"Since the September 11, 2001 attacks, the United States Government has made dramatic progress in information sharing -- particularly in sharing information once it is identified as terrorism information. However, the government continues to address the challenge of correlating disparate pieces of information that reside in various agency systems when the relevance of the information to terrorism is not readily apparent. The National Counterterrorism Center (NCTC) is the primary organization for analyzing and integrating all intelligence possessed or acquired by the government pertaining to terrorism and counterterrorism, excepting intelligence pertaining exclusively to domestic terrorism. To fulfill its statutory terrorism information responsibilities, NCTC must access and review datasets already lawfully collected by other government entities for national security purposes even if those datasets also include non-terrorism information. For example, certain information regarding visa applications, refugees, and international travelers may have potential connections to terrorism that are not readily apparent to the federal agency that maintains the data. It is often only through NCTC's access to terrorism information held by other government agencies that NCTC is able to correlate disparate information and uncover threats to the nation. In March 2012, Attorney General Eric Holder, Director of National Intelligence James R. Clapper, and NCTC Director Matthew G. Olsen signed updated guidelines designed to allow NCTC to more effectively analyze certain data already in the government's possession to better address terrorism-related threats, while at the same time increasing the protections for privacy and civil liberties. These guidelines were updated in response to issues identified by the White House, Congress, and Intelligence Community after the 2009 Fort Hood shooting and the Christmas Day 2009 bombing attempt. One such issue was the government's limited ability to query multiple federal datasets residing at different government agencies, and to correlate that information to proactively identify information that might relate to a potential attack. Similarly, the reviews noted that information that is not believed to be relevant could later be recognized as relevant based on subsequent events or information obtained at different points in time."
National Counterterrorism Center: http://nctc.gov/