Page 1 GAO-19-298R Overstay Report

441 G St. N.W.

Washington, DC 20548

February 22, 2019

Congressional Committees

Department of Homeland Security: Review of the Fiscal Year 2017 Entry/Exit Overstay 

Report

Each year, millions of foreign visitors, or nonimmigrants, legally enter the United States on a 

temporary basis under specific nonimmigrant categories. They may travel to the United States 

with or as permitted, without a nonimmigrant visa and then enter the United States after 

admission at a U.S. port of entry for an authorized period of stay.1 Overstays are nonimmigrants 

who remain in the United States beyond the expiration of their authorized period of stay, 

regardless of whether they ultimately depart. The Department of Homeland Security (DHS) has

primary responsibility for identifying and addressing suspected overstays. According to DHS, 

identifying overstays is important for national security, public safety, and immigration 

enforcement. 

Within DHS, multiple components play a role in identifying and addressing suspected overstays. 

U.S. Customs and Border Protection (CBP) is tasked with, among other duties, inspecting all 

people seeking entry or applying for admission into the United States to determine their 

admissibility and compliance with U.S. law. CBP has an electronic process for identifying 

overstays who are suspected or known to have remained in the country beyond the expiration of 

their authorized period of stay. In addition, U.S. Immigration and Customs Enforcement (ICE) is 

the lead agency for enforcing immigration law in the interior of the United States and is primarily 

responsible for overstay enforcement. Further, U.S. Citizenship and Immigration Services 

(USCIS) receives, processes, and maintains documentation pertaining to a nonimmigrant’s 

immigration status, including the extension or change of status, and works with ICE to ensure 

proper adherence to U.S. immigration laws.

Federal law requires that DHS implement a program to collect data, for each fiscal year, 

regarding the total number of nonimmigrants who overstayed (i.e., remained in the United 

States after the expiration of their authorized period of stay) and report annually to Congress.

2

In January 2016, DHS issued its first report on estimated air and sea overstay rates that 

covered fiscal year 2015.3 Subsequently, DHS has issued reports covering fiscal years 2016 

and 2017. The reports provide data on expected departures and overstays by country for 

nonimmigrants who entered through an air or sea port of entry and who were expected to depart 

in a particular fiscal year.

 1

Certain individuals are allowed to seek admission without a visa, such as citizens of Canada, as well as participants 

in the Visa Waiver Program, through which nationals of certain countries may apply for admission to the United 

States as temporary visitors for business or pleasure without first obtaining a visa from a U.S. embassy or consulate 

abroad. See 8 U.S.C. § 1187; 8 C.F.R. §§ 212.1, 214.6(d), 217.1-217.7; 22 C.F.R. §§ 41.0-41.3.

2

See Visa Waiver Pilot Program Reauthorization Act of 1997, Pub. L. No. 105-173, § 2, 112 Stat. 56 (1998) 

(classified at 8 U.S.C. § 1376).

3

The nonimmigrant air and sea overstay population refers to those who entered the country through air and sea 

ports, rather than through land ports. CBP reports limited information on overstays who entered through land ports for 

reasons discussed later in this report.
Page 2 GAO-19-298R Overstay Report

The Explanatory Statement accompanying the Consolidated Appropriations Act, 2018 (2018 

Explanatory Statement), directed DHS to develop and report within 180 days after enactment 

(by September 2018) on a statistically-sound metric for measuring the total nonimmigrant air 

and sea overstay population in the United States at a given time.4 DHS responded to this 

directive through its Fiscal Year 2017 Entry/Exit Overstay Report.

5 The 2018 Explanatory 

Statement also included a provision for GAO to review DHS’s report and provide a preliminary 

briefing to the House and Senate Appropriations committees on its review within 90 days after 

DHS’s report is provided to the committees. This report transmits, in the form of the enclosed 

briefing, our assessment of DHS’s report and its findings that we provided to you electronically 

on December 19, 2018. The briefing examined how DHS identifies the total population of 

nonimmigrants who entered the United States through air and sea ports and for whom there is 

no evidence indicating an on-time departure. 

To examine how DHS identifies the total population of overstays who entered the United States 

through air and sea ports, we reviewed DHS's fiscal years 2015 through 2017 Entry/Exit

Overstay Reports, including the findings and methodology. In particular, we reviewed these 

three reports to determine any changes made to the methodology over time. In addition, we 

reviewed DHS documentation on how department officials determine the number of overstays, 

including standard operating procedures for developing the Entry/Exit Overstay Reports and an 

assessment of the methodology used to develop the fiscal year 2014 overstay report.6 Further, 

we reviewed prior GAO and DHS Office of Inspector General (OIG) reports on overstay 

identification and enforcement.

