These cities address global poverty by giving people the chance to escape from precarious and harmful subsistence agriculture or dangerous urban slums. Charter cities let people move to a place with rules that provide security, economic opportunity, and improved quality of life. Charter cities also give leaders more options for improving governance and investors more opportunities to finance socially beneficial infrastructure projects. All it takes to grow a charter city is an unoccupied piece of land and a charter. The human, material, and financial resources needed to build a new city will follow, attracted by the chance to work together under the good rules that the charter specifies.
Like charter schools, they would be flexible, come with their own sets of rules, and give people access to tools they would otherwise lack. The model Romer references is Hong Kong, which enjoyed success after China leased it to Britain, eventually becoming a model for China's nationwide economic growth.