United States General Accounting Office

GAO Report to the Committee on the

Judiciary, U.S. Senate and the

Committee on the Judiciary, House of

Representatives

December 1997 ILLEGAL

IMMIGRATION

Southwest Border

Strategy Results

Inconclusive; More

Evaluation Needed

GAO/GGD-98-21

GAO United States

General Accounting Office

Washington, D.C. 20548

General Government Division

B-276689 

December 11, 1997

The Honorable Orrin G. Hatch, Chairman

The Honorable Patrick J. Leahy

Ranking Minority Member

Committee on the Judiciary

United States Senate

The Honorable Henry J. Hyde, Chairman

The Honorable John Conyers, Jr.

Ranking Minority Member

Committee on the Judiciary

House of Representatives

Illegal immigration has been a long-standing problem. The U.S.

Department of Justice, Immigration and Naturalization Service (INS)

estimated there were about 5 million illegal aliens residing in the United

States in October 1996, and their numbers increased at an average rate of

about 275,000 per year between October 1992 and October 1996. Congress

and states with large illegal immigrant populations have raised concerns

about illegal immigrants’ fiscal impact on government programs,

participation in criminal activities, and overall effect on local economies.

In February 1994, the Attorney General announced a broad, five-part

strategy to strengthen enforcement of the nation’s immigration laws (see

app. I). The strategy’s first priority was to deter illegal entry by

strengthening border enforcement, particularly along the southwest

border of the United States. Since February 1994, the Justice Department

and INS—the primary Justice Department agency charged with enforcing

the nation’s immigration laws—have issued various documents and

produced strategies intended to reinforce and better define the Attorney

General’s overall strategy to deter illegal entry. Within INS, the Border

Patrol is responsible for preventing illegal entry along the border between

the nation’s ports of entry, and the Inspections program is responsible for

preventing illegal entry at the ports of entry. For ease of presentation, and

unless otherwise noted, we use the term “strategy” in this report to refer to

various documents, including policy directives and strategies, that have

been issued by the Attorney General, INS’ Border Patrol, and INS’

Inspections program as well as others.

The Illegal Immigration Reform and Immigrant Responsibility Act of 1996

(1996 Act) mandates us to track, monitor, and evaluate the Attorney

General’s strategy to deter illegal entry into the United States and to report

Page 1 GAO/GGD-98-21 Illegal Immigation
B-276689 

annually for 6 years.1 As agreed with your committees, this report focuses

on the strategy to deter illegal entry along the southwest border.

Specifically, the report addresses (1) what the strategy calls for;

(2) actions taken to implement the strategy along the southwest border;

(3) whether available data confirm the strategy’s hypotheses, with respect

to expected initial results from the strategy’s implementation along the

southwest border; and (4) the types of indicators that would be needed to

evaluate the Attorney General’s strategy to deter illegal entry along the

southwest border. Our future reports will address various other aspects of

the Attorney General’s five-part strategy to deter illegal entry.

Results in Brief To carry out the priority to strengthen the detection of and deterrence to

illegal entry along the border, the Attorney General’s strategy called for the

Border Patrol to (1) allocate additional Border Patrol resources in a

four-phased approach starting first with the areas of highest known illegal

activity; (2) make maximum use of physical barriers; (3) increase the

proportion of time Border Patrol agents spend on border enforcement

activities; and (4) identify the appropriate mix of technology, equipment,

and personnel needed for the Border Patrol. At ports of entry along the

southwest border, the strategy called for the Inspections program to

increase inspector staff and use additional technology to increase the

deterrence to and detection of illegal entry and improve management of

legal traffic and commerce. The strategy also called for implementing

sanctions against aliens who attempt fraudulent entry, and using

technology.

Since the strategy was issued in 1994, INS has made progress in

implementing some, but not all, aspects of the strategy. As of

September 1997, the Border Patrol had nearly completed Phase I of its

strategy, which was to focus resources in the areas of highest known

illegal activity (the San Diego and El Paso sectors) and was moving into

phase II, which is to focus resources in the next highest known areas (the

Tucson sector and in south Texas). Thus, the Border Patrol has allocated

additional agents in general accordance with the strategy. As called for in

the strategy, INS had added barriers along the southwest border, although

more barriers are reportedly still needed. The strategy also called for

increasing border enforcement activity, as measured by the proportion of

time Border Patrol agents collectively spent on border enforcement. The

total number of hours spent on border enforcement activities in the

southwest border sectors has been increasing since 1994 because the

1

P.L. 104-208, sec. 107.

Page 2 GAO/GGD-98-21 Illegal Immigation
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number of Border Patrol agents increased. However, the proportion of

time Border Patrol agents at the southwest border collectively spent on

border enforcement activities did not increase between 1994 and the first

half of 1997; rather the proportion remained the same at about 59 percent.