7 We also observed how CBP generates data for the overstay 

report by watching a CBP official extract data from DHS’s overstay data system. Finally, we 

interviewed CBP, ICE, and USCIS officials involved in the development of the overstay report to 

learn about their respective roles in generating the report, the data they provide and their data 

systems, the steps they take to ensure the data are reliable, and any challenges they encounter 

collecting and reporting the data. On the basis of the information we obtained from these 

agencies, we determined that the metric for measuring the air and sea overstay population in 

the United States is logically sound and DHS has taken steps to continually monitor and 

improve the quality of the data in the underlying databases. As a result, we present high-level 

summary results for purposes of illustration for the briefing, noting certain known limitations as 

appropriate.

We conducted this performance audit from October 2018 to February 2019 in accordance with 

generally accepted government auditing standards. Those standards require that we plan and 

 4

164 Cong. Rec. H2045, H2545 (daily ed. March 22, 2018), accompanying Pub. L. No. 115-141, 132 Stat. 348. The 

nonimmigrant air and sea overstay population refers to those who entered the country through air and sea ports, 

rather than through land ports. 

5

DHS, Fiscal Year 2017 Entry/Exit Overstay Report (Washington, D.C.: Aug. 7, 2018). 

6

DHS did not publish the fiscal year 2014 overstay report because of data reliability concerns. 

7

For example, see GAO, Border Security: DHS Has Made Progress in Planning for a Biometric Air Exit System and 

Reporting Overstays, but Challenges Remain, GAO-17-170 (Washington, D.C.: Feb. 27, 2017) and Overstay 

Enforcement: Additional Actions Needed to Assess DHS’s Data and Improve Planning for a Biometric Air Exit 

Program, GAO-13-683 (Washington, D.C., July 30, 2013). Also see DHS OIG, Progress Made, but CBP Faces 

Challenges Implementing a Biometric Capability to Track Air Passenger Departures Nationwide, OIG-18-80

(Washington, D.C.: Sept. 21, 2018) and DHS Tracking of Visa Overstays Is Hindered by Insufficient Technology, 

OIG-17-56 (Washington, D.C.: May 1, 2017). 
Page 3 GAO-19-298R Overstay Report

perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our 

findings and conclusions based on our audit objective. We believe that the evidence obtained 

provides a reasonable basis for our findings and conclusions based on our audit objective.

In summary, we found DHS has developed and implemented a metric to calculate the number 

and rate of air and sea overstays, which it has published annually beginning with its fiscal year 

2015 overstay report. CBP collects overstay data and develops the annual overstay report in 

collaboration with and using data from other DHS components, such as ICE and USCIS. As 

presented in the annual report, the overstay rate is an automated calculation based on the 

number of nonimmigrant admissions to the United States through air or sea ports of entry who 

did not depart in a fiscal year divided by the total number of expected departures for that fiscal 

year. CBP has also taken steps to improve its identification of overstays and the calculation of 

the overstay rate by, for example, automating the exchange of nonimmigrant data between 

CBP, ICE, and USCIS. Based on these and other improvements, CBP has included more 

complete data in the annual overstay report on more classes of admission over time, such as 

including foreign students beginning in fiscal year 2016. 

DHS’s fiscal year 2017 overstay report states that the report accounts for about 97 percent of all 

air and sea nonimmigrants expected to depart in fiscal year 2017. The remaining 3 percent 

pertained to classes of admission who are unlikely to overstay, according to DHS (e.g., foreign 

diplomats and flight crews). According to the fiscal year 2017 overstay report, there were about 

52.7 million nonimmigrant admissions to the United States through air or sea ports of entry who 

were expected to depart the country in fiscal year 2017. DHS identified about 702,000 overstays

during that time frame—1.33 percent of admissions. However, the overstay report does not 

include a metric for determining the total (i.e., cumulative) nonimmigrant air and sea overstay 

population in the United States at a given time as directed by the 2018 Explanatory Statement. 

Specifically, the report does not include air and sea overstays from prior years who may remain 

in the United States. CBP officials stated that they are considering including the total number of 

suspected air and sea overstays expected to depart since fiscal year 2015—the first year CBP 

determined overstay data to be reliable—in future reports. 

Although the overstay report identifies air and sea overstays, due to existing limitations in 

collecting departure data in the land environment, the 2017 overstay report provides limited 

departure and overstay information for land ports of entry, which DHS is required to collect and 

report by law.

