Using network mathematics, economists at Harvard and the University of Notre Dame came up with a map that connects countries according to exports. The map, say the authors, is a step toward measuring how much poor countries must change to compete with rich ones. It reveals two hubs—Europe’s and North America’s high-tech products, and East Asia’s textile and electronics industries.

An apple exporter can move into oranges, but cell phones require capital and a structural overhaul. By making global patterns evident, the mapping technique may help developing countries strategize.