Across a range of policy domains, the landscape of global governance has grown increasingly crowded in recent decades. This is certainly true in development and crisis finance, where a “regime complex” of dozens of multilateral institutions overlap in both jurisdiction and membership. The resulting governance system features some competition among institutions, but also a substantial amount of cooperation in the form of co-financing arrangements. How these arrangements emerge and how they shape the performance of international financial institutions (IFIs) are the central questions of Richard Clark's Cooperative Complexity: The Next Level of Global Economic Governance.

To unpack the process of cofinancing, Clark draws a distinction between “political efficiency” and “economic efficiency.” The book's central claim is that co-financing is politically efficient: it serves the interests of powerful states that govern IFIs and the bureaucrats who staff them. But co-financing is often economically inefficient, degrading performance and development outcomes for the borrowing countries these institutions are designed to help. Clark supports these claims with a wide and impressive range of evidence: large-N observational studies, survey and laboratory experiments, elite interviews, analysis of internal International M