About 362 million travelers (citizens and non-citizens) entered the United States in FY2013, including about 102 million air passengers and crew, 18 million sea passengers and crew, and 242 million incoming land travelers. At the same time about 205,000 aliens were denied admission at ports of entry (POEs); and about 24,000 persons were arrested at POEs on outstanding criminal warrants. Within the Department of Homeland Security (DHS), U.S. Customs and Border Protection's (CBP) Office of Field Operations (OFO) is responsible for conducting immigration inspections at America's 329 POEs. About 21,464 CBP officers inspect travelers, agricultural products, and cargo at U.S. ports and abroad. Most foreign nationals visiting the United States also are subject to some form of screening prior to their arrival at a POE, including when they apply for a nonimmigrant visa or to enter through the Visa Waiver Program, and through CBP's screening of information provided by air and sea carriers. CBP's primary immigration enforcement mission at ports of entry is to confirm that travelers are eligible to enter the United States and to exclude inadmissible aliens. This mission is challenging because of the scope and complexity of immigration inflows: millions of travelers at hundreds of ports must be individually screened against dozens of rules governing who may or may not enter the country. Moreover, strict enforcement is in tension with a second core mission: to facilitate the flow of lawful travelers, who are the vast majority of persons seeking admission. A fundamental question for Congress and DHS is how to balance these competing concerns. The answer to this question varies across diverse geographic regions, different modes of travel, and in response to a constantly shifting landscape of potential threats and legal immigration flows. As part of this dual mission, and in support of its broader mandate to manage the U.S. immigration system, DHS also is responsible for implementing an electronic entry-exit system at POEs. Congress required DHS' predecessor to develop an entry-exit system beginning in 1996, but the implementation of a fully automated, biometric system has proven to be an elusive goal. This report reviews the legislative history of immigration inspections requirements and the entry-exit system. The report then describes the implementation of these provisions, including pre-travel screening, primary and secondary inspections, trusted traveler programs, outbound enforcement, and the entry-exit system. The final section of the report identifies a number of issues for Congress related to immigration admissions and enforcement at POEs. Controlling admissions is a core element of state sovereignty; but such control entails the opposing goals of: 1) preventing unlawful entries, while 2) facilitating legal flows. These policy goals are inherently in tension, as efforts to identify and interdict illegal entrants inevitably challenges, and may delay, the smooth flow of legitimate travelers. The Supreme Court has long held that Congress has absolute authority to control immigration by establishing rules for the admission, exclusion, and deportation of non-citizens. Some of the first federal laws, the so-called Aliens and Seditions Acts of 1798, authorized the President to arrest and/or deport any alien who represented a danger to the United States. And while Congress during most of the 19 th century generally favored open admissions to the sparsely populated country, a series of laws beginning in 1875 excluded several classes of aliens, including criminals and prostitutes, aliens from certain countries and regions, anarchists, communists, and aliens engaged in espionage, among others. Thus, while the specific issues in U.S. immigration law have evolved over time, a core policy goal has always been to prevent the entry of aliens who threaten U.S. interests . For the last several decades, these threats, or enforcement priorities, have fallen within three broad categories: Unauthorized immigration . Since 1980, the estimated unauthorized population in the United States has increased from about 2.5 million to about 11.7 million people. Between one-third and one-half of these aliens are believed to have entered lawfully through a POE and over-stayed their visas. An unknown proportion of illegal entrants also passed through POEs, either concealed in a vehicle or by using fraudulent documents. One enforcement priority at POEs, therefore, is to prevent these unlawful entries. Transnational crime . CBP officers performing immigration inspections are the primary line of defense against certain illegal flows, including in particular most illegal drug flows other than marijuana. Immigration inspectors also seek to arrest known smugglers and other criminals at POEs. International terrorism . National security concerns have loomed large in immigration policy in the years since the 2001 Al Qaeda attacks against the United States (the 9/11 attacks). All 19 of the 9/11 hijackers entered the United States legally through POEs, and constraining terrorist travel is now recognized as a critical defense against terrorist attacks within the United States. Yet while most people would agree that terrorists, criminals, and immigration violators are appropriate enforcement targets, no consensus exists about how to prioritize these threats because the likelihood of each type of illegal entry is unknown, and because the potential consequences of these threats are subjective and difficult to measure. The likelihood of each of these threats occurring also varies by geography and mode of entry. For example, certain types of illegal migrants may be more likely to travel by bus or car across the southern border, smugglers may favor other distribution routes, and terrorists may be likely to reach the United States by air and/or at northern border POEs. Threat actors also may seek to counter enforcement efforts by adapting their behavior to avoid such patterns. Enforcement must be balanced by a second overarching goal: the facilitation of legal flows. With international tourism directly accounting for over $200 billion in 2012 (almost 1% of U.S. gross domestic product), travel facilitation supports the U.S. economy. Smooth processing at POEs also streamlines travel for the tens of millions of U.S citizens returning from international trips each year, and may improve Americans' experiences abroad through reciprocal arrangements. In addition, immigration agents at POEs define visitors' first impressions of America and the U.S. government, and therefore play an important diplomatic role. Enforcement and travel facilitation are fundamentally in tension because efforts to identify and interdict unlawful travelers tend to impede the flow of the entire admissions queue, and efforts to expedite the line may increase the risk that an illicit traveler is overlooked. Thus, in addition to questions about how to prioritize diverse threats, Congress and DHS must decide how to balance enforcement and the facilitation of legitimate travel. Is it better to admit one illegal actor, or to delay the admission of 1,000 lawful travelers? How should Congress and DHS weigh the benefits of more robust enforcement against the costs to commerce, privacy and civil liberties, and related concerns? In an effort to reduce border wait times without compromising border security, CBP's response to these questions emphasizes "risk management." In general, risk management refers to a process for assessing the risks associated with potential threats and calibrating the enforcement response to the estimated gravity of the threat. In the case of immigration inspections, risk management involves screening travelers at multiple points in the immigration process to distinguish between low- and high-risk travelers. Low-risk travelers may be eligible for expedited admissions processing through the Visa Waiver Program and/or trusted traveler programs, while higher-risk travelers may be subject to more extensive secondary inspections. Unauthorized migrants at POEs may be subject to expedited removal and other types of immigration enforcement (see "The Immigration Inspections Process"). The procedures governing inspections of persons applying for admission are described in 8 C.F.R. Section 235, which derives its authority from Sections 101, 103, 215, 221, and 235 of the Immigration and National Act of 1952 (INA, P.L. 82-414), as amended. Under INA §215, in particular, both aliens and citizens are required to present appropriate entry documents, except as otherwise ordered by the President; and (pursuant to 8 C.F.R §235.1) to enter through designated ports of entry. INA §211 spells out additional documentary requirements for immigrant admissions. And INA §287 authorizes immigration officers, among other powers and pursuant to regulations, to interrogate any person believed to be an alien as to the person's right to enter or remain in the United States, and to arrest any alien attempting to enter the United States unlawfully. Prior to 2002, INA §103 made the Attorney General responsible for controlling U.S. borders and enforcing these laws. Pursuant to §§401- 403 of the Homeland Security Act of 2002 (HSA, P.L. 107-296 ), these responsibilities were transferred to DHS. The INA also authorizes the consular processing system as part of the visa issuance process, giving State Department consular officers sole authority to issue visas to aliens seeking admission to the United States. Section 428 of the HSA charged DHS with issuing regulations on visa issuances and authorized DHS personnel abroad to advise consular officers and to review and investigate visa applications; but the HSA left the State Department in charge of actual visa issuance (also see "Consular Reviews"). Historically, U.S. citizens and most citizens of Canada and Bermuda entering the United States by land or sea from the Western Hemisphere were exempted from certain document requirements. Following the 9/11 attacks, based on a recommendation by the National Commission on Terrorist Attacks upon the United States (the 9/11 Commission), Section 7209 of the Intelligence Reform and Terrorism Prevention Act of 2004 (IRTPA, P.L. 108-458 ) directed DHS, in consultation with the Department of State (DOS), to develop a plan to require a passport or other secure document(s) for all travel into the United States by U.S. citizens and others. The resulting plan, known as the Western Hemisphere Travel Initiative, requires adult land and sea travelers entering the United States from within the hemisphere to present a passport or other secure document. Section 