How can we evaluate the cost-effectiveness of health system strengthening? A platforms perspective

Abstract: Many health interventions depend on a complex system of human and capital infrastructure that is shared with other interventions, which we term service delivery ‘platforms’. These can take the form of healthcare facilities, hospitals, population-based health interventions and community services. Much health system strengthening (HSS) aims to improve the efficiency with which delivery platforms are used. This paper models the implications for cost-effectiveness analysis of interventions when service delivery relies on such shared platforms. The conventional approaches towards CEA are altered by relaxing the usual assumption that interventions are independent. Three types of investment are identified and modelled: (1) improving the quality of an existing shared platform that generates positive benefits across a range of existing interventions; (2) relaxing a capacity constraint for an existing shared platform that inhibits the optimization of existing interventions; (3) providing an entirely new shared platform that supports a number of existing or new interventions. The theoretical models are illustrated with stylized illustrations. The paper shows why it becomes essential to consider the portfolio of interventions that rely on a shared platform, and not just undertake a piecemeal analysis of individual interventions. The models demonstrate how to seek out the optimal trade-off between investing in platform improvements and spending on individual interventions. A platform perspective may lead to quite radical departures from conventional ranking of interventions.