The Border Patrol has not identified the most appropriate mix of staffing

and other resources needed for its Border Patrol sectors as called for in

the strategy. The Border Patrol is developing a computerized staffing

model to help it identify the right mix of staffing and technology.

At the southwest border land ports of entry, INS has added about 800

inspector positions since fiscal year 1994, thereby increasing its on-board

strength to about 1,300, as of March 1997. To help achieve its goal of

increasing deterrence to illegal entry, INS has also instituted various

enforcement initiatives including increased prosecutions of aliens

presenting false documents and has been pilot testing various technologies

to improve operations. INS has also been planning for the implementation

of various border control requirements that Congress mandated in the

1996 Act.2

INS and other data indicate that some of the initial results of the strategy’s

implementation along the southwest border correspond with the expected

results stated in the strategy. However, sufficient data were not available

for us to determine whether other expected results have occurred.

According to the strategy, the concentration of resources in phases would

make it more difficult and costly for illegal aliens to cross the border, and

many would ultimately be deterred from entering altogether. The strategy

expected (1) an eventual reduction in illegal alien apprehensions in areas

where control is gained; (2) a shift in the flow of illegal alien traffic from

sectors that traditionally accounted for most illegal immigration activity to

other sectors; (3) increased attempts to enter illegally through the ports of

entry; (4) increases in the costs of illegal alien smuggling, and the use of

more sophisticated tactics to smuggle illegal aliens into the country; (5) a

decrease in attempted reentries by those who have previously been

apprehended; and (6) reduced violence at the border.

INS data indicated that, as a percentage of total apprehensions along the

southwest border, apprehensions of illegal aliens have decreased in the

two sectors that in 1993 accounted for the most apprehensions and

received the first influx of new resources—San Diego and El Paso. In

addition, INS’ apprehension data and other anecdotal data are consistent

2

Provisions in Subtitle A, Title I of the 1996 Act require INS to take several actions to improve

enforcement at the border. Appendix II discusses the status of the actions not discussed elsewhere in

the report.

Page 3 GAO/GGD-98-21 Illegal Immigation
B-276689 

with a shift in attempted illegal entries from the San Diego and El Paso

sectors to other sectors and from the traditional entry corridors within the

San Diego, El Paso, and Tucson sectors to other locations within those

sectors. As the Border Patrol added resources between the ports of entry,

some ports along the southwest border experienced increases in aliens

using fraudulent documents and making false claims to United States

citizenship to attempt to enter the United States, but other ports did not,

according to INS data and INS officials. INS intelligence reports and other

data suggest that the fees charged by smugglers and the sophistication of

smuggling methods have increased since the implementation of the

strategy, all indicating, according to INS, an increased difficulty in illegally

crossing the border. However, these data do not indicate whether the

increased difficulty of entry has deterred the flow of illegal entries into the

country, the ultimate goal of the Attorney General’s strategy. Data were

not available for us to determine whether there had been a decrease in

attempted reentries by those who had previously been apprehended. On

the basis of available data, we could not determine the extent to which the

strategy had reduced border violence.

The Attorney General’s strategy for deterring illegal entry across the

southwest border envisions three distinct but related results: fewer aliens

will be able to cross the border illegally; fewer aliens will try to illegally

immigrate into the United States; and, consequently, the number of illegal

aliens in the United States will decrease. The information that INS has

reported on apprehensions, attempted fraudulent entries at ports of entry

and other interim effects, and INS intelligence reports on changes in illegal

alien traffic provide only a partial picture of the effects of increased

border control. Evaluating the overall effectiveness of the strategy for

deterring illegal entry poses complex questions that would require a

formal, rigorous plan for (1) collecting and analyzing consistent and

reliable data on several different indicators related to the three expected

results from the strategy and (2) examining their interrelationships. In

addition to the data INS has reported, we identified a variety of other

indicators that may be useful in providing information on some aspects of

each of the results envisioned by the strategy to illustrate the concept of

how a more comprehensive assessment of the border strategy as a whole

could be devised.

At present, although the Justice Department believes that systematic

evaluation of major programs and initiatives is important, it has no formal

evaluation plan to systematically evaluate the effectiveness of the Attorney

General’s strategy. INS officials told us that they are developing a list of

Page 4 GAO/GGD-98-21 Illegal Immigation
B-276689 

indicators that they believe may help INS undertake such an evaluation.

However, key aspects of a formal evaluation plan, such as what data will

be collected, by whom, and how the overall effectiveness of the strategy

will be evaluated have yet to be determined.

Although developing a formal evaluation plan and implementing a rigorous

and comprehensive evaluation of the strategy may prove to be both

difficult and potentially costly, without such an evaluation the Attorney

General and Congress will have no way of knowing whether the billions of

dollars invested in reducing illegal immigration have produced the

intended results. Developing a formal evaluation plan would be in keeping

with the concepts embodied in the Government Performance and Results

Act of 1993 (the Results Act) to develop evaluations and performance

measures to gauge whether the goals and objectives are being achieved.

