TSA is responsible for ensuring air carriers’ compliance with regulatory requirements, including requirements reflected in TSA security directives. Related to watch-list matching, TSA outlines air carrier requirements in the No Fly List Procedures security directive, requiring domestic air carriers to conduct checks of passenger information against the No Fly List to identify individuals who should be precluded from boarding flights, and the Selectee List Procedures security directive, directing domestic air carriers to conduct checks of passenger information against the Selectee List to identify individuals who should receive enhanced screening (e.g., additional physical screening or a hand-search of carry-on baggage) before proceeding through the security checkpoint. Since 2002, TSA has issued numerous revisions to the No Fly and Selectee list security directives to strengthen and clarify requirements, and has issued guidance to assist air carriers in implementing their watch-list-matching processes. TSA conducts inspections of air carriers throughout the year as part of regular inspection cycles based on annual inspection plans to determine the extent to which air carriers are complying with TSA security requirements. These inspections are based on inspection guidelines known as PARIS prompts, which address a broad range of regulatory requirements (including airport perimeter security and cargo security, as well as screening of employees, baggage, and passengers). With respect to watch-list matching, inspection guidelines instruct inspectors regarding the aspects of air carrier watch-list matching that should be tested, such as whether air carriers are comparing the names of all passengers against names on the most current No Fly and Selectee lists in accordance with the procedures outlined in TSA’s security directives. TSA conducts watch-list-related inspections at air carriers’ corporate security offices (where policies and procedures are established on how watch-list matching is to be performed) and at airports (where policies and procedures for responding to a potential match are implemented). TSA’s principal security inspectors are responsible for conducting inspections at domestic air carriers’ corporate headquarters. These inspectors assess air carriers’ compliance with security requirements and provide direct oversight of air carriers’ implementation of and compliance with TSA-approved security programs. Field inspectors—known as transportation security inspectors—conduct watch-list-related inspections at airports. They are responsible for a multitude of TSA-related activities, including conducting inspections and investigations of airports and air carriers, monitoring compliance with applicable civil aviation security policies and regulations, resolving routine situations that may be encountered during the assessment of airport security, participating in testing of security systems in connection with compliance inspections, identifying when enforcement actions should be initiated, and providing input on the type of action and level of penalty commensurate with the nature and severity of a violation that is ultimately recommended to TSA’s Office of Chief Counsel. To further enhance commercial aviation security and as required by the Intelligence Reform and Terrorism Prevention Act of 2004, TSA is developing an advanced passenger prescreening program known as Secure Flight to assume from air carriers the function of matching passenger information against government-supplied terrorist watch lists for domestic, and ultimately international, flights. Through assumption of the watch-list-matching function from the air carriers, Secure Flight is intended to ensure a higher level of consistency than current air carrier watch-list matching and also help remedy possible misidentifications if a passenger’s name is similar to one found on a watch list. According to TSA plans, Secure Flight’s benefits, once the program becomes operational, will include eliminating inconsistencies in current air carrier watch-list matching decreasing the risk of unauthorized disclosure of sensitive watch-list information, reducing the number of individuals who are misidentified as being on the No Fly or Selectee lists, and integrating the redress process so that individuals are less likely to be improperly or unfairly delayed or prohibited from boarding an aircraft. TSA expects to begin assuming from air carriers the watch-list matching function for domestic flights in January 2009, and to assume this function from U.S. Customs and Border Protection for flights departing from and to the Unites States by fiscal year 2010. Since the terrorist attacks of September 11, 2001, TSA has imposed, through security directives, requirements for watch-list matching, which include identifying passengers with names similar to those on the No Fly and Selectee lists—a process TSA refers to as similar-name matching. Identifying passengers with names similar to those on the No Fly and Selectee lists is a critical component of watch-list matching because individuals may travel using abbreviated name forms or other variations of their names. Therefore, searching for only an exact match of the passenger’s name may not result in identifying all watch-listed individuals. Before undertaking revisions of the relevant security directives in 2008, TSA expected air carriers to conduct similar-name matching, but TSA’s security directives did not specify how many and what types of such name variations air carriers should compare. Consequently, the 14 air carriers we interviewed reported implementing varied approaches to similar-name matching. Some carriers reported comparing more name variations than others, and not every air