110 of the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRIRA, P.L. 104-208 , Div. C) required the Attorney General, within two years of enactment (i.e., by September 30, 1998), to develop an automated entry and exit control system that would collect records of alien arrivals and departures and allow the Attorney General through online searches to match such arrivals and departures and thereby identify nonimmigrant aliens who remain in the United States beyond the periods of their visas (i.e., visa overstayers). The bill also required the Attorney General to annually report to Congress on the number of visa overstayers and their countries of origin. Congress has amended the system's requirements and deadlines on several occasions since then, including by adding an entry-exit requirement to legislation authorizing the Visa Waiver Program and by requiring the entry-exit system to include biometric technology and to be fully interoperable with DOS and Department of Justice (DOJ) databases. See the Appendix for a full list of entry-exit legislation. Despite Congress's ongoing attention, however, the entry-exit system remains incompletely implemented (see "Entry-Exit System: Implementation"). With the increased focus after 9/11 on national security during immigration screening, Congress has taken steps to ensure that DHS also focuses on travel facilitation. Section 302(b)(1) of the Enhanced Border Security and Visa Entry Reform Act of 2001 (EBSVERA, P.L. 107-173 ), for example, directed the departments to "utilize technologies that facilitate the lawful and efficient cross-border movement of commerce and persons without compromising the safety and security of the United States." In addition, §7209(k) of the IRTPA described congressional findings that "expediting the travel of previously screened and known travelers across the borders of the United States should be a high priority," including because it "can permit inspectors to better focus on terrorists attempting to enter the United States." The section directs DHS to develop and implement a registered traveler program for this purpose (see "Trusted Traveler Programs"). IRTPA §7210 also amended INA §235A to require DHS to add 25 preinspection stations (up from 5 required under IIRIRA) and to locate such stations at locations that "would most effectively facilitate the travel of admissible aliens" in addition to reducing the arrival of inadmissible aliens, as in the original language (see "Preclearance"). Travelers seeking to enter the United States go through one to three steps in the immigration inspection process. In the first step, prior to travel, most travelers who are not U.S. citizens or legal permanent residents (LPRs) must apply for permission to enter the United States, by obtaining a visa at a U.S. consulate abroad or through the Visa Waiver Program. Air travelers are subject to additional screening prior to arrival (see "Pre-Travel Screening"). Second, all arriving travelers are subject to inspection (or preclearance) by a CBP officer prior to entering the United States (see "Primary Inspections"). Third, some passengers also may be selected through risk-based screening or at random for more intensive scrutiny (see "Secondary Inspections and Immigration Enforcement"). Participants in CBP's trusted traveler programs volunteer for additional screening in advance and thereby become eligible for expedited processing at POEs (see "Trusted Traveler Programs"). Most foreign nationals seeking to enter the United States must get permission to do so prior to travel, and are subject to pre-travel screening. With the exception of U.S. LPRs, certain Canadian citizens, and certain residents of Caribbean islands other than Cuba, foreign nationals seeking admission to the United States must apply in advance for a nonimmigrant visa at a U.S. consulate abroad (see "Consular Reviews"), or in certain cases through an on-line process for permission to participate in the U.S. Visa Waiver Program (see "Visa Waiver Program"). Air passengers are subject to further screening at several points during the lead-up to their U.S.-bound flights (see "Air Passenger Screening"). Before applying for admission at a U.S. port of entry, aliens seeking to visit the United States generally must obtain a visa at a U.S. consulate abroad. Visa applicants are required to submit biographic and biometric data, and usually must participate in an in-person interview. Applicants also may be subject to physical and mental examinations. Consular reviews are designed to ensure that aliens do not receive a visa to visit the United States if they are inadmissible for any of the reasons identified in INA §212, including health-related grounds, criminal history, security and terrorist concerns, indigence (likely to become a public charge), seeking to work without proper labor certification, ineligibility for citizenship, and certain previous immigration violations. As part of the visa application process, DOS consular officers use the Consular Consolidated Database (CCD) to screen visa applicants. The CCD is a database of over 100 million visa and passport case records and 75 million photographs from 25 different DOS systems. The CCD links automatically to the Consular Lookout and Support System (CLASS) database, which consular officers use to identify visa applicants on security watchlists or with other derogatory information, and to the Arrival and Departure Information System (ADIS) and the Automated Biometric Identification System (IDENT), which CBP officers use to screen arriving travelers at POEs (see "Text Box: Select Immigration Inspections Databases and Systems"). Consular officers refer high risk cases to DHS and other law enforcement agencies for Security Advisory Opinions (SAOs). At certain consulates, the review process is further supplemented by the DHS Immigration and Customs Enforcement (ICE) Visa Security Program (VSP). Under this program, special agents at U.S. Immigration and Customs Enforcement (ICE) headquarters and in 20 high-risk consulates work with consular officers to examine visa applications for fraud, initiate investigations, coordinate with local law enforcement partners, and provide training and advice. The VSP Security Advisory Opinion Unit works with other law enforcement and intelligence agencies to provide a coordinated response when consular officers seek an SAO about a high risk case. The Visa Waiver Program (VWP) allows nationals from certain countries to enter the United States as temporary visitors for business or pleasure without obtaining a visa from a U.S. consulate abroad. Thus, the program is designed to facilitate travel and tourism from low-risk countries, while also fostering positive relations with such countries, and holding down consular operating costs. In FY2013, there were over 19 million visitors who entered the United States under the VWP program, constituting 40% of overseas visitors. Some Members of Congress have raised concerns that the VWP may weaken security because travelers are not required to provide biometric data when applying for admission through the program and are exempted from consular reviews. In addition, some people see the program as vulnerable to visa overstays since the entry-exit system has not been fully implemented (see "Entry-Exit System: Implementation"). On the other hand, aliens seeking admission under the VWP are required to submit biographic information and respond to eligibility questions through an on-line Electronic System for Travel Authorization (ESTA). Upon receipt of an ESTA application, CBP screens applicants' data against TECS and the Automated Targeting System. And aliens authorized for travel under the VWP must provide biometric data during primary inspection at a POE prior to entering the United States. The program also may enhance U.S. security because partner countries must meet specified document security and information-sharing requirements, and it benefits U.S. visitors to VWP countries because they receive reciprocal visa-free travel benefits. CBP conducts additional pre-travel screening of all persons (including U.S. citizens) seeking to travel to the United States by air. Upon a traveler's purchase of an airline ticket, commercial airlines are required to make Passenger Name Record (PNR) systems and data available to CBP up to 72 hours in advance of travel. When passengers check in for international flights to the United States, carriers are required to transmit passenger and crew manifests to CBP prior to securing aircraft doors before departure. Biographic traveler data (passport and travel itinerary information) is submitted to the Advance Passenger Information System (APIS). Passenger PNR and APIS data (as well as visa and ESTA data) are forwarded to CBP's National Targeting Center (NTC), where they are vetted against intelligence and law enforcement databases, including the consolidated terrorist watchlist and Interpol's lost and stolen passport list. Data are matched against targeting rules through the ATS to identify risky travelers. The NTC may issue a no-board recommendation to air carriers, and/or flag travelers for a secondary inspection upon arrival at a U.S. POE. The NTC issued 3,181 no-board recommendations in FY2011; it issued 4,199 no-board recommendations in FY2012, and 5,378 no-board recommendations in FY2013. Under the Immigration Advisory Program (IAP) program, created in 2004, CBP officers also are posted at 11 international airports in 9 partner countries. IAP officers review documents, conduct interviews, and identify high-risk travelers. They do not have enforcement authority, but may recommend that air carriers not board certain passengers for U.S.