Although, in response to the Results Act, the Justice Department’s draft

strategic plan described some specific program goals, strategies, and

performance indicators, it did not contain an evaluation component to

explain how the Department will assess success in meeting these goals or,

more broadly, the effectiveness of the southwest border strategy. A formal

evaluation plan would assist Justice in identifying whether INS is

implementing the strategy as planned, what aspects of the strategy are

most effective, and, if the strategy’s goals are not being achieved, the

reasons they are not. Such information would help the agency and

Congress identify whether changes are needed in the strategy, in policy, in

resource levels, or in program management.

Background INS’ overall budget has more than doubled within 5 years, from $1.5 billion

in fiscal year 1993 to $3.1 billion in fiscal year 1997. INS has spent about

$2.3 billion on border enforcement from fiscal years 1994 through 1997.

For fiscal year 1997, the combined budget for INS’ Border Patrol and

Inspections programs—the two programs responsible for deterring illegal

entry along the border—was nearly $800 million. INS, through other INS

programs, provides additional support for the strategy by allocating funds

for computer automation, technology procurement, and construction of

barriers.

INS’ Border Patrol is responsible for preventing and detecting illegal entry

along the border between the nation’s ports of entry. The Border Patrol

has 21 sectors, 9 of which are along the southwest border.

Page 5 GAO/GGD-98-21 Illegal Immigation
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Figure 1: INS Regions and Border Patrol Sector Headquarters Along the Southwest Border

Western Region Eastern Region Central Region

San Diego

El Centro

Yuma

Tucson

El Paso

Marfa

Del Rio

Laredo

McAllen

Source: INS.

Page 6 GAO/GGD-98-21 Illegal Immigation
B-276689 

The Border Patrol’s appropriations were $631 million for fiscal year 1997,

a 69 percent increase over its $374 million expenditure for fiscal year 1994.

As of July 21, 1997, the Border Patrol had about 6,500 agents nationwide.

About 6,000, or 92 percent, were located in the nine sectors along the

southwest border. In fiscal year 1996, the Border Patrol apprehended

about 1.6 million aliens nationwide, of whom 1.5 million were

apprehended in sectors along the southwest border. (Appendix III

contains detailed staffing and selected workload data for the Border

Patrol.)

INS Inspections and the U.S. Customs Service3 share responsibility for

inspecting all applicants for admission at the U.S. ports of entry. The

purpose of their inspections is to prevent the entry of inadmissible

applicants by detecting fraudulent documents, including those

representing false claims to U.S. citizenship or permanent residence

status, and seize conveyances used for illegal entry. Figure 2 depicts INS’ 36

land ports of entry along the southwest border.

3

Customs and INS inspectors perform inspections at the primary inspection booths at land ports of

entry. INS and Customs inspectors are cross-trained and cross-designated to carry out both agencies’

inspection responsibilities at U.S. ports of entry.

Page 7 GAO/GGD-98-21 Illegal Immigation
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Figure 2: INS Land Ports of Entry Along the Southwest Border

San Ysidro, CA (2)

Tecate, CA

Calexico, CA

San Luis, AZ

Andrade, CA

Lukeville, AZ

Sasabe, AZ

Nogales, AZ (2)

Naco, AZ

Douglas, AZ

El Paso, TX (2)

Fabens, TX

Presidio, TX

Del Rio, TX (2)

Eagle Pass, TX

Laredo, TX (3)

Rio Grande City, TX

Hildalgo, TX

Brownsville, TX (2)

Santa Teresa,TX

Fort Hancock, TX

Ysleta, TX

Falcon Heights, TX

Los Ebanos, TX

Los Indios, TX

Progreso, TX

Roma, TX

Columbus, NM

Pharr, TX

Note: Some locations have more than one port of entry.

Source: INS.

Page 8 GAO/GGD-98-21 Illegal Immigation
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As of March 30, 1997, INS Inspections had about 1,300 inspectors at ports of

entry along the southwest border. The Inspections’ appropriation was

$151 million for fiscal year 1997, a 78 percent increase from its $85 million

expenditure for fiscal year 1994. As of March 15, 1997, the U.S. Customs

Service had about 7,400 inspectors nationwide. Of these 7,400 inspectors,

2,200, or 30 percent, were located along the southwest border to inspect

individuals and cargo. In fiscal year 1996, INS and Customs inspectors

along the southwest border inspected about 280 million people, including

84 million, or 30 percent, who were U.S. citizens. (App. III contains

detailed staffing and selected workload data for INS Inspections.)

Within the Department of Justice, the 94 offices of the U.S. Attorneys are

responsible for prosecuting individuals charged with committing offenses

under U.S. law, including persons who illegally enter the United States.