8 When DHS uses data collected at land ports of entry, it is primarily to match 

records of certain travelers arriving into the United States by air and sea to records of those who

may have subsequently departed by land to Canada. However, DHS has efforts underway to 

collect biographic and biometric data on travelers arriving into and departing the United States 

at land ports to help develop a more comprehensive overstay estimate. For example, in fiscal 

year 2017, CBP began planning for a pilot test at the San Luis and Nogales, Arizona, ports of 

entry to demonstrate the feasibility of acquiring photos of all arriving and departing travelers and 

comparing those photos using facial recognition to photos in government databases. CBP 

officials stated that the pilot test for arriving travelers began at the San Luis Port of Entry in 

September 2018 and the Nogales Port of Entry in October 2018.

 8

The collection of departure information in the land environment is more difficult than in the air and sea environments 

due to the major physical, logistical, and operational obstacles involved with electronically collecting an individual’s 

biographic and biometric data.
Page 4 GAO-19-298R Overstay Report

Agency Comments

We provided a draft of this report to DHS for comment. DHS provided technical comments, 

which were incorporated as appropriate.

-------

We are sending copies of this report to the appropriate congressional committees, the Secretary 

of Homeland Security, and other interested parties. In addition, the report is available at no 

charge on the GAO website at http://www.gao.gov.

If you or your staff have any questions about this report, please contact me at (202) 512-8777 or 

GamblerR@GAO.gov. Contact points for our Offices of Congressional Relations and Public 

Affairs may be found on the last page of this report. GAO staff who made key contributions to 

this report include Adam Hoffman (Assistant Director), James Cook, Paul Hobart, Amanda 

Miller, Sasan J. “Jon” Najmi, Claire Peachey, and Khristi Wilkins. 

Rebecca Gambler

Director, Homeland Security and Justice

Enclosure
Page 5 GAO-19-298R Overstay Report

List of Committees

The Honorable Shelley Moore Capito

Chairman

The Honorable Jon Tester

Ranking Member

Subcommittee on Homeland Security

Committee on Appropriations

United States Senate

The Honorable Lucille Roybal-Allard

Chairwoman

The Honorable Chuck Fleischmann

Ranking Member

Subcommittee on Homeland Security

Committee on Appropriations

House of Representatives
Department of Homeland Security: Review of the 

2017 Entry/Exit Overstay Report

Information Provided to Staff of the Ho

Senate Appropriations Committe

For more information, contact: Rebecca Gambler (gamblerr@gao.gov)

Enclosure 
Contents

• Introduction• Legislative Language • GAO Objective• Scope and Methodology• Summary of Observations• Background• Observations• GAO Contacts
Introduction

• Each year, millions of foreign visitors, or nonimmigrants, legally enter the Unite

temporary basis under specific nonimmigrant categories. They may travel to thwith or, as permitted, without a nonimmigrant visa and then enter the United Sadmission at a U.S. port of entry for an authorized period of stay.1

• Overstays are nonimmigrants who remain in the United States beyond the exp

authorized period of stay, regardless of whether they ultimately depart.

• The Department of Homeland Security (DHS) has primary responsibility for ide

addressing suspected overstays. According to DHS, identifying overstays is im

security, public safety, and immigration enforcement.

1Certain individuals are allowed to seek admission without a visa, such as citizens of Canada, as well as participants in 

through which nationals of certain countries may apply for admission to the United States as temporary visitors for businobtaining a visa from a U.S. embassy or consulate abroad. See 8 U.S.C. § 1187; 8 C.F.R. §§ 212.1, 214.6(d), 217.1-21
Introduction (cont.)

• Within DHS, multiple components play a role in identifying and addressing sus

• U.S. Customs and Border Protection (CBP) is tasked with, among other d

people seeking entry or applying for admission into the United States to dadmissibility and compliance with U.S. law. CBP designates classes of no(generally aligned with the initial visa type) based on the form of admissiosuch as temporary workers and trainees, students, and temporary visitorpleasure. Since 2016, CBP has publicly reported the number of nonimmigthe United States through air and sea ports and were expected to depart year but did not do so by the end of their authorized period of stay (overslimited information on overstays who entered through land ports for reasoin this briefing.

• U.S. Immigration and Customs Enforcement (ICE) is the lead agency for 

immigration law in the interior of the United States and is primarily respon

enforcement. 

• U.S. Citizenship and Immigration Services (USCIS) receives, processes, 

documentation pertaining to a nonimmigrant’s immigration status, includichange of status, and works with ICE to ensure proper adherence to U.S

2The Department of State is responsible for receiving, vetting, and processing applications for immigration and tempora

States from abroad. 
Legislative Language

• The Explanatory Statement accompanying the Consolidated Appropriations Ac

Explanatory Statement), directed DHS to develop and report within 180 days aSeptember 2018) on a statistically-sound metric for measuring the total nonimoverstay population in the United States at a given time.3 The report should als

characteristics of suspected in-country overstays and detail how the Departmecollection and use of data sets necessary to develop a more comprehensive inoverstay estimate.4 DHS responded to this directive through its Fiscal Year 20

Overstay Report.5 Although the 2018 Explanatory Statement does not direct D

land overstay population, federal law does require DHS to collect data and annumber of overstays, regardless of the manner of lawful entry.6

• The 2018 Explanatory Statement included a provision for GAO to review this r

preliminary briefing to the House and Senate Appropriations Committees on itdays after DHS’s report is provided to the committees. 

