While national governments are already implementing various economic policies related to data flows in the real world, there is not yet a consensus on how economists should approach the topic. This column outlines a framework recently proposed by the T20 Task Force on Trade, Investment, and Globalization that classifies data flow policy into five categories and allows the appropriateness of policy from the viewpoint of economics to be discussed. As a result, it becomes possible to achieve policy harmonisation in some areas and to identify others where harmonisation cannot easily be achieved.