Because the Justice Department determined that it does not have the

resources necessary to prosecute all illegal entrants, the U.S. Attorneys

located in districts along the southwest border have instituted a policy to

focus criminal prosecutions on alien smugglers, and on those aliens

without legal documentation who are linked directly to violence and crime

in the community. The policy calls for imposing administrative, rather than

criminal, sanctions on first-time violators who do not otherwise have

criminal histories. In October 1995, the Attorney General appointed the

U.S. Attorney for the Southern District of California as her Special

Representative for Southwest Border Issues. This collateral responsibility

includes coordinating the border law enforcement activities of various

Justice Department agencies, including INS, the Drug Enforcement

Administration, and the Federal Bureau of Investigation, with the activities

undertaken by the Departments of the Treasury and Defense.

The Department of State also has a role in deterring illegal entry along the

southwest border. Mexican nationals who seek to visit the United States

can obtain a border-crossing card, a type of entry document, from either

State Department consulates in Mexico or from INS at ports of entry.

According to the State Department, insufficient staffing levels overseas,

ineffective interagency cooperation over the exchange of data, and needed

computer enhancements all contribute to a weakening of management

controls in the visa issuance function.

Scope and

Methodology

To determine what the Attorney General’s strategy to deter illegal entry

called for, we reviewed and summarized information on border control

strategies, plans, and directives contained in a variety of Justice

Department and INS documents related to border control and, because the

Page 9 GAO/GGD-98-21 Illegal Immigation
B-276689 

Attorney General had not published a specific strategy for the southwest

border, we prepared a summary of these documents (see app. I). Not all of

the documents used were specifically identified as “strategy” documents.

Justice Department officials reviewed this summary in May 1997 and

agreed that it accurately reflected the Attorney General’s strategy and its

various components at that time.

To determine what actions had been taken to implement the strategy along

the southwest border and whether initial results expected from the

strategy’s implementation have occurred, we conducted in-person

interviews with officials from six of the nine Border Patrol sectors along

the southwest border and telephone interviews with officials from the

remaining three sectors.4

 We interviewed INS officials from the five INS

district offices responsible for all of the ports of entry along the southwest

border, INS Inspections officials from seven ports of entry, and Customs

officials from five ports of entry.5

 In addition, we analyzed INS’ Border

Patrol and Inspections workload and apprehension data, reviewed

documents pertaining to INS’ management priorities, and reviewed INS

intelligence reports and previous reports done by us and the Department

of Justice’s Inspector General. We did not verify the validity of INS

computer generated data related to workload and apprehension statistics.

However, we discussed with INS officials their data validation efforts.

These officials were confident that the data could be used to accurately

portray trends over time. We met with the U.S. Attorney for the Southern

District of California, who is also the Attorney General’s Southwest Border

Representative, to discuss aspects of the strategy related to prosecuting

those that violate immigration laws. We also discussed with INS and State

Department officials the status of various border control efforts to deter

illegal entry mandated by the 1996 Act. In conjunction with one of these

efforts—improvements in border-crossing identification cards—we visited

State Department consulates in Ciudad Juarez and Tijuana, Mexico.

To identify indicators that could be used to evaluate the effectiveness of

the strategy in deterring illegal entry, we reviewed illegal immigration

research studies and interviewed officials from INS and the U.S.

4

We visited the Border Patrol sectors in San Diego and El Centro, California; Tucson, Arizona; and El

Paso, Laredo, and McAllen, Texas, and held telephone discussions with officials from the Yuma,

Arizona, and Del Rio and Marfa, Texas, sectors.

5

We visited the ports of entry in San Ysidro, Otay Mesa (INS only), and Calexico (INS only) California;

Nogales Arizona; and El Paso, Laredo, and Brownsville, Texas. These ports were chosen because they

were in locations identified in the strategy as high priority areas.

Page 10 GAO/GGD-98-21 Illegal Immigation
B-276689 

Commission on Immigration Reform.6 We also convened a meeting with a

panel of immigration researchers7

 to obtain their views on a range of

evaluation issues, such as appropriate indicators of the strategy’s

outcome, sources of relevant data in addition to INS, the reliability of

existing data, and how data should be analyzed.

We did our work between December 1996 and September 1997 in

accordance with generally accepted government auditing standards. We

requested comments on a draft of this report from the Attorney General,

the INS Commissioner, the Acting Customs Commissioner, and the

Secretary of State or their designees. On September 16, 1997, the INS

Executive Associate Commissioner for Policy and Planning provided us

with oral comments, which are discussed near the end of this letter. The

Customs Service had no comments on our report and the Department of

State provided technical corrections only.

The Strategy In February 1994, the Attorney General announced a five-part strategy to

strengthen enforcement of the nation’s immigration laws. The strategy

included

• strengthening the border,

• removing criminal aliens,

• reforming the asylum process,

• enforcing workplace immigration laws, and

• promoting citizenship for qualified immigrants.