3164 Cong. Rec. H2045, H2545 (daily ed. March 22, 2018), accompanying Pub. L. No. 115-141, 132 Stat. 348. The non

overstay population refers to those who entered the country through air and sea ports, rather than through land ports. 

4According to DHS, suspected in-country overstays have no departure records nor did they obtain an extension, or othe

protection, prior to the end of their authorized admission period. 

5DHS, Fiscal Year 2017 Entry/Exit Overstay Report (Washington, D.C.: Aug. 7, 2018). Throughout this briefing, we refer 

year 2017 overstay report.

6See Visa Waiver Pilot Program Reauthorization Act of 1997, Pub. L. No. 105-173, § 2, 112 Stat. 56 (1998) (classified a
GAO Objective

• This briefing examines how DHS identifies the total population of nonimmigran

United States through air and sea ports and for whom there is no evidence ind

departure. Specifically, it describes how DHS calculates and reports informatioof overstays, the findings of the fiscal year 2017 overstay report, and the air a

information not included in the report. This briefing also describes steps DHS departure information at land ports.
Scope and Methodology

• To address our objective, we reviewed:

• DHS's fiscal years 2015 through 2017 Entry/Exit Overstay Reports, includ

and methodology. In particular, we reviewed these three reports to determmade to the methodology over time. 

• DHS documentation on how department officials determine the number o

including standard operating procedures for developing the Entry/Exit Ov

• DHS’s Office of Administration Investment Analysis Office (IAO) draft revi

of the methodology used to develop the fiscal year 2014 overstay report publicly released due to data reliability concerns). IAO conducted this assrequest of CBP to review the reporting process, data systems and inputsand vetting processes used to develop overstay estimates. 

• Prior GAO and DHS Office of Inspector General (OIG) work on overstay 

enforcement.7

7For example, see GAO, Border Security: DHS Has Made Progress in Planning for a Biometric Air Exit System and Rep

Challenges Remain, GAO-17-170 (Washington, D.C.: Feb. 27, 2017); Overstay Enforcement: Additional Actions Neede

Improve Planning for a Biometric Air Exit Program, GAO-13-683 (Washington, D.C., July 30, 2013); and Overstay EnforMechanisms for Collecting, Assessing, and Sharing Data Could Strengthen DHS’s Efforts but Would Have Costs, GAO-Apr. 15, 2011). Also see DHS OIG, Progress Made, but CBP Faces Challenges Implementing a Biometric Capability to Departures Nationwide, OIG-18-80 (Washington, D.C.: Sept. 21, 2018) and DHS Tracking of Visa Overstays Is HindereOIG-17-56 (Washington, D.C.: May 1, 2017). 
Scope and Methodology (cont.)

• We also observed how CBP generates data for the overstay report by watchin

extract data from the system CBP uses to generate a list of suspected oversta

• We interviewed CBP, ICE, and USCIS officials involved in the development of 

to learn about their respective roles in generating the report, the data they prosystems, the steps they take to ensure the data are reliable, and any challeng

collecting and reporting the data. On the basis of the information we obtained agencies, we determined that the metric is logically sound and DHS has taken continually monitor and improve the quality of the data in the underlying databwe present high-level summary results for purposes of illustration for this briefknown limitations as appropriate.

8

8We did not assess the reliability of the underlying data systems or conduct an independent test of the data to ensure their reliability

13-683 for more information on the underlying data systems.
Summary of Observations on DHS’s Fiscal Year 201

Report• DHS has developed and implemented a metric to calculate the number and ra

overstays, which it has published annually beginning with its fiscal year 2015 oCBP collects overstay data and develops the annual overstay report in collabousing data from other DHS components, such as ICE and USCIS. CBP has alimprove its identification of overstays and the calculation of the overstay rate bautomating the exchange of nonimmigrant data between CBP, ICE, and USCI

• The fiscal year 2017 overstay report identified the number of air and sea overs

2017 (about 702,000 overstays out of about 52.7 million admissions—1.33 pe

• The overstay report does not include a metric for determining the total (i.e., cu

nonimmigrant air and sea overstay population in the United States at a given tthe 2018 Explanatory Statement. Specifically, the report does not include air afrom prior years who may remain in the United States. CBP officials stated thaconsidering including the total number of suspected overstays expected to deyear 2015 in future reports. Further, the overstay report includes limited informnonimmigrants who were admitted into the United States at land ports. 