-bound flights, flag passengers for secondary inspection upon arrival, and notify host-state law enforcement agencies of suspected criminal violations. Building upon the IAP concept, CBP launched the Joint Security Program (JSP) in 2009. Currently operational in Mexico City and Panama City, the JSP performs similar functions as the IAP, but also addresses travelers on international flights not bound to or from the United States. The IAP and JSP issued 2,890 no-board recommendations in FY2011, 2,505 no-board recommendations in FY2012, and 3,501 no-board recommendations in FY2013. As of November 22, 2013, the IAP and JSP had made a total of 19,998 no-board recommendations since the IAP's inception in 2004. CBP officers at ports of entry interview arriving travelers and check their travel documents to determine whether the person is admissible to the United States. Basic biographic information (e.g., name, travel document number, date and location of arrival) for all travelers (including U.S. citizens) is collected and stored within TECS. Arriving travelers are subject to certain immigration, criminal, and national security background checks through the TECS system and the ATS, which identify certain travelers to be selected for secondary inspection. In general, these primary inspection activities have become far more intensive during the post-9/11 period. For example, whereas CBP historically examined drivers' documents at land POEs but did not consistently examine passenger documents, since 2010 CBP has inspected documents for 100% of land travelers. And whereas only 5% of land travelers were subject to law enforcement database queries in FY2005, 97% of land travelers were subject to such queries in FY2013. Southern border inspection protocols have focused in particular on evolving threats related to drug trafficking organizations, smugglers, and unauthorized immigrants. Travelers are also validated against visa or visa waiver program records (for non-citizens) and against the APIS database (for all air travelers). Non-citizens arriving at air and sea ports are required to provide biometric data (fingerprints and digital photographs), which are added to the IDENT database and vetted against additional biometric databases (see "Text Box: Select Immigration Inspections Databases and Systems"). Travelers determined by the CBP officer to be admissible are allowed to enter the United States, though they may be subject to a separate customs and/or agricultural inspection. Travelers suspected for any reason of being inadmissible, including because of high ATS scores or derogatory information in the TECS system, are referred to secondary inspection for additional screening and/or a more thorough interview (see "Secondary Inspection"). Travelers from 15 airports in Canada, Ireland, the Bahamas, Bermuda, and Aruba may be eligible to be pre-cleared by CBP officers based abroad. Preclearance (sometimes referred to as preinspection) includes the same document inspection, interview, and (as necessary) secondary inspection as normally occurs at a U.S. port of entry, including customs and agricultural screening. Preclearance officers at partner airports are unarmed and do not have law enforcement authority, but officers may refer people suspected of host-state criminal violations to partner country law enforcement agencies. Travelers arriving in the United States following a preclearance inspection may depart the aircraft directly into the arriving airport as they would from a domestic flight. CBP may initiate preclearance facilities at the request of a host government and pursuant to a formal agreement with such a government. Host governments are responsible for providing secure preclearance facilities, and CBP covers officer salaries (including certain overseas expenses). CBP views passenger preclearance programs as enhancing U.S. security and reducing deportation costs because such programs screen passengers earlier in the travel process, preventing the arrival of inadmissible travelers, as well as illegal weapons, agricultural products, etc., on U.S. soil. The programs also speed lawful travel by reducing congestion at U.S. airports, and they allow international travelers to take advantage of tighter U.S. connection times. In April 2013, DHS reached an agreement with the government of the United Arab Emirates (UAE) to set up a preclearance facility in the Abu Dhabi International Airport. Some Members of Congress have raised objections to the proposed Abu Dhabi program because no U.S. air carriers fly directly from Abu Dhabi to the United States, arguably giving the UAE-owned Etihad Airlines a competitive advantage over U.S.-owned carriers, and because UAE is not a signatory to the United Nations Refugee Convention. House appropriators included language in the House's FY2014 DHS Appropriations report to limit funding for preclearance operations in new locations unless an economic impact analysis of the new location on U.S. air carriers has been conducted and provided to the committee, among other conditions. Certain classes of nonimmigrants visiting the United States for a temporary period are issued an I-94 arrival/departure record upon admission. The I-94 record indicates the date of admission, class of admission (i.e., visa category), and visa expiration date. For travelers arriving at land ports, the I-94 consists of a paper form stapled to the foreign passport. Travelers are supposed to surrender the I-94 upon departure; and CBP may use I-94 receipts to track nonimmigrant exits and identify visa overstays. In practice, however, this system has proven difficult to implement, and paper I-94 receipts often are not collected from departing travelers. In 2013, CBP discontinued issuing paper I-94 forms for travelers arriving at air and sea ports. CBP now uses the APIS system and information collected by the State Department and by CBP officers at ports of entry to create electronic arrival/departure records for these travelers. In place of paper I-94 receipts for exiting air and sea travelers, CBP relies on carrier exit manifests (passenger lists) to confirm passenger departures (see "Entry-Exit System: Implementation"). Travelers who trigger an alarm in the ATS, who are the subject of certain derogatory information in TECS, or who arouse suspicion (through their behavior, responses to questions, or suspicious documents) during primary inspection may be referred for secondary inspection. A small sample of travelers at certain POEs also is randomly selected for secondary inspection (see "Random Compliance Examination (COMPEX) Program"). Travelers at land POEs who are required to obtain I-94 arrival/departure records (see "I-94 Arrival/Departure Records") also are automatically referred to secondary inspection, where I-94s are issued. In general, travelers selected for secondary inspection may be subject to a more extensive interview and/or a physical search, as well as being subject to vetting against additional databases. At land POEs, travelers selected for secondary inspection (in contrast with other land travelers) must provide fingerprints data to be vetted against IDENT and other biometric databases (see "Text Box: Select Immigration Inspections Databases and Systems"). Table 1 describes primary and secondary inspections by mode of entry for FY2005-FY2013. As Table 1 indicates, primary inspections at air and sea POEs fell slightly in FY2008 - FY2009, likely as a result of the global economic downturn, and inflows have increased since that time. Overall, inspections at air POEs increased about 19% in FY2005-FY2013, from about 86 million to about 102 million. Inspections at land ports fell more sharply, dropping every year FY2005-FY2011, before recovering slightly in FY2012-FY2013. At 242 million, land inspections in FY2013 were down 31% from the FY2005 total of 318 million. As a result of these trends, the total number of inspections fell from 420 million in FY2005 to 340 million in FY2011, before climbing back to 362 million in FY2013; and the proportion of all primary inspections occurring at land POEs fell from about 75% in FY2005 to about 67% in FY2013. As Table 1 also indicates, an increasing share of travelers was subject to secondary inspections during FY2005-FY2013. This trend exists across all three modes of entry, but was most pronounced at air POEs, where the proportion of travelers subject to secondary inspection increased from 2.0% in FY2005 to 6.4% in FY2010, before falling to 5.2% in FY2013 (5.3 million out of 102 million). At sea POEs, the proportion of travelers subject to secondary inspection increased from 0.49% in FY2007 (the first year for which data are available) to a high of 1.3% in FY2010, to 0.7% in FY2013. And at land POEs, the proportion of travelers subject to secondary inspection increased from 11.9% in FY2005 to about 14% in FY2010-FY2012, before falling back to 12.3% in FY2013. At land ports, the increase in the secondary inspection rate has been a function of the fall in total travelers at such ports, not an increase in the number of secondary inspections. A final observation about Table 1 is that the great majority of travelers inspected at POEs are determined to be eligible for admission . Overall, the annual rate at which persons inspected at POEs were admitted to the United States remained steady at between 99.94% and 99.95% in FY2005-FY2013. (Put another way, about 5 out of 10,000 people arriving at a POE are denied admission.) Approval rates were similar across air, sea, and land modes of entry. Pursuant to 8 C.F.R. 235.1, the burden of proof is on the traveler to demonstrate to a CBP officer at a POE that the traveler is a U.S. citizen or an admissible foreign national. In general, a person arriving at a POE who is determined to be ineligible for admission may be subject to similar sanctions as an unauthorized alien present in the United States, including four main outcomes: Withdrawal of application : Pursuant to INA §235(a)(4), a CBP officer may permit an alien applying for admission to withdraw his or her application for admission and depart immediately from the United States. An alien withdrawing an application is not subject to additional penalties (i.e., a withdrawal does not result in a period of inadmissibility), but a record of the withdrawal is added to the alien's file and may influence a future visa eligibility determination. Standard removal : In general, an alien at a POE whom CBP determines to be inadmissible under INA §212 may be subject to removal from the United States under INA §240. Pursuant to INA §239, a CBP officer may initiate removal proceedings by serving an alien with written notice, known as a notice to appear (NTA). Pursuant to §240, an alien facing such removal proceedings generally may appear before an immigration judge and may be eligible to seek certain types of discretionary relief from removal. An alien who is formally removed from the United States generally is ineligible for a visa (i.e., is inadmissible) for at least five years, and may be subject to criminal charges if he or she illegally reenters the United States. Expedited removal : Pursuant to INA §235(b), an alien arriving at a POE without documents or with fraudulent documents and who does not indicate a fear of persecution may be subject to "expedited removal" (ER). Under this provision, an alien may be formally removed by order of a CBP officer without appearing before an immigration judge and without being eligible for certain forms of relief. Aliens removed by ER are subject to the same