Prohibit, constrain, encourage, or purchase: how should we engage with the private health-care sector?

The private for-profit sector's prominence in health-care delivery, and concern about its failures to deliver social benefit, has driven a search for interventions to improve the sector's functioning. We review evidence for the effectiveness and limitations of such private sector interventions in low-income and middle-income countries. Few robust assessments are available, but some conclusions are possible. Prohibiting the private sector is very unlikely to succeed, and regulatory approaches face persistent challenges in many low-income and middle-income countries. Attention is therefore turning to interventions that encourage private providers to improve quality and coverage (while advancing their financial interests) such as social marketing, social franchising, vouchers, and contracting. However, evidence about the effect on clinical quality, coverage, equity, and cost-effectiveness is inadequate. Other challenges concern scalability and scope, indicating the limitations of such interventions as a basis for universal health coverage, though interventions can address focused problems on a restricted scale.