The strategy to strengthen the border called for “prevention through

deterrence,” that is, to raise the risk of being apprehended for illegal aliens

to a point where they would consider it futile to try to enter the United

States illegally. The strategy was to involve concentrating new resources

on the front lines at the most active points of illegal activity along the

southwest border.

To carry out the priority to strengthen the border, the Border Patrol was

to, among other things, (1) concentrate personnel and technology

resources in a four-phased approach, starting first with the sectors with

the highest level of illegal immigration activity (as measured by

apprehensions) and moving to the areas with the least activity; (2) make

maximum use of physical barriers to deter entry along the border;

6

Section 141 of the Immigration Act of 1990 (P.L. 101-649) established the Commission to examine and

make recommendations regarding the implementation and impact of U.S. immigration policy.

7

The names and affiliations of the panel participants are listed in appendix IV.

Page 11 GAO/GGD-98-21 Illegal Immigation
B-276689 

(3) increase the proportion of time Border Patrol agents spent on border

control activities; and (4) identify the appropriate quantity and mix of

technology and personnel needed to control the border.

Recognizing that increased enforcement by the Border Patrol might force

some aliens to try to enter the United States illegally through the ports of

entry, the strategy calls for INS’ Inspections program to increase the

number of inspectors and the use of technology to both deter and detect

illegal entry and improve management of legal traffic and commerce. For

example, to deter illegal entry the strategy called for increasing the

number of illegal aliens referred for prosecution and testing automated

fingerprint technology to detect inadmissible aliens. To improve

management of legal traffic, the strategy called for providing the public

with more information so they would be better prepared for the inspection

process.

In concert with INS’ efforts to deter illegal entry, the strategy calls for

increasing felony prosecutions of alien smugglers and those criminal

aliens who have repeatedly reentered the United States after having been

removed.

In addition, the 1996 Act requires the Attorney General to take additional

border control measures to deter illegal entry into the United States.

Appendix II discusses the status of these efforts not discussed elsewhere

in this report.

Implementation of the

Strategy

INS has made progress in implementing the Attorney General’s strategy to

deter illegal entry along the southwest border. In September 1997, Border

Patrol officials told us that the Border Patrol had nearly completed phase I

of the strategy, which called for allocating Border Patrol resources to the

San Diego, California, and El Paso, Texas, sectors. They stated that the

Border Patrol was now moving into phase II of the strategy, which called

for increasing resources in the Tucson, Arizona, sector and three sectors

in south Texas—Del Rio, Laredo, and McAllen. INS officials told us they

could not speculate as to when they would complete the remaining

aspects of the strategy, that called for focusing resources in the remaining

three sectors along the southwest border (phase III) and the sectors along

the rest of the U.S. land border and coastal waterways (phase IV).

Page 12 GAO/GGD-98-21 Illegal Immigation
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As part of phase I of the strategy, in October 1994, INS launched a major

initiative in San Diego called Operation Gatekeeper.8

 This multiphase,

multiyear operation was designed to reduce illegal immigration into San

Diego and to force alien traffic eastward to deter and delay illegal aliens’

attempts to reach urban areas. Resources added to the area as a result of

Gatekeeper included new Border Patrol agents and support staff, new

inspectors at the San Ysidro port of entry, new computers and technology

to maximize efficiency, and new resources for the Office of the U.S.

Attorney for the Southern District of California to increase its capability to

prosecute criminal aliens. Gatekeeper focused first on the area of the

greatest illegal immigration activity—the 5-mile stretch of Imperial Beach,

California. The next phase, which began in June 1995, included intensified

enforcement at the San Ysidro port of entry and the rural parts of the San

Diego sector. In December 1994, we reported that on the basis of initial

positive results, the strategy appeared encouraging.9

In August 1997, INS began the next major phase of its strategy by

concentrating resources in the McAllen sector, starting first in

Brownsville, Texas. Named Operation Rio Grande, INS plans to add agents

and equipment, such as high-powered vision scopes and stadium type

lighting, to the McAllen sector to deter illegal entry.

The Border Patrol has generally allocated its additional resources in

accordance with the strategy and has made progress in constructing

barriers along the southwest border. However, the agents’ percentage of

time spent on border enforcement has not increased in most southwest

border sectors since 1994, and the Border Patrol has yet to determine the

best mix of agents and technology on which to base future staffing

allocations. INS’ Inspections program has deployed additional inspectors to

the southwest border and is in the process of pilot testing various

technology initiatives designed to deter illegal entry and streamline the

inspections process. In addition, the U.S. Attorneys in the five districts

along the southwest border increased the number of prosecutions for

certain immigration violations.

8

In September 1993, prior to the strategy being announced, INS began Operation Hold-the-Line, in El

Paso, Texas. In addition, in October 1994, INS began Operation Safeguard in Arizona to respond to the

increase in apprehensions there.

9

Border Control: Revised Strategy Is Showing Some Positive Results, (GAO/GGD-95-30, Dec. 29, 1994).