penalties as aliens removed under INA §240. Criminal arrest : CBP may arrest individuals (including U.S. citizens) at land, sea, and air POEs on the basis of an outstanding federal, state, local, or tribal criminal warrant; in response to a suspected violation of federal immigration-related crimes; or in response to a suspected violation of other federal border-related crimes, including smuggling crimes. Table 2 describes selected immigration enforcement outcomes at ports of entry for FY2005-FY2013. As Table 2 indicates, there is no clear, sustained trend in three categories of interest: the overall number of aliens denied admission during this period has fluctuated between about 253,000 aliens in FY2005 and about 195,000 aliens in FY2012; the number of aliens issued a notice to appear (i.e., placed in standard removal proceedings) has fluctuated between about 15,000 aliens in FY2005 and about 24,000 aliens in FY2007 and FY2013 (consistently between 6 and 12% of aliens denied admission); and the number of persons arrested on criminal charges or warrants has fluctuated between about 23,000 and 28,000. Table 2 also reveals two apparent trends in enforcement outcomes at POEs. First, the number of aliens permitted to withdraw their applications for admission has fallen steadily from about 96,000 in FY2005 to about 52,000 in FY2013. According to CBP, this reduction is explained, at least in part, by a 2008 OFO directive permitting officers to exercise discretion in certain cases where applicants for admission are technically inadmissible due to a minor documentary deficiency, such as a recently expired passport or nonimmigrant visa. In such cases, aliens may be permitted to correct their documentation and reapply for admission at a later date and time without being required to formally withdraw an application for admission. Second, the number of aliens placed in expedited removal fell by about one-third between FY2005 and FY2009 (from about 55,000 to about 38,000), and has remained roughly flat since that time. It is not clear whether the initial drop in ER cases reflected a policy change, a change in the demographics of arriving aliens, or a statistical anomaly. Overall, the data in Table 2 do not appear to reflect a significant shift at POEs toward "high consequence" enforcement outcomes (i.e., an increase in the proportion of removable aliens facing criminal charges and/or formal removal). This trend stands in contrast to enforcement trends between ports of entry, where the Border Patrol has more systematically implemented CBP's Consequence Delivery System. CBP's Random Compliance Examination (COMPEX) program was established by the legacy U.S. Customs Service in 1999 to gather information about the effectiveness of the passenger inspections process, and CBP expanded the program after the creation of DHS to also encompass more general immigration and agricultural inspection activities. The program selects a random sample of vehicles and air passengers who would be cleared for admission to the United States during primary inspection, and subjects the sample to a detailed secondary examination. CBP counts violations detected in the sample of otherwise-cleared travelers to estimate the number of undetected violations. In FY2012, CBP reports that the COMPEX program was operational at 19 commercial airports representing over 80% of traveler volume, and at 105 land POEs representing over 94% of private vehicle volume. The program conducted over 640,000 random secondary inspections, including 184,000 air passengers and 456,000 vehicles at land POEs. Overall, a very small percentage of travelers in the sample were found to have committed a major violation. Theoretically, the COMPEX program offers a powerful tool to estimate illegal flows and CBP's effectiveness rate at POEs. Whereas developing accurate and reliable estimates of illegal flows and of the effectiveness of enforcement between POEs is notoriously difficult because of uncertainty about the number of unobserved inflows, detailed secondary inspections on a sample of inflows at POEs should produce an accurate count of violations within this group. And as long as the sample is statistically valid, CBP could use COMPEX results to estimate total illegal inflows and the apprehension rate at POEs. On the other hand, COMPEX is limited in some respects as a tool for describing illegal immigration flows. One limitation is that the program covers air passengers and personal vehicles at land POEs, but does not cover sea passengers, pedestrians at land POEs, or most cargo operations. Second, while a CBP officer may order the collection of biometric data as part of a COMPEX secondary inspection, such data is not collected systematically. As a result, while the program likely detects certain types of illegal migration through POEs (i.e., unauthorized immigrants hidden within passenger vehicles), COMPEX is not designed to detect certain other illegal inflows (i.e., unauthorized immigrants hidden within cargo containers or unauthorized immigrants using fraudulent documents or documents belonging to another person—not to mention flows of legal visitors who eventually overstay a nonimmigrant visa). A third limitation is that while COMPEX is designed to produce a statistically valid estimate of the overall number of POE violations, the program is not designed to measure violations within specific subcategories of flows, including the subcategory of illegal migration. In addition, while sampling at land POEs is based on the random assignment of cases through the TECS system, sampling at airports is based on the manual selection of cases by port managers and senior officers, which may introduce sample bias. Reportedly, COMPEX inspections also may be suspended at certain ports and certain times in order to speed processing times. For all of these reasons, it is not possible, based on COMPEX findings, to draw reliable inferences about total illegal inflows through POEs. A final concern about COMPEX is that information about the program has not been widely available. CBP considers such information law-enforcement sensitive, and does not publish information about COMPEX results or methodology; Congress has never held a public hearing on the program; and it has never been the subject of an extensive Government Accountability Office (GAO) study. These limitations make it difficult to evaluate the program or to weigh potential program reforms (also see "Illegal Migration through Ports of Entry"). Pursuant to §7209(k) of the IRTPA, CBP manages a number of "trusted traveler" programs that permit travelers to voluntarily provide detailed biometric and biographic data to CBP, and thereby to be eligible for expedited admission at POEs. Trusted traveler programs are designed to facilitate the admission of known, low-risk travelers and to strengthen security by focusing enforcement resources on unknown travelers (also see "Trusted Traveler Programs: Issues for Congress"). The main trusted traveler program is Global Entry, which is open to U.S. citizens and LPRs, Dutch citizens, South Korean citizens, and Mexican nationals. Canadian nationals also may receive Global Entry benefits by joining NEXUS (not an acronym; see "NEXUS"). In addition to meeting the nationality requirement, Global Entry applicants must not provide false or incomplete application information; have any previous criminal convictions or outstanding warrants; have any previous immigration violations; be the subject of an ongoing criminal investigation; be inadmissible to the United States; have any known or suspected terrorist connections; or be unable to satisfy CBP that they are low risk. Applicants are required to provide biometric data and participate in an in-person interview. Applicants are checked against a variety of national security and criminal databases during the initial application and upon each visit to the United States; and the entire trusted traveler list also is subject to regular re-checks against certain databases. In general, Global Entry members are eligible for expedited processing at participating POEs, which include 44 airports in the United States, Canada, Ireland, Guam, Northern Mariana Islands, and Puerto Rico. Instead of the normal primary and customs inspections, members present their machine-readable travel documents (via a card-swipe system), fingerprints (via a scanner), and customs declarations (via touchscreen) at an automated Global Entry kiosk. In most cases, the kiosk issues a receipt, and travelers may claim their bags and exit into the airport without further inspection. Global Entry members still may be selected for secondary inspection on the basis of derogatory information during the screening process or at random. NEXUS (not an acronym) is a jointly-managed U.S.-Canadian trusted traveler program. NEXUS applicants must meet similar eligibility requirements as those for Global Entry, and must be approved by both countries. As noted, NEXUS members automatically are eligible to use Global Entry kiosks and enjoy similar benefits at Global Entry locations. NEXUS members also receive a secure, Radio Frequency Identification (RFID) photo ID card that is Western Hemisphere Travel Initiative (WHTI) compliant, and that offers expedited processing through dedicated NEXUS travel lanes at 20 land POEs on the U.S.-Canadian border. The Secure Electronic Network for Travelers Rapid Inspection (SENTRI) program is a trusted traveler program that provides similar benefits at the U.S.-Mexico border as NEXUS provides at the U.S.