The health sector in Peru has undergone significant change in recent years, as state-administered systems are replaced with private and for-profit ones. Jim Yong Kim, A.D.A. Shakow and J. Bayona look at how the policy shift has gone forward with significant input from US planners, and bears close correspondence to the American private health care model. Such health reforms, they contend, are upheld with little attention to their empirical value as instruments to improve health outcomes in poor countries.