In this brief, the authors examine the creation, evolution, and expansion of Philadelphia's diverse provider model through the lens of this theory of change; they show that the beliefs and assumptions underlying the diverse provider model have been amended over time; and they illustrate how district and provider leaders have reshaped the model in response to political realities, the pressures of NCLB, and the continuing tensions between provider autonomy and strong district guidance. The authors argue that the story of Philadelphia's diverse provider model is not an account of market competition and school choice. Instead, it is an account of how the outsourcing of educational management functions has led to the development of a "cross-sectoral collaboration" between Philadelphia's public schools and a set of diverse providers. In this relationship, the district itself is positioned as the consumer of educational services as it strives to accelerate performance in low-performing schools and to take reforms to scale. (Contains 2 figures and 37 footnotes.)