• DHS has efforts underway to collect biographic and biometric data on traveler

United States at land ports to help develop a more comprehensive overstay es
Background—Nonimmigrant Admissions and Over

• Generally, prospective nonimmigrants seeking to visit the United States do so throu

• Those eligible for the Visa Waiver Program apply online for authorization to tra

States under the program before commencing travel to the United States from 

origin. 

• Those not eligible for the Visa Waiver Program and not otherwise exempt from 

requirement must obtain a visa from a U.S. consular office overseas.

• CBP receives passenger manifests from commercial air and sea carriers and privat

arrivals and departures from the United States. 

• Upon arriving at a port of entry, nonimmigrant travelers must undergo inspection by 

determine whether or not they may be admitted into the United States for an authorCBP officers are to collect biographic information (such as name and date of birth) applying for admission and are to confirm the accuracy of the biographic manifest dcarriers. 

• If CBP determines a nonimmigrant traveler is admissible, it grants the individual an 

stay. This period may be for a specific length of time, which CBP designates by ass“admit until” date, or for as long as the nonimmigrant maintains compliance with the program or activity, the duration of which may be variable. For example, a foreign seligible to remain in the United States for “duration of status,” meaning as long as thnormal progress toward completion of their educational objective, including by beinattending classes for an approved course of study (except during any normal breakor engaging in authorized practical training following completion of studies.
Background—Nonimmigrant Admissions and Over

• Overstays are nonimmigrants who remain in the United States beyond the expi

authorized period of stay by: (1) failing to depart by the status expiration date oqualifying activity (plus any time permitted for departure) without first obtaining other valid immigration status or protection, or (2) violating the terms and condinonimmigrant status at any point during their stay. 

• If a nonimmigrant would like to stay in the country under his or her current statu

previously authorized, he or she must file an application for extension of status 

the admission period expires. Certain nonimmigrants cannot apply for an extenparticipants in the Visa Waiver Program and those who fail to maintain status dviolating their terms of admission.
Background—DHS Identification and Reporting of O

• Federal law requires that DHS implement a program to collect data, for each f

regarding the total number of nonimmigrants who overstayed (i.e., remained in after the expiration of their authorized period of stay) and report annually to Conumerical estimates of the number of overstays from each country in each noclassification.

9

• In January 2016, DHS issued its first report on estimated air and sea overstay 

fiscal year 2015. Subsequently, DHS has issued reports covering fiscal years reports provide data on expected departures and overstays, by country, for noentered through an air or sea port of entry and who were expected to depart in year.

• DHS identifies two types of overstays:

• Suspected in-country overstays refer to individuals for whom no departur

recorded.

• Out-of-country overstays refer to individuals whose departure was record

authorized period of admission expired.

9See Visa Waiver Pilot Program Reauthorization Act of 1997, Pub. L. No. 105-173, § 2, 112 Stat. 56 (1998) (classified a
Background—DHS Identification and Reporting of O

(cont.)

• CBP has an electronic process for identifying overstays who are suspected o

remained in the country beyond the expiration of their authorized period of stasuspected overstay is automatically flagged in CBP’s Arrival and Departure In

(ADIS) when there is no record of the individual’s departure.10 The suspected 

checked against other DHS immigration databases to determine whether the an extension or other valid immigration status or protection and thus is not a p

CBP conducts this matching of entry, exit, and change of status information pbiographic data, which is supplemented with biometric data.11

10ADIS is a person-centric system that matches nonimmigrant biographic information (such as name and date of birth) 

to determine whether nonimmigrants departed the country according to their terms of admission.

11In February 2017, we reported that DHS had made progress developing a biometric exit capability to collect biometric 

from individuals exiting the United States. We found that CBP had tested biometric exit capabilities, but that challenges 

Pilots underway to collect biometric and biographic information for nonimmigrants departing the United States at land plater in this briefing. 
Background—DHS Identification and Reporting of O

(cont.)

• CBP relies on third-party departure data, such as commercial carrier passeng

confirm an individual’s exit from the country. CBP receives commercial passen

biographical data directly from air and sea carriers through the Advance PasseSystem (APIS) prior to the passenger and crew’s arrival in or departure from tCarriers are required to provide specific biographic data, including name and pand carriers are subject to fines for missing or inaccurate data. 