-Canada border. SENTRI members receive a WHTI-compliant RFID card, which may be used at 11 land POEs. Unlike NEXUS, SENTRI is not jointly managed by the United States and Mexico. SENTRI members also must register their vehicles with the program, and may only use SENTRI lanes while driving registered vehicles. SENTRI applicants are subject to somewhat more stringent application requirements, and must provide original evidence of citizenship; original evidence of admissibility to the United States (for non-U.S. citizens); driver's license or state ID document; vehicle registration and proof of insurance or a notarized letter authorizing use of the vehicle if the SENTRI applicant is not the vehicle owner; evidence of employment or financial support; and evidence of residence. Table 3 summarizes cumulative trusted traveler program membership for FY2009-FY2013. As Table 3 indicates, all three programs have grown substantially during this period, with NEXUS and SENTRI growing five-fold and seven-fold, respectively, and Global Entry growing by a factor of 45. As of FY2013, Global Entry and NEXUS each counted over 900,000 members, while SENTRI included almost 360,000. Table 4 describes the annual number of travelers admitted through NEXUS and SENTRI lanes and Global Entry kiosks in FY2010-FY2013. As Table 4 indicates, trusted traveler flows have also increased during this period, though not as quickly as program membership, with Global Entry flows increasing seven-fold since FY2010, NEXUS flows doubling during this period, and SENTRI flows growing by about 50%. At certain land ports on the Southern border, travelers may be subject to screening and potential inspection as they depart the United States. Outbound enforcement is managed by the Outbound Programs Division within the Office of Field Operations. The division's mandate focuses on addressing violence in Mexico and the Mexico-United States drug trade by interdicting illegal currency, arms, and ammunition outflows. DHS reports that about 700 CBP officers participate in the outbound enforcement program. Table 5 describes annual seizures by the Outbound Programs Division for FY2009-FY2013. As Table 5 indicates, outbound enforcement seized a total of about 5,100 kilograms of illegal drugs during this period in 3,442 separate seizure incidents; $221 million worth of illegal currency exports; 8,210 illegal weapons, and about 12.1 million rounds of ammunition. Some experts view the number of southbound drug seizures—almost 3 per day in FY2013—as an indicator of the global nature of the market for illegal drugs, and of the United States' emerging role as a transshipment country for illegal drugs. At the same time, while seizure incidents have increased since FY2009, the average seizure size fell sharply in FY2013. Illegal currency and ammunition seizures are also down since FY2009 and FY2010, respectively. It is not clear whether the recent drop in illegal drug volume and the sustained drops in currency and ammunition seizures reflect changes in tactics by drug trafficking organizations or are statistical anomalies. Some people have argued that the United States should place greater emphasis on outbound enforcement to disrupt transnational criminal operations. According to this view, preventing U.S.-Mexico money and currency flows would eliminate the incentive for Mexico-U.S. drug flows, while also reducing criminal organizations' firepower. Outbound enforcement efforts confront a number of challenges, however. Laws restricting international currency transfers are notoriously difficult to enforce. Outbound enforcement also takes resources away from inbound inspections, so that increasing outbound screening may add to inbound delays or compromise inbound security. In addition, most outbound lanes are not equipped with inspection infrastructure, leaving officers exposed to the elements and to nearby traffic flows. Limited outbound lanes also mean that inspections may result in long waits for outbound travelers. Partly to address these concerns, outbound enforcement operations are normally short-term surges, followed by periods of reduced inspections. Yet some analysts have argued that sophisticated criminal organizations can defeat enforcement surges by monitoring outbound lanes, and by suspending high value outflows whenever a surge is underway. As noted elsewhere, Section 110 IIRIRA, as amended, requires DHS to implement an automatic, biometric entry-exit system that covers all non-citizen travelers into and out of the United States and that identifies visa overstayers (see "Entry-Exit System: Legislative Requirements"). Prior to 1997, the INS collected entry-exit data manually by obtaining paper copies of traveler's I-94 records (see "I-94 Arrival/Departure Records"), and an INS contractor manually keyed in data from the forms. This system was unreliable because paper forms were not consistently collected (particularly departure forms); forms were not timely provided to the contractor; and data input errors were widespread. INS initiated a pilot program in 1997 to further automate I-94 data collection by having airlines provide magnetic stripe I-94 arrival cards. Passengers passed the cards to INS agents at POEs during primary inspection. The automated system also proved problematic, however, because airlines were reluctant to participate, because departure cards still were not reliably collected, and because the system did not cover land travelers, among other shortcomings. With the passage of new entry-exit mandates in 2000-2001 (see "Entry-Exit system: Legislative Requirements") and the creation of the Department of Homeland Security (DHS) in 2002, the U.S. Visitor and Immigrant Status Indicator Technology (US-VISIT) program was established within DHS in 2004 to manage the entry-exit system. US-VISIT was renamed the Office of Biometric Identity Management (OBIM) in March 2013. CBP works with OBIM to collect and manage entry-exit data as described below. Entry-exit data are stored in two DHS databases: the Arrival and Departure Information System (ADIS) and the Automated Biometric Identification System (IDENT). ADIS includes biographic traveler identification data (name, date of birth, nationality, gender, passport number and country, U.S. visa number, and related information), arrival and departure information (POE and travel date), and a person-specific Fingerprint Identification Number System (FINS) identifier that allows ADIS to be cross-referenced with the IDENT system (see "Automated Biometric Identification System (IDENT)"). Although ADIS includes the FINS biometric identifier, ADIS is a biographic database because its records are populated by reading identity documents, rather than by capturing fingerprints or other physiological data directly from the traveler. As of September 30, 2013, ADIS included over 280 million unique records. IDENT includes biographic data (including name, aliases, date of birth, phone numbers, addresses, nationality, personal descriptive data), biometric identifiers (including fingerprints and photographs), and information about subjects' previous immigration enforcement histories (including previous immigration apprehensions and arrests). IDENT is a fully biometric database that makes use of fingerprint scanners and digital cameras to collect physical data directly from database subjects. As of September 30, 2013, IDENT included over 160 million unique records. The IDENT database initially was designed to capture only index fingerprints (i.e., two prints per person), and mainly was conceived of as a tool for tracking foreign visitors and identifying visa overstayers. With the creation of the Federal Bureau of Investigation's (FBI's) Integrated Automated Fingerprint Identification System (IAFIS) in 1999, the legacy Immigration and Naturalization Service (INS) and the FBI decided to integrate the IDENT and IAFIS databases to better identify criminal aliens. This integration eventually required the reconfiguration of IDENT as a ten-print system. It took several years to complete this transition, but by 2010 all CBP and Border Patrol locations had deployed fully integrated IDENT/IAFIS workstations. Particularly after the 9/11 attacks, the entry-exit system increasingly was seen as a national security tool for vetting arriving passengers. The USA PATRIOT Act required that the system be designed to permit background checks against relevant databases and identity verification throughout the visa application and admissions processes (see "Entry-Exit System: Legislative Requirements"). As of September 30, 2013, the IDENT security watchlist included 7.2 million people. Under US-VISIT/OBIM, the automated I-94 pilot program was discontinued, and entry data collection has been integrated into the immigration inspections process. In general, CBP officers collect entry data at ports of entry, and entry records automatically are added to the ADIS and (as appropriate) IDENT databases. Entry data collection has been enhanced in three main ways in the post-9/11 period. First, pursuant to the Visa Waiver Permanent Program Act ( P.L. 106-396 ) and the IRTPA ( P.L. 108-458 ), almost all travelers to the United States must present machine-readable passports or similarly secure travel documents to enter the country (see "Inspections for Admissions"). These standards are designed to improve biographic data collection by combatting document and identity fraud and reducing data input errors by automating information capture. Second, beginning in 2004, US-VISIT deployed integrated biometric workstations (i.e., fingerprint scanners) at POEs to facilitate biometric data collection. Workstations were deployed at 115 airports and 14 sea ports beginning in January 2004, expanded to the 50 busiest land POEs by the end of 2004, and have been operational at almost all POEs since December 2006. Third, under a final rule published in 2009, all non-U.S. citizens entering the United States are required to provide biometric data with the exceptions of Canadian nationals admitted as visitors, LPRs returning from cruises that begin and end in the United States or entering at land ports of entry, Mexican nationals with border crossing cards (BCCs), and travelers with other visas explicitly exempted from the program. In practice, the 2009 rule means that virtually all arriving non-citizens at air and seaports (other than U.S. LPRs returning from U.S.