diseases, implementation and delivery of those interventions are not universal. Given the large disparity that exists between what is felt to be effective and what is currently being implemented in many parts of the world,1 there has been a recent increase in scholarly work dedicated to addressing the ‘‘knowledgeimplementation gap’’ in global health, especially in lowand middle-income countries (LMICs) and resource-constrained settings in high-income countries. This field of work, still nascent but rapidly maturing, is referred to as ‘‘global health delivery’’ and ‘‘implementation research,’’ and has substantial promise for contributing to significant gains in global health in the coming century. The term ‘‘global health delivery’’ at once poses a problem of hermeneutics. Are we referring to ‘‘global health’’ delivery–the delivery of a distinct entity called ‘‘global health’’–or are we referring instead to global ‘‘health delivery’’–the global application of a generic form of ‘‘health delivery’’? Whereas there is no consensus and several vocal proponents of