• APIS then shares the data with ADIS, which works as a central repository and 

designed to determine who has complied with the terms of admission and who 

• In addition to arrival and departure information, ADIS receives other DHS data 

USCIS relevant to whether a person is lawfully present in the United States. Tinformation on the primary DHS databases used for determining suspected ovextensions, changes, or adjustments of status are necessary steps to determi

person is an overstay who remained beyond the authorized period of admissio

person traveling to the United States for business or pleasure may be admittemonth authorized period of stay, and then the individual may subsequently apfrom USCIS an extension of up to 6 months.
Background—DHS Identification and Reporting of O

(cont.)

Table 1: Selected Department of Homeland Security (DHS) Databases Used for Identifyin

Source: GAO analysis of DHS information. | GAO-19-298R

Database DHS component 

responsible for managing database

Information maintained in the database r

Arrival and Departure Information System (ADIS)

U.S. Customs and Border Protection

Nonimmigrant arrival and departure informa

individual may remain in the United States, information (e.g., the address where the indUnited States).

Automated Biometric Identification System (IDENT)

Office of Biometric Identity Management

Biometric information collected from nonimmthe United States (i.e., fingerprints and phot

Student and Exchange Visitor Information System (SEVIS)

U.S. Immigration and Customs Enforcement

Information about nonimmigrant foreign stu

study and exchange visitors in the United S

Computer-Linked Application Information Management System 3 (CLAIMS)

U.S. Citizenship and Immigration Services 

Status of foreign nationals’ petitions for exte

immigration status (e.g., to convert from a tmaintains data on applications to extend or and applications for work authorization or fo

status.
Background—Prior GAO Work

• In April 2011, we found that DHS’s efforts to identify and report on overstays were hin

data, and we identified various challenges to DHS’s efforts to identify potential overst

DHS has taken action to strengthen its processes for reviewing records to identify potdiscussed later in this briefing. 

• In July 2013, we reported on the extent to which DHS’s changes in its systems or pro

ability to report overstay rates.13 We found that DHS had actions completed and unde

overstay data but continued to face challenges in reporting reliable overstay rates. WDHS assess and document the extent to which the reliability of the data used to deveestimates had improved and any remaining limitations in how the data could be usedin its fiscal year 2015 overstay report, DHS noted which data were used to compile thin the report and identified limitations with other data sources, thus addressing our re

• In February 2017, we found that since our 2013 report, DHS had reported some but n

required by statute on potential overstays in the department’s fiscal year 2015 oversta

overstay report described expected overstay rates by country for certain nonimmigranfor business or pleasure through air and sea ports of entry who were expected to depin fiscal year 2015. However, because of data reliability concerns, the report did not inrequired by law, including overstay rates for nonimmigrants who entered the country tentry or under other nonimmigrant categories, such as foreign students. At the time oofficials told us that the department planned to address these limitations in future ove

12GAO-11-411.13GAO-13-683.14GAO-17-170.
DHS Has Developed a Metric to Calculate the Overs

• DHS has developed a metric to calculate the number and rate of overstays, an

and sea overstay data in an annual overstay report. 

• The metric to calculate the overstay rate is:

Suspected in-country overstays in a fiscal year + out of country overstays in 

Total expected departures in a fiscal year

• As presented in the annual report, the overstay rate is an automated calculatio

number of nonimmigrant admissions to the United States through air or sea ponot depart in a fiscal year divided by the total number of expected departures 

• The overstay rate is based on those nonimmigrants who were expected t

fiscal year regardless of when they were admitted. 

• Also, the rate calculates overstays by entry rather than by individual. For 

nonimmigrant enters multiple times during the year and overstays more tincident when the visitor remains longer than the authorized period of admas a separate overstay.
DHS Has Developed a Metric to Calculate the Overs

(cont.)• The annual overstay report also describes the characteristics of suspected in-

country overstays by

• Certain classes of admission, including: Visa Waiver Program countries (

pleasure nonimmigrants); non-Visa Waiver Program countries (business 

nonimmigrants); student and exchange visitors; and all other in-scope no

• Country of citizenship.

• DHS’s fiscal year 2017 overstay report includes information on expected depa

in-country overstays, out-of-country overstays, total overstays, and the total acountry overstay rates by country of citizenship and for each class of admissioabove.

15Other in-scope nonimmigrant classes of admission include, among others: temporary workers and trainees; intracom

fiancées of U.S. citizens. The 2017 overstay report presents figures pertaining to Canada and Mexico separately from 

because air and sea information represent a smaller portion of the Canadian and Mexican travel population, as the maMexican nonimmigrants enter the United States at land ports. 
DHS Has Implemented a Process to Develop the An

Overstay Report• DHS produces the overstay report through a series of steps, as shown in table 

Table 2: Steps Taken to Produce and Validate Overstay Report

Step Federal Stakeholder Action1 U.S. Customs and Border 

Protection (CBP)

Performs an initial data extraction from ADIS of all nonimmigrants e

fiscal year but no departure or status adjustment was received.