Page 13 GAO/GGD-98-21 Illegal Immigation
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Border Patrol Has

Generally Allocated New

Agents and Other

Resources in Accordance

With Strategy

With some exceptions, the Border Patrol was generally able to allocate its

additional resources according to the strategy, allocating first to sectors

with the highest level of known illegal immigration activity. In fiscal year

1993, the San Diego and El Paso sectors had the highest levels of

apprehensions of illegal immigrants, accounting for 68 percent of all

apprehensions along the southwest border. In fiscal year 1994, INS received

funding for an additional 350 agents and assigned these new agents to San

Diego and El Paso, the sectors with the highest priority. Three hundred

agents were allocated to the San Diego sector and 50 to the El Paso sector.

The strategy noted that the Border Patrol needed to be flexible to respond

to changing patterns in illegal alien traffic. According to INS officials, the

Border Patrol began to notice “almost immediately” an increase in

apprehensions in other sectors, particularly Tucson and those in south

Texas (Del Rio, McAllen, and Laredo). INS officials attributed this increase

in apprehensions in other sectors to a “shift” in the flow of illegal alien

traffic as it became more difficult to cross illegally in San Diego and El

Paso. Consequently, in fiscal year 1995, the Border Patrol deployed some

of the additional agents funded that year and originally planned for San

Diego and El Paso to the Tucson and south Texas sectors, the sectors with

the next highest priority after San Diego and El Paso.

According to Border Patrol officials, deploying additional agents in a

phased manner was a new approach. Prior to the strategy, as additional

positions became available, the Border Patrol tried to allocate at least a

few additional positions to as many of the 21 sectors as possible. However,

under the strategy, 98 percent (or 2,792) of the 2,850 new Border Patrol

agent positions nationwide authorized from fiscal year 1994 through fiscal

year 1997 have gone to 6 of the 21 Border Patrol sectors.10 INS allocated

1,235 (about 43 percent) of these positions to the San Diego sector and 351

(about 12 percent) to the El Paso sector, sectors with the highest priority.

Nearly all of the remaining 1,264 went to the Tucson and the south Texas

sectors, the sectors with the next highest priority (see fig. 3).

10Of 2,850 new positions, 2,842 were authorized for the southwest border and 8 for Puerto Rico.

Page 14 GAO/GGD-98-21 Illegal Immigation
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Figure 3: Allocation of New Agent

Positions by Southwest Border Patrol

Sector, Fiscal Years 1994 Through

1997

0

200

400

600

800

1,000

1,200

1,400

1,235

50

0

602

351

0

152 124

328

Number of new positions

San Diego El Centro Yuma Tuscon El Paso Marfa Del Rio Laredo McAllen

Phase I Phase II Phase III Phase I Phase III Phase II

Note: Total number of new agent positions authorized for the southwest border for fiscal years

1994 through 1997 equals 2,842.

Source: INS.

As shown in figure 4, the additional allocations have resulted in an

increase in on-board staff in most southwest border sectors. Overall, the

number of Border Patrol agents on board along the southwest border

increased 76 percent between October 1993 and July 1997.

Page 15 GAO/GGD-98-21 Illegal Immigation
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Figure 4: Number of On-Board Agents by Southwest Border Patrol Sector, October 1993 Compared With July 1997

San Diego El Centro Yuma Tucson El Paso Marfa Del Rio Laredo McAllen

0

500

1,000

1,500

2,000

2,500

980

194 178

281

602

131

290 347 386

2,188

204 168

817

901

132

414 444

689

October 1993

July 1997

Number of on-board agents

Note: Total on-board agents on the southwest border as of October 1993 equals 3,389. Total

on-board agents on the southwest border as of July 1997 equals 5,957.

Source: INS.

To complement the increase in staffing, southwest border sectors have

also received additional technology, equipment, and infrastructure

improvements in accordance with the Border Patrol strategy. For

example, between October 1994 and October 1996, the San Diego sector

added almost 5 miles of permanent high-intensity lighting, 8 miles of

reinforced steel fencing, 28 infrared scopes (a night-vision device), and 3

helicopters to detect illegal entry. El Paso sector officials told us they

received six additional infrared scopes and expected to receive five more

Page 16 GAO/GGD-98-21 Illegal Immigation
B-276689 

soon, and in March 1997, the sector completed a 3.5 mile fencing project.

INS purchased a building for a new Border Patrol station in Nogales,

Arizona, to house the increased number of new agents.

In March 1997, the Border Patrol submitted a 5-year staffing plan to

Congress covering fiscal years 1996 through 2000. The plan calls for

adding between 1,500 and 2,500 additional Border Patrol agents in fiscal

years 1998 through 2000. This is fewer than the 3,000 additional agents

whom the 1996 Act authorized INS to hire over the 3-year period because,

according to INS officials, they were concerned that their staff was growing

faster than they could properly manage and that they did not have an

adequate infrastructure (facilities, equipment, training, and supervisory

capacity) to absorb 3,000 new agents. INS plans to assign two-thirds of the

new agents to Arizona and Texas; the remainder will go to states along the

northern border and Gulf Coast.

