Global performance indicators (GPIs), such as ratings and rankings, permeate nearly every type of human activity, internationally and nationally, across public and private spheres. While some indicators aim to attract media readership or brand the creator's organization, others increasingly seek to influence political practices and policies. The Power of Global Performance Indicators goes beyond the basic questions of methodological validity explored by others to launch a fresh debate about power in the modern age, exploring the ultimate questions concerning real-world consequences of GPIs, both intended and unintended. From business regulation to terrorism, education to foreign aid, Kelley and Simmons demonstrate how GPIs provoke bureaucracies, shape policy agendas, and influence outputs through their influence of third parties such as donors and market actors and, potentially, even broader global authority structures.