-based cruises) are required to provide biometric data during primary inspection. At land ports, arriving passengers only provide biometric data in secondary inspection (see "Secondary Inspections"). It bears emphasis that while a relatively small number of visa categories are exempted from the biometric requirement, these exemptions cover the majority of foreign visitors to the United States. In general, the United States does not have a history of collecting exit data from departing travelers. (In contrast, European Union member states, among other countries, for many years have required that people pass through passport control booths not only upon admission to the country, but also prior to their departure.) As a result, DHS and its predecessor agency have confronted inadequate port infrastructure and staffing to readily implement exit data collection as required by existing law. Since 2004, DHS has tested six exit data pilot programs and demonstration projects described below. Four of the programs have been described as problematic, and have been discontinued; but two programs involving biographic information sharing with air carriers and with the government of Canada have been described by DHS as successful, and are ongoing. Between January 2004 and May 2007, US-VISIT tested three different biometric exit technologies at 12 airports and 2 seaports under the so-called Increment 1B Pilot Program. At different airports and seaports, the program tested biometric collection kiosks located inside secure checkpoints, biometric collection mobile devices located in departure gate areas, and a combination of kiosks and mobile validator devices. DHS's evaluation of the program reportedly found that all three technologies and scenarios successfully captured biometric and biographic information, and that data collection required between 60 and 90 seconds per passenger. Based on a series of reports in 2005-2007, GAO concluded in 2007 that the Increment 1B air and sea pilot had "not been managed well"; and GAO recommended that DHS discontinue the program. In addition to concerns about program planning, oversight, and analysis of alternatives, GAO found that only 24% of travelers subject to US-VISIT requirements complied with the exit procedures, and that the program lacked enforcement measures and had not evaluated the effect of adding such measures. According to DHS's evaluation of the program, traveler compliance could be improved by integrating biometric data collection into the normal departure flow. The lack of exit infrastructure and the potential for congestion as a result of exit data collection are viewed as particularly problematic at land POEs. Between August 2005 and November 2006, DHS operated a land exit proof-of-concept demonstration project at five ports of entry on the southern and northern borders to test the use of Radio Frequency Identification (RFID) technology for tracking departures. Under the project, RFID tags were added to about 200,000 I-94 forms issued to nonimmigrant visitors. The goal of the project was to capture exit data with minimal new infrastructure or DHS staffing and without adding to border congestion. RFID technology is limited to biographic data, however. In addition, based on the demonstration project, RFID data collection proved unreliable, with successful data collection from RFID tags rates as low as 14% at some ports, and with scanners unable to consistently distinguish between RFID entries and exits. Thus, the conclusion drawn by GAO from the demonstration project was that RFID appears to be an inappropriate technology for exit data collection. Between May and July of 2009, US-VISIT worked with CBP and the Transportation Security Administration (TSA) to operate a pair of biometric air exit pilot programs. At the Detroit airport, CBP officers collected biometric data from aliens subject to US-VISIT at departure gates for selected international flights. Data was usually collected in aircraft jetways, between air carrier boarding pass collection and travelers' entry onto aircraft. Certain CBP officers were assigned to review travelers' documents to identify people subject to the program, who were then referred to additional officers for data collection. At the Atlanta airport, TSA officers screened travelers prior to their entry into the TSA security checkpoint to identify people subject to US-VISIT requirements. Such people were referred to a special line within the checkpoint, where other TSA officers collected their biometric data. DHS concluded that the pilot generally confirmed that biometric data may be collected from departing travelers. During the course of the program, about 500,000 travelers were screened by CBP and TSA officers; about 30,000 were identified as subject to US-VISIT; and only one traveler refused to provide his biometric data. Data collection only required a few seconds per passenger, and produced data of adequate quality for enrollment in IDENT. On the other hand, DHS also found that identifying travelers subject to US-VISIT requirements necessitated "extensive interaction" between screeners and travelers, that scaling up a program to cover all departures would greatly exceed available staffing capacity, that flight delays and related problems interfered with data collection, and that pilots and crew often boarded flights too early to be enrolled by CBP officers. Locating US-VISIT screening and data collection at TSA checkpoints also had an impact on a large number of U.S. citizens and passengers scheduled for domestic flights; and screening at TSA checkpoints arguably is less reliable than jetway screening when it comes to ensuring that people providing exit data actually leave the country. In addition to these specific concerns, DHS's more extensive review of its biometric exit testing concluded that a comprehensive biometric air exit system "faces enormous cost and logistical challenges," with funding requirements projected to total about $3 billion over a 10 year period. For these reasons, in 2010 DHS adopted a plan to focus in the near-term on enhanced biographic data collection and analysis to identify potential overstayers, and to invest in research and development of emerging biometric technology to be employed in a future exit system. In December 2009, US-VISIT and CBP initiated a pilot program to collect biometric data from exiting H-2A and H-2B temporary workers. The pilot deployed kiosks adapted for outdoor use, and applied to certain H-2A and H-2B workers who entered and exited through the San Luis, AZ and Douglas, AZ POEs. DHS reportedly plans to use information from the land exit pilot program to inform future land exit program planning, but CRS has not been able to locate additional information about the program. Since 2008, under the Advanced Passenger Information System (APIS) program, air and sea carriers are required to provide CBP with electronic copies of passenger and crew manifests prior to the departure of all international flights and voyages to or from the United States. For air carriers, such data must be provided prior to securing aircraft doors. CBP vets inbound passenger manifests against terrorist watchlist data, and CBP adds passenger arrival and departure data to the ADIS biographic database. According to DHS officials, air carrier compliance with APIS requirements has been close to 100% since 2010, and analysis of ADIS records allows DHS to identify air travelers who may have overstayed their visas (also see "Overstay Analysis"). While DHS apparently views the APIS program as a viable system for tracking air and sea exits, the system may be seen as not meeting the entry-exit system's legislative requirements in at least three ways. First, although air and sea carriers review passengers' passports prior to issuing a boarding pass, APIS does not include a mechanism to authenticate biometric data (i.e., APIS only collects biographic data). Second, relatedly, the APIS system is not designed to reliably insure that the same individual who checks in for a flight or voyage actually boards the aircraft or vessel. Third, although APIS provides CBP with electronic passenger manifest lists, the manifests are generated by carrier agents during the check-in process; such "manual" data may be less secure than data collected directly from travelers' passports (i.e., "machine-readable" data). On February 4, 2011, President Obama and Canadian Prime Minister Harper signed a joint declaration describing their shared visions for a common approach to perimeter security and economic competitiveness: the Beyond the Border agreement. Among other provisions, the agreement calls for the two countries to develop an integrated entry-exit system so that the record of a land entry into one country establishes an exit record from the other. The first phase of the program ran from September 2012 – January 2013, and included the exchange of biographic records for third country nationals and permanent residents (i.e., for persons other than U.S. or Canadian citizens) at four designated POEs. Canada was able to reconcile 94.5% of U.S. entries (i.e., Canadian exits) with Canadian immigration databases, and the United States was able to reconcile 97.4% of Canadian entries. Based on these results, the countries initiated phase 2 of the pilot program in June 2013, expanding data collection to all automated POEs on the U.S.-Canada border. DHS apparently views the U.S.-Canadian integrated entry-exit system as a promising approach for collecting exit data at the northern border. Under the current agreement, such information sharing will be limited to biographic data. DHS' ability to treat Canadian entry data as a reliable record of U.S. exits depends on both the organizational capacity of the Canada Border Services Agency (CBSA), and on a high level of trust and collaboration between CBSA and CBP. Within DHS, U.S. Immigration and Customs Enforcement's (ICE's) Overstay Analysis Unit identifies potential visa overstayers by matching ADIS arrival and departure records. ICE's Counterterrorism and Criminal Exploitation Unit (CTCEU) prioritizes certain overstay leads for further investigation. According to GAO's analysis of DHS data, DHS's enhanced biographic exit program reviewed a backlog of 1.6 million potential overstay records in 2011. About half of these cases (863,000) were found to have departed the United States or to have adjusted status. Out of the remaining records, along with 82,000 additional cases identified by CTCEU (i.e., a total of 839,000 records), DHS prioritized 1,901 (0.2% of overstayers; 0.1% of all cases initially reviewed) as possible national security or public safety risks. Further investigation of these high priority cases found that 1,013 individuals had departed the United States or adjusted to a lawful migration status, 9 individuals were arrested, and 481 individuals were the subject of ongoing ICE enforcement efforts as of March 2013, among other outcomes. The GAO also determined that about 1.2 million ADIS arrival records could not be matched to departure data, and raised questions about the quality of DHS's overstay data. Moreover, DHS and its predecessor agency have not provided Congress with statutorily required reports on visa overstays since 1994, though then-DHS Secretary Janet Napolitano testified in February 2013 that the department would report to Congress by the end of the year. News of humans infected with Ebola in West Africa has heightened concerns about the health screening of people arriving in the United States. Under current law, foreign nationals not already legally residing in the United States who wish to come to the United States generally must obtain a visa and submit to an inspection to be admitted. They must first meet a set of criteria specified in the Immigration and Nationality Act (INA) that determine whether they are eligible for admission. Moreover, they must not be deemed inadmissible