When well-executed and well-supported, economic clusters can offer enormous potential for regional health, collaboration, and growth, and they have long been a dominant theme in economic development circles. An increasingly global economy has bolstered the importance of economic clusters, since having a clear advantage in an industry can attract talent, firms and capital from all over the world. And every locality wants self-reinforcing economic engines from which prosperity equitably flows to all corners. But many regions, states, and cities fail in their attempts to identify and grow such entities.