2 U. S. Citizenship and 

Immigration Services

Determines whether a potential overstay has received an extension

their status through an automated analysis of CLAIMS data.

3 CBP Validates overstay data by matching known information about a non

biometrics) to other information, such as their name.

4 Department of Homeland

Security (DHS) Office of Immigration Statistics (OIS)

Receives extract of ADIS data to validate. Conducts an independen

additional quality assurance checks to identify and evaluate potenti

5 CBP and OIS Perform a final validation.6 DHS Executives review overstay data and report.7 CBP Publishes the overstay report to Congress and the public.

Source: GAO analysis of DHS documents. | GAO-19-298R
DHS Has Taken Steps to Improve Its Overstay Metr

2014• In late 2014, at CBP’s request, IAO conducted an assessment of the fiscal yea

report development process. The assessment found that CBP’s methodology also identified potential issues and gaps, including data reliability concerns, anissue the fiscal year 2014 overstay report. 

• Further, IAO did not assess the data inputs and systems quality and accuracy 

year 2014 overstay report. As a result, the assessment noted that IAO could na level of confidence in the overstay data contained within the report. IAO reconext step that IAO conduct an in-depth review of entry and exit data systems (IDENT, and CLAIMS) to assess the completeness of CBP data. Although CBP that IAO complete the assessment, CBP officials stated that they have and co

with other stakeholders, including ICE and USCIS, to improve the quality of thoverstay data from the supporting data systems and in ADIS. 
DHS Has Taken Steps to Improve Its Overstay Metr

2014 (cont.)• CBP, ICE, and USCIS took corrective actions to address the findings and reco

the assessment that allowed DHS to report overstay data beginning with the freport. These actions included developing:

• Standard operating procedures to ensure the same methodology is used 

following years for reporting overstays (fiscal year 2015).

• A revision to ADIS that facilitates the exchange of immigration status cha

in real-time (fiscal year 2015).

• A dedicated ADIS reporting tool that automated the process of generating 

according to CBP officials, reduces errors and improves the efficiency of year 2017). We observed a CBP official recreate the fiscal year 2017 oveADIS reporting tool. We observed that the tool is user-friendly and quickly 

• A new CBP process with ICE to better facilitate sharing data for certain ty

visas. This effort resulted in capturing an “end date” by which foreign studthe country or otherwise be considered overstays. As a result, DHS was student data in the fiscal year 2016 report for the first time. ICE and CBP other with daily updates of SEVIS and ADIS data (fiscal year 2016). 

• Based on these and other improvements, CBP has included more complete d

overstays report on more classes of admission over time, such as including fobeginning in fiscal year 2016. Further, CBP officials stated that they have a higconfidence in the overstay metric and reliability of the data presented in the fisoverstay report. 
DHS Has Taken Steps to Improve Its Overstay Metr

2014 (cont.)• To improve the reliability of data used to identify overstays and to complement 

collection that exists, CBP has made progress developing and implementing a capability to track air passenger exits using facial recognition technology.16

• According to a September 2018 DHS OIG report, CBP’s Biometric Entry-Exit P

a pilot at nine airports and demonstrated ability using this technology to match passengers’ identities at departure gates to biometrics collected during previoCBP and other government entities. The OIG reported that CBP expects to buby supporting airline use of the biometric capability for a greater volume of flig

16Since 1996, a series of federal statutes has required that the federal government develop and implement, and report t

implementation of, an entry and exit data system to match records, including biographic and biometric identifiers, of fore

leaving the country, and to identify overstays. See, e.g., Illegal Immigration Reform and Immigrant Responsibility Act of 

div. C, tit. I, subtit. A, § 110, 110 Stat. 3009-546, 3009-558 to -559 (classified, as amended, at 8 U.S.C. § 1365a); IntelligPrevention Act of 2004, Pub. L. No. 108-458, tit. VII, subtit. B, § 7208, 118 Stat. 3638, 3817-23 (classified, as amended, February 2017, we reported that DHS has made progress in planning for a biometric air exit system and has tested biomchallenges remain. See GAO-17-170.

17OIG-18-80.
DHS’s 2017 Overstay Report Accounts for Almost A

Sea Nonimmigrant Visits with Expected Departures Fiscal Year • DHS’s fiscal year 2017 overstay report states that the report accounts for abo

air and sea nonimmigrants expected to depart in fiscal year 2017. The remainpertained to classes of admission who are unlikely to overstay, according to Ddiplomats and flight crews).

