The Brookings Afghanistan Index presents numerical information on a range of security, economic, and political indicators of pertinence to the future of that country as well as the U.S. role within it. The Index was originally created in the early years of the 2000s, after a U.S.-led coalition overthrew the Taliban, pursued al-Qaida in the region, and sought to help Afghans build a state that could keep such extremist groups from regaining major footholds in the future. Our goal, then and now, is to present a wide enough array of information to gauge many aspects of the effort, without swamping a reader in so much detail or arcana as to obscure attention to the big-picture policy questions facing the United States and its allies and partners there.