according to specified grounds in the INA. One of the reasons why a foreign national might be deemed inadmissible is on health-related grounds. From an immigration standpoint, an outbreak of an infectious disease places substantial procedural and resource pressures on CBP, which is charged with screening all travelers at land, sea, and air ports of entry for admission. CBP works in conjunction with the Centers for Disease Control and Prevention (CDC) in HHS to monitor travelers for health-related risks and attempt to contain any diseases that may be spread by travelers coming from abroad. The CDC is the lead agency charged with protection against communicable diseases and is responsible for providing the technical instructions to CBP officers. CDC officials are not present at the border on a day-to-day basis, but there are quarantine stations located in a number of international airports and near a few land ports of entry. However, these stations constitute a small fraction of the 329 ports of entry operated by CBP. Even fully staffed quarantine stations are not in a position to perform routine health screening on all passengers crossing the border as a standard operating procedure. Rather than staffing all the POEs, the CDC, through their Division of Global Migration and Quarantine (DGMQ), trains CBP inspectors to watch for ill persons and items of public health concern. The CBP Inspector's Field Manual states that CBP officers are responsible for observing all travelers for obvious signs and symptoms of quarantinable and communicable diseases, such as (1) fever, which could be detected by a flushed complexion, shivering, or profuse sweating; (2) jaundice (unusual yellowing of skin and eyes); (3) respiratory problems, such as severe cough or difficulty breathing; (4) bleeding from the eyes, nose, gums, or ears or from wounds; and (5) unexplained weakness or paralysis. However, CBP officers are not medically trained or qualified to physically examine or diagnose illness among arriving travelers. The CDC also approves the physicians used at the POEs, and tests are performed in consultation with and in accordance with CDC guidance. CDC officials are to be stationed at the border during immigration emergencies and other periods when public health may be threatened. In the current context of the Ebola outbreak in West Africa, the Administration has established new screening procedures at five airports and requires all persons whose travel originated in Guinea, Liberia, and Sierra Leone to enter the United States through these five airports. The airports were selected because reportedly they represent more than 94% of the travelers coming from those three countries. When passengers arrive whose travel originated in one of the aforementioned countries—including U.S. citizens—they are escorted to a separate area for additional screening. The travelers fill out an extensive questionnaire, and have their temperature taken. Staff from the CDC is present at these airports to assist with the screening. Travelers without febrile illness or symptoms of Ebola will be monitored two times a day by state and local health departments for 21 days from their departure from West Africa. These travelers are also given a kit that contains a tracking log, a pictorial description of Ebola symptoms, a thermometer, and a wallet card with information on whom to contact if they have symptoms that can be presented to a health care provider if necessary. Those that have a fever or have symptoms consistent with Ebola will be immediately isolated. The completion of a more comprehensive entry-exit system has been a persistent subject of congressional concern. As discussed elsewhere, two limitations of the current system are that most people entering the United States by land POEs only provide biographic data (i.e., do not provide biometric data), and that DHS may not have a fully reliable system for overstay analysis (see "Entry-Exit System: Implementation"). DHS reportedly has made progress with respect to real-time overstay analysis, but did not publish estimated overstay rates that had been expected in 2013. In addition, even when DHS identifies potential visa overstayers in its dataset, the department has limited ability to track down and remove such overstayers. Arguably, the biggest questions about the entry-exit system concern the collection of exit data. No exit data are collected from persons leaving through southern border land ports; and data collection at other ports is limited to biographic data, is not always based on machine-readable data, and relies on information sharing with Canada and with air and sea carriers. DHS reportedly believes that the biographic information sharing generally meets its needs for purposes of exit tracking at an acceptable cost, and CBP has indicated, for purposes of immigration screening, that "[w]hile biometric information is growing in importance, the vast majority of data available for use at the POEs is biographical." At the same time, DHS has also argued that strengthening biographic data collection is a necessary precursor to biometric data collection, and views a biographic system as a desirable long-term goal for the entry-exit system. Members of Congress concerned with exit tracking may focus on the following questions: Are biographic data adequate for entry-exit tracking, or should biometric exit data collection be viewed as a priority? If biographic data are adequate, would an upgrade to machine-readable biographic data represent an improvement over the status quo? Is information-sharing using data provided by airlines and by Canada an acceptable model for exit data, of should DHS collect exit data directly? If information-sharing is acceptable, can a similar model be implemented on the U.S.-Mexico border , or does the Southern border require a different approach? If information-sharing is not acceptable, what additional infrastructure and personnel are required (and at what cost) for CBP to collect universal exit data? The 114 th Congress is considering legislation that would require the completion of the entry-exit system. The Secure Our Borders First Act of 2015 ( H.R. 399 ) would require the Secretary of Homeland Security to submit an implementation plan to execute a biometric exit data system. The bill would create a six-month pilot program to test the biometric exit system, which would precede the implementation of the roll out of the program. The bill sets forth staggered deadlines for full implementation of the exit system but would require full implementation of the system within five years of enactment. Discussions of immigration control and border security often focus on unauthorized flows between ports of entry; but unauthorized immigrants also enter through ports of entry, either illegally or by overstaying a nonimmigrant visa. Visa overstayers enter legally on temporary (nonimmigrant) visas but fail to depart before the visa expires. Unauthorized immigrants enter through ports of entry by using fraudulent documents (including counterfeit or altered documents, and legitimate documents that do not belong to them) or by evading inspection, for example by being hidden inside a vehicle. A potentially important question for Congress, particularly in light of the ongoing debate about immigration reform, is how much unauthorized immigration occurs through POEs ? A 2006 study estimated that 40-50% of unauthorized immigrants in the country at the time were visa overstayers, and this study remains the most recent reliable public estimate. In addition, interviews conducted with current and former unauthorized migrants in 2009 found that one out of four illegal entrants from Mexico had entered illegally through a port, either hidden in a vehicle or using borrowed or fraudulent documents, and that aliens attempting illegal entry through a POE were half as likely to be apprehended as those crossing between the ports. DHS has not published an estimate of the total number of visa overstayers in the United States or of the rate of illegal immigration through POEs, though the department reportedly plans to report on visa overstayers, as noted elsewhere. The department reportedly does not have plans to produce an estimate of illegal flows through POEs, and the COMPEX program is not currently designed to produce such an estimate (see "Random Compliance Examination (COMPEX) Program"). The program likely could be modified—primarily by increasing sample size—to produce such an estimate if Congress viewed such modifications as a priority, though CBP reportedly does not support such a change. Recent border security bills have targeted a greater share of resources to enforcement between ports of entry than to inspections and enforcement at POEs (see "Port of Entry Infrastructure and Personnel"). Some legislation in the 113 th Congress focused on enforcement between the ports. For example, S. 744 would require DHS to develop a strategy to achieve "effective control" of Border Patrol sectors between ports of entry, but does not establish goals or metrics for enforcement at the ports. On the other hand, the Border Security Results Act of 2013 ( H.R. 1417 ), as reported by the House Homeland Security Committee, would establish POE enforcement metrics, though it would not authorize new enforcement measures. One potential strategy for speeding migration flows while also enhancing border security is to add POE personnel and infrastructure. For any given volume of incoming travelers, both the flow rate (or "service level") and the time spent on inspections are a positive function of the number of CBP officers on duty and the number of active travel lanes. Conversely, according to a 2008 GAO report, infrastructure weaknesses increased the risk that vehicles could enter the United States without inspection; and staffing shortages contributed to morale problems, fatigue, lack of backup support, and safety issues, "increasing the potential that terrorists, inadmissible travelers, and illicit good could enter the country." GAO revisited these concerns in 2011 and reported that DHS was taking steps to address GAO's recommendations regarding staffing and infrastructure, but that CBP faced challenges in developing POE performance metrics. CBP's Workload staffing model identifies a need for 3,811 additional CBP officers at POEs in FY2014, and the Administration's FY2014 budget proposal included a request for 3,477 additional officers. To some extent, the Office of Field Operations (OFO) competes for resources with CBP's Border Patrol and with U.S. Immigration and Customs Enforcement (ICE). The Border Patrol has grown