Progress in Installing

Barriers Between Ports of

Entry

One of the main efforts outlined in the strategy is the “maximum utilization

of lighting, fencing, and other barriers” by all sectors, although the strategy

did not outline specific barrier projects or miles of fencing to be built. A

1993 border control study, commissioned by the U.S. Office of National

Drug Control Policy (Sandia Study), recommended fencing and in some

cases vehicle barriers in every southwest border patrol sector to deter

illegal entry.11 While INS has not formally endorsed all of the Sandia Study

recommendations, INS Headquarters Border Patrol officials told us that

some recommendations, such as erecting 90 miles of barriers along the

southwest border, are valid. These officials told us that, while adding

barriers is part of the strategy, INS has left it up to each sector chief to

propose where and when to build barriers. Seven of the nine sector plans

written to carry out the strategy cite the need for barriers to increase

agents’ effectiveness in apprehending illegal aliens and reducing crime.

According to INS officials, proposals for barrier projects are reviewed in

the context of INS’ budget process; require consultation with Congress; and

must be coordinated with the U.S. Department of Defense Joint Task

Force Six, the military unit that constructs much of the fencing for INS.

Congress has also emphasized the need for additional fencing. The 1996

Act requires the Attorney General, in consultation with the Commissioner

of INS, to take such actions as may be necessary to install additional

physical barriers and roads in the vicinity of the U.S. border to deter illegal

11Systematic Analysis of the Southwest Border, Sandia National Laboratories, Albuquerque, New

Mexico, January 1993.

Page 17 GAO/GGD-98-21 Illegal Immigation
B-276689 

crossings in areas of high illegal entry into the United States. In carrying

out this provision in the San Diego sector, the 1996 Act requires the

Attorney General to provide for second and third fences, in addition to the

existing reinforced fence, and for roads between the fences for the 14

miles of the international land border of the United States extending

eastward from the Pacific Ocean.12

INS has allocated $8.6 million of its fiscal year 1996 and 1997

appropriations to complete the first two phases of the triple fencing

project in the San Diego sector. Of the $8.6 million allocated, about

$4.3 million had been obligated for expenditure as of July 1997. According

to a San Diego sector official, INS is in the process of acquiring the

property upon which to build the fencing and conducting environmental

assessment reports, before construction can begin in certain areas. Figure

5 depicts bollard-type (concrete cylindrical columns set in a staggered

manner) fencing13 which is being constructed in the area immediately

inland from the Pacific Ocean in the San Diego sector.

12Sec. 102(a) and (b).

13According to INS officials, the fencing is divided into (1) 1.8 miles of bollard fencing; (2) 1.5 miles of

steel mesh fencing, about 15 feet in height; and (3) other type of fencing still in the design phase to

cover the remainder of the 14 miles.

Page 18 GAO/GGD-98-21 Illegal Immigation
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Figure 5: Bollard Fencing Being Constructed in San Diego, California

Insert: Bollard fencing showing electronic 

security access gate. Gate is to have mesh-like

covering over the openings.

Source: INS.

Prior to 1994, very little substantial fencing existed—about 14 miles of

reinforced steel fencing in the San Diego sector. Since the strategy was

Page 19 GAO/GGD-98-21 Illegal Immigation
B-276689 

announced, INS has built approximately 32 miles of new fencing in five

sectors. As of July 1997, nearly 24 miles of additional fencing was under

construction. Most of the fencing constructed, under construction, or

planned to be built is in the San Diego sector. Currently, no barriers exist

or are planned to be built in four Texas sectors (Marfa, Del Rio, Laredo,

and McAllen). However, two of these sectors (Laredo and McAllen) had

indicated a need for barriers in their sector plans. INS officials cited the

need to overcome community concerns as a reason why they have not

built more barriers.

Table 1: Status of Barriers Along the

Southwest Border Border Patrol

sector

Miles built

before 1994

Miles built

since 1994

Miles under

construction Miles planned

San Diego 14.0 18.7 5.5a 2.0

El Centro 0 3.0 0 3.0

Yuma 0 4.5 0 3.0

Tucson 0 2.0b 3.5 2.0

El Paso 0 3.5 14.0 0

All other sectorsc 0 0 0 0

Total 14.0 31.7 23.0 10.0

aAs mandated in the 1996 Act, 14 miles of secondary fencing to supplement the primary border

fence is also being built.

bDoes not include 2 miles of fencing in Naco, Arizona, since INS did not fund the construction.

cIncludes Marfa, Del Rio, Laredo, and McAllen, Texas sectors.

Source: GAO analysis of INS data.