carrier reported conducting similar-name comparisons. Air carriers that conduct only exact-name comparisons and carriers that conduct relatively limited similar-name comparisons are less effective in identifying watch-listed individuals who travel under name variations. Also, due to inconsistent air carrier processes, a passenger could be identified as a match to a watch-list record by one carrier and not by another, which results in uneven effectiveness of watch-list matching. Moreover, there have been incidents, based on information provided by TSA’s Office of Intelligence, of air carriers failing to identify potential matches by not successfully conducting similar-name matching. Generally, TSA had been aware that air carriers were not using equivalent processes to compare passenger names with names on the No Fly and Selectee lists. However, in early 2008 the significance of such differences was crystallized during the course of our review and following TSA’s special emphasis inspection of air carriers’ watch-list-matching capability. On the basis of these inspection results, in April 2008, TSA issued a revised security directive governing the use of the No Fly List to establish a baseline capability for similar-name matching to which all air carriers must conform. Also, TSA announced that it planned to similarly revise the Selectee List security directive to require the new baseline capability. According to TSA officials, the new baseline capability is intended to improve the effectiveness of watch-list matching, particularly for those air carriers that had been using less-thorough approaches for identifying similar-name matches and those air carriers that did not conduct any similar-name comparisons. However, because the baseline capability requires that air carriers compare only the types of name variations specified in the security directive, TSA officials noted that the new baseline established in the No Fly List security directive is not intended to address all possible types of name variations and related security vulnerabilities. Agency officials explained that based on their analysis of the No Fly and Selectee lists and interviews with intelligence community officials, the newly established baseline covers the types of name variations air carriers are most likely to encounter. TSA officials further stated that these revised requirements were a good interim solution because, among other reasons, they will strengthen security while not requiring air carriers to invest in significant modifications to their watch- list matching processes, given TSA’s expected implementation of Secure Flight beginning in 2009. If implemented as intended, Secure Flight is expected to better enable the use of passenger names and other identifying information to more accurately match passengers to the subjects of watch-list records. Until 2008, TSA had conducted limited testing of air carriers’ similar-name- matching capability, although the agency had undertaken various efforts to assess domestic air carriers’ compliance with watch-list matching requirements in the No Fly and Selectee list security directives. These efforts included a special emphasis assessment conducted in 2005 and regular inspections conducted in conjunction with annual inspection cycles. However, the 2005 special emphasis assessment focused on air carriers’ capability to prescreen passengers for exact-name matches with the No Fly List, but did not address the air carriers’ capability to conduct similar-name comparisons. Regarding inspections conducted as part of regular inspection cycles, TSA’s guidance establishes that regulatory requirements encompassing critical layers of security need intensive oversight, and that testing is the preferred method for validating compliance. However, before being revised in 2008, TSA’s inspection guidelines for watch-list-related inspections were broadly stated and did not specifically direct inspectors to test air carriers’ similar-name- matching capability. Moreover, TSA’s guidance provided no baseline criteria or standards regarding the number or types of such variations that must be assessed. Thus, although some TSA inspectors tested air carriers’ effectiveness in conducting similar-name matching, the inspectors did so at their own discretion and without specific evaluation criteria. In response to our inquiry, six of TSA’s nine principal security inspectors told us that their assessments during annual inspection cycles have not included examining air carriers’ capability to conduct certain basic types of similar-name comparisons. Also, in reviewing documentation of the results of the most recent inspection cycle (fiscal year 2007), we found that available records in TSA’s database made references to name- matching tests in only 6 of the 36 watch-list-related inspections that principal security inspectors conducted, and in only 55 of the 1,109 inspections that transportation security inspectors conducted. Without baseline criteria or standards for air carriers to follow in conducting similar-name comparisons, TSA has not had a uniform basis for assessing compliance. Further, without routinely and uniformly testing how effectively air carriers are conducting similar-name matching, TSA may not have had an accurate understanding of the quality of air carriers’ watch- list-matching processes. However, TSA began taking corrective actions during the course of our review and after it found deficiencies in the capability of air carriers to conduct similar-name matching during the January 2008 special emphasis inspection. More specifically, following the January 2008 inspection, TSA officials reported that TSA began working with individual air carriers to address identified deficiencies.