about three times faster than OFO in the post-9/11 period. Similarly, S. 744 , would direct CBP to more than double the number of Border Patrol agents on the southwest border, while only authorizing a 16% increase in OFO officers. Other bills in the 113 th Congress would augment POE staffing, however. Recent fiscal pressures have been a barrier to POE personnel increases. As mentioned, during the FY2014 budget process, the Administration proposed to hire 3,477 additional CBP officers (about half through increased appropriations and half through fee increases), but Congress approved a slower personnel growth, with half the proposed funding. Congress also authorized a pilot program in the FY2013 appropriations bill that permitted CBP to enter into public-private partnerships (PPPs) with certain localities and permitted the private sector to fund improvements in border facilities and port services, including by funding additional CBP officers and underwriting overtime hours. In its FY2014 budget, the Administration proposed expanding the pilot program by permitting CBP to accept donations to expand port operations. Approving the Administration's request, Congress extended the pilot program in the FY2014 DHS appropriations bill. The current pilot program permits CBP to accept donations to expand port operations, among other things. As noted elsewhere, one of CBP's primary tools for risk management at POEs is the use of trusted traveler programs, including Global Entry, NEXUS, and SENTRI (see "Trusted Traveler Programs"). Trusted traveler programs are designed to facilitate legal flows by allowing low-risk, known travelers to be exempted from certain screening and inspections and also to enhance security by allowing CBP officers to focus greater attention on higher-risk flows. The benefits of trusted traveler programs should increase with scale because moving more travelers into expedited lanes speeds overall processing times, and fewer unknown travelers mitigates the "needle in the haystack" challenge of enforcement at POEs. Thus, legislation in the 113 th Congress would promote membership in trusted trade programs. Congress and CBP confront certain obstacles to expanding trusted traveler programs, however. One of the main incentives CBP can offer trusted travelers is to reduce the likelihood of secondary inspections; but doing so may encourage mala fide actors to enroll in these programs to game the system. In addition, at land POEs, travelers only benefit from an expedited inspections process if they are also able to take advantage of dedicated NEXUS or SENTRI lanes (i.e., so that the entire queue is subject to expedited processing). But CBP has limited capacity to add and extend dedicated lanes because many ports are located in urban areas with limited space for expansion, though the agency has addressed this problem, to some extent, by using "active lane management" systems that adjust lane assignments based on real-time demand. Congress has enacted the following legislation concerning an entry-exit system: Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRIRA, P.L. 104-208 , Div. C). Section 110 required the Attorney General, within two years of enactment (i.e., by September 30, 1998), to develop an automated entry and exit control system that would collect records of alien arrivals and departures and allow the Attorney General through online searches to match such arrivals and departures and thereby identify nonimmigrant aliens who remain in the United States beyond the periods of their visas (i.e., visa overstayers). The bill also required the Attorney General to annually report to Congress on the number of visa overstayers and their countries of origin. P.L. 105-259 and P.L. 105-277 . These appropriations acts amended §110 of IIRIRA to extend the deadline for implementing the entry-exit system to October 15, 1998 for airports and seaports and to March 30, 2001 for land POEs. Immigration and Naturalization Service Data Management Improvement Act ( P.L. 106-215 ). The act amended IIRIRA §110 to describe the entry-exit system in greater detail; clarified that the system's mandate did not impose new documentary requirements on travelers to the United States; and imposed new deadlines of December 2003 for implementation of the entry-exit system at all U.S. airports and seaports, December 2004 for implementation of the system as the 50 busiest land POEs, and December 2005 for making data from the system available to immigration officers at all POEs. The act also authorized the Attorney General to make entry-exit system data available to other law enforcement officials for law enforcement purposes. Visa Waiver Permanent Program Act ( P.L. 106-396 ). Section 205 amended INA §217 to require the Attorney General (separate and apart from IIRIRA §110) to develop and implement a fully automated entry and exit control system to collect arrival and departure records for aliens traveling in and out of the United States under the Visa Waiver Program (also see "Visa Waiver Program"). Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA PATRIOT Act, P.L. 107-56 ). Section 411 encouraged the Attorney General to implement the IIRIRA entry-exit system "with all deliberate speed." The act directed the Attorney General, in the development of the system, to focus on the utilization of biometric technology and tamper-resistant documents; and it required that the system interface with law enforcement databases to identify individuals who pose a threat to national security. In addition, Section 403 required the Departments of Justice and State, working through the National Institute of Standards and Technology (NIST), to develop and certify a technology standard that can be used to verify the identity and check the backgrounds of persons applying for a U.S. visa or seeking admission at a POE. Enhanced Border Security and Visa Entry Reform Act of 2001 (EBSVERA, P.L. 107-173 ). Section 302 required the Attorney General and DOS to use the technology standard required to be developed under the PATRIOT Act at POEs and at consular posts abroad; to establish an arrival and departure database; and to make all alien admissibility security databases interoperable. Intelligence Reform and Terrorism Prevention Act of 2004 (IRTPA, P.L. 108-458 ). Among other provisions, Section 7208 reiterated Congress's finding that a biometric entry-exit system should be implemented as expeditiously as possible and required DHS to develop and report on a plan to accelerate the full implementation of such a system. The section also clarified that the entry-exit system shall include a requirement for the collection of biometric data for all categories of individuals required to provide such data, regardless of the POE. And it imposed a two year deadline for the development of a fully interoperable data system among relevant agencies within DOS, DHS, and DOJ. Implementing Recommendations of the 9/11 Commission Act of 2007 (9/11 Act, P.L. 110-53 ). Section 711 amended INA §217 (as previously amended by P.L. 106-396 ) to require DHS within one year to establish an exit system to record the departure of all air travelers participating in the Visa Waiver Program.

Summary: About 362 million travelers (citizens and non-citizens) entered the United States in FY2013, including about 102 million air passengers and crew, 18 million sea passengers and crew, and 242 million land travelers. At the same time about 205,000 aliens were denied admission at ports of entry (POEs); and about 24,000 persons were arrested at POEs on criminal warrants. Within the Department of Homeland Security (DHS), U.S. Customs and Border Protection's (CBP) Office of Field Operations (OFO) is responsible for conducting immigration inspections at America's 329 POEs. CBP's primary immigration enforcement mission at ports of entry is to confirm that travelers are eligible to enter the United States and to exclude inadmissible aliens. Yet strict enforcement is in tension with a second core mission: to facilitate the flow of lawful travelers, who are the vast majority of persons seeking admission. A fundamental question for Congress and DHS is how to balance these competing concerns. In general, DHS and CBP rely on "risk management" to strike this balance. One part of the risk management strategy is to conduct screening at multiple points in the immigration process, beginning well before travelers arrive at U.S. POEs. DHS and other departments involved in the inspections process use a number of screening tools to distinguish between known, low-risk travelers and lesser-known, higher-risk travelers. Low-risk travelers may be eligible for expedited admissions processing, while higher-risk travelers are usually subject to more extensive secondary inspections. As part of its dual mission and in support of its broader mandate to manage the U.S. immigration system, DHS also is responsible for implementing an electronic entry-exit system at POEs. Congress required DHS' predecessor to develop an entry-exit system beginning in 1996, but the implementation of a fully automated, biometric system has proven to be an elusive goal. The current system collects and stores biographic entry data (e.g., name, date of birth, travel history) from almost all non-citizens entering the United States, but only collects biometric data (e.g., fingerprints and digital photographs) from non-citizens entering at air or seaports, and from a subset of land travelers that excludes most Mexican and Canadian visitors. With respect to exit data, the current system relies on information sharing agreements with air and sea carriers and with Canada to collect biographic data from air and sea travelers and from certain non-citizens exiting through northern border land ports; but the system does not collect data from persons exiting by southern border land ports and does not collect any biometric exit data. Questions also have been raised about DHS' ability to use existing entry-exit data to identify and apprehend visa overstayers. The inspections process and entry-exit system continue to be perennial issues for Congress and a number of questions persist. Moreover, the scope of illegal migration through ports of entry, and how Congress and DHS can minimize such flows without unduly slowing legal travel continue to challenge policymakers and agency officials. The 114th Congress is considering legislation that would increase the number of port personnel as well as require the completion of the entry-exit system, a program that has been the subject of ongoing legislative activity since 1996, as summarized in the Appendix to this report.