• According to the fiscal year 2017 overstay report, there were about 52.7 millio

admissions to the United States through air or sea ports of entry who were excountry in fiscal year 2017. DHS counted about 702,000 overstays (1.33 perceidentified about 607,000 suspected in-country overstays and 95,000 out-of-co
DHS’s 2017 Overstay Report Accounts for Almost A

Sea Nonimmigrant Visits with Expected Departures Fiscal Year (cont.)• As shown in table 3, the air and sea overstay rate decreased from fiscal year 2

2017, according to the overstay reports.

Table 3: Overstay Rates, as Reported by DHS in its Fiscal Years 2016 and 2017 Overstay 

• The overstay report provides a snapshot of overstays at a particular point in ti

year), but a significant number of overstays depart the United States shortly adeparture date according to the 2017 overstay report.

• As of January 24, 2018, the fiscal year 2017 suspected in-country overst

decreased from 1.15 percent (606,926 overstays) to 0.94 percent (494,7May 1, 2018, this rate had decreased to 0.80 percent (421,325 overstays

• The fiscal year 2017 overstay report includes a new section on examining 

durations, which shows that 92 percent of the 94,974 out-of-country overcountry within the first 50 days after their “admit until” date.

Fiscal year Total overstay rate Suspected in-country 

overstay rate

Out-of-country ove

2016 1.47% 1.25% 0.22%2017 1.33% 1.15% 0.18%

Source: GAO analysis of Department of Homeland Security (DHS) data. | GAO-19-298R
Overstay Reports Do Not Account for the Total Air a

Overstay Population• While the fiscal year 2017 overstay report identified the number of air and sea 

nonimmigrant status was to expire in fiscal year 2017, it did not include a metrthe total air and sea overstay population in the United States at a given time a2018 Explanatory Statement. Specifically, the report did not include air and se

were expected to depart in prior years and who may remain in the United Stat

• According to CBP officials, overstay data prior to fiscal year 2015 are unreliab

officials stated that they have the capability to track prior air and sea suspectefiscal year 2015 and could report these data. We observed that ADIS has the generate reports of the total number of overstays since fiscal year 2015. CBP they are considering including the total number of suspected overstays expectfiscal year 2015 in future reports.
Overstay Reports Contain Limited Information for T

Crossing at Land Ports• Due to existing limitations in collecting departure data in the land environment

report provides limited departure and overstay information for land ports of enprimarily to match records of certain travelers arriving into the United States bthose that may have subsequently departed by land to Canada.

• The collection of departure information in the land environment is more difficul

sea environments due to the major physical, logistical, and operational obstacelectronically collecting an individual’s biographic and biometric data. Additionenvironment, it is not feasible to obtain advance reporting of arrivals and depa

majority of travelers cross the borders using their own vehicle or as a pedestri

• Unlike other countries, a majority of nonimmigrants from Canada and Mexico 

States through land ports. Although the overstay report does not include data enter the United States through land ports, according to the fiscal year 2017 ois able to reconcile a significant portion of nonimmigrants who enter through pborders with Canada and Mexico, since the majority of those nonimmigrants acrossers and CBP is able to close a previous arrival when recording a new arr
Overstay Reports Contain Limited Information for T

Crossing at Land Ports (cont.)• On the northern border, under the 2011 U.S.-Canada Beyond the Border decla

States and Canada exchange biographic entry records for land crossings betwcountries, so that an entry into one is recorded as an exit from the other. Howecurrently only includes third-country nationals (i.e., non-Canadian citizens), buunder consideration in the Canadian Parliament that would allow the sharing odata. According to the 2017 overstay report, CBP matches 98.6 percent of the received from Canada to an entry in ADIS. CBP uses this information to match 

air and sea arrivals into the United States for those cases where the traveler minto Canada.

• According to DHS, the southwest border with Mexico does not present the sam

the border with Canada because Mexico’s border infrastructure is more limitedMexico does not collect data on all nonimmigrants who enter the country. 
DHS Is Piloting Initiatives to Better Identify Oversta

Nonimmigrants Who Travel Through Land Ports• DHS has efforts underway to collect biographic and biometric data on traveler

• In fiscal year 2017, CBP began planning for a pilot test at the San Luis an

Arizona, ports of entry to demonstrate the feasibility of acquiring photos odeparting travelers and comparing those photos using facial recognition tgovernment databases. CBP officials stated that the pilot test for arriving the San Luis Port of Entry in September 2018 and the Nogales Port of En2018.

• Beginning in December 2017, CBP and its Mexican counterpart agency b

data on travelers departing the United States at the San Ysidro, Californiausing radio frequency identification, which is included on many forms of dtypically carried by Mexican nationals, according to CBP officials.

(103062) 
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