The Threat Index accounted for 20 percent of the total risk score, which was calculated by the intelligence community by assessing threat information for multiple years (generally, from 9/11 forward) for all candidate urban areas and categorizing urban areas into one of four tiers. Tier I included those at highest threat, relative to the other areas, and tier IV included those at lowest threat relative to the others. DHS's Office of Intelligence and Analysis performed this review and provided these threat assessments and corresponding threat values for each urban area. In contrast, for the 2006 grant cycle, DHS used total counts of threats and suspicious incidents and incorporated these into its model. The final threat assessments are approved by the intelligence community-the Federal Bureau of Investigation, Central Intelligence Agency, National Counter-Terrorism Center, and the Defense Intelligence Agency-along with the DHS Under Secretary for Intelligence & Analysis and the Secretary of DHS, according to DHS officials. (GAO, Homeland Security: DHS Improved its Risk-Based Grant Programs Allocation and Management Methods, But Measuring Programs Impact on National Capabilities Remains a Challenge, 11March08, p. 10)