The majority of the fencing construction along the southwest border has

been accomplished by the U.S. Department of Defense Joint Task Force

Six and, to a lesser degree, the National Guard. The military provides the

personnel to construct the fencing and pays for their salaries,

transportation, meals, and housing. INS typically pays for building materials

(although steel runway landing mats are provided at no cost because they

are military surplus) and other costs, such as equipment rental. INS

employees, such as repair and maintenance staff, also help with the

construction. In a few instances, private contractors have been hired by

INS to construct particular types of fencing, such as the bollard fencing

project in the San Diego sector. However, INS officials stated that the use

of private contractors is much more costly to INS than using military

assistance.

Page 20 GAO/GGD-98-21 Illegal Immigation
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Proportion of Time Spent

on Border Enforcement

Did Not Increase in Most

Southwest Border Sectors

The strategy called for an increasing border enforcement activity, as

measured by the proportion of time Border Patrol agents spent on border

enforcement. According to INS data, agents in the nine sectors along the

southwest border collectively spent 59 percent of their total time on

border enforcement in the first half of fiscal year 1997, nearly reaching the

servicewide goal of 60 percent. However, this proportion of time spent on

border enforcement activities was the same as that in fiscal year 1994.

Although the proportion of time spent on border enforcement activities

did not increase during this period, the total number of hours spent by all

Border Patrol agents on border enforcement activities along the southwest

border has been increasing since fiscal year 1994, because the overall

number of Border Patrol agents assigned to the southwest border sectors

increased.

In five of the nine southwest border sectors, the proportion of time that

Border Patrol agents spent on border enforcement in the first half of fiscal

year 1997 was within 2 percentage points (plus or minus) of what it was in

fiscal year 1994. In two sectors, Tucson and El Paso, the proportion of

time spent on border enforcement decreased by 7 and 13 percentage

points, respectively. In two other sectors, San Diego and Marfa, it

increased by 7 and 10 percentage points, respectively (see fig. 6).

Page 21 GAO/GGD-98-21 Illegal Immigation
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Figure 6: Percentage of Agents’ Time Spent on Border Enforcement by Southwest Border Sector, Fiscal Year 1994

Compared With First Half of Fiscal Year 1997

San Diego El Centro Yuma Tucson El Paso Marfa Del Rio Laredo McAllen

0

20

40

60

80

100

50

60

66

56

77

56

61

75

54

57 58

68

49

64 66

61

74

55

Percentage of border enforcement time spent

Fiscal year 1994

First half of fiscal year 1997

Increase Increase Increase Increase

Source: GAO analysis of INS data.

INS officials reported that an increase in the amount of time spent on

program support activities such as supervision, training, and processing

apprehended aliens, as well as possible reporting errors, could have

hindered increasing the overall percentage of time spent on border control

activities. For example, during fiscal year 1994, the El Paso sector spent

20 percent of its time on program support compared with 33 percent

during the first half of fiscal year 1997, an increase of 13 percentage points.

During this same time period, the Tucson sector’s percentage of time on

program support increased from 41 percent to 50 percent, an increase of

9 percentage points.

Page 22 GAO/GGD-98-21 Illegal Immigation
B-276689 

Consistent with the strategy, southwest border sectors have redirected

Border Patrol agents from general enforcement14 activities back to border

control. For example, the San Diego sector reduced the proportion of time

spent on general enforcement from 4 percent in fiscal year 1994 to less

than 1 percent for the first half of fiscal year 1997. The Marfa sector

reduced the proportion of time spent on general enforcement from

14 percent to 2 percent during this same time period. As a result, Marfa

increased its border enforcement percentage although it did not receive

additional staff during this period.

Servicewide, the proportion of time spent on border enforcement declined

from 56 percent in fiscal year 1994 to 50 percent in the first half of fiscal

year 1997. Thus, the performance of INS as a whole on this measure

declined rather than increased as intended. INS has lowered its

expectations regarding the percentage of time, servicewide, that it expects

its Border Patrol agents to spend on border enforcement. According to its

fiscal year 1998 budget submission, INS’ 1998 servicewide goal is for the

Border Patrol to spend 56 percent of its time on border enforcement

compared with the 60 percent goal for fiscal year 1997.

Appropriate Mix of Agents’

Staffing and Materiel

Resources Had Not Been

Determined

The strategy states that it will “seek the best mix of technology and

personnel resources to meet the long term goals,” and that “improvements

in technology will make border control strategies more effective and less

resource intensive.” The Border Patrol has been increasing its supply of

equipment and advanced technologies. The conference report for the

fiscal year 1997 Department of Justice Appropriations Act includes

$27 million for infrared scopes, low-light television systems, sensors,15 and

the replacement of three helicopters, including upgraded forward-looking

infrared systems.16 Since 1994, the San Diego sector alone acquired an

additional 28 infrared scopes, about 600 underground sensors, about 500

vehicles, about 