The Homeland Security Department has been using the ATS for several years to perform risk assessments on the 120 million people who seek to enter the United States annually through all forms of travel; almost 90 million come by air. Federal officials call the ATS a critical tool that captures vital information from airline ticketing and other travel records, matches that information with law enforcement and intelligence data, and analyzes threats at the nation's borders to stop terrorist acts. But privacy advocates and civil-liberties groups have decried the ATS program as nothing more than a secretive data-mining and profiling technology that allows the government to collect and store highly personal information on travelers, including their habits and their contacts abroad. Some Democrats in Congress have also raised concerns about privacy and have questioned whether DHS is correcting any erroneous data in the system.
DHS traveler screening system under fire from privacy advocates, National Journal, September 28, 2007.