Abstract
Collaboration is a complex intervention with multiple components. It is both a process innovation and a product innovation, and it entails institutional development and change. These and other defining features implicate its contingencies. For example, collaboration is tailor made for needs, problems, and opportunities that manifest novelty, complexity, uncertainty, and interdependent relationships. Contingencies like these signal important constraints. For example, collaboration exacts steep transaction costs. Its potential benefits justify these costs and serve as incentives for its development. In fact, collaboration may be a defining feature of competent and optimal practice, and the failure to collaborate may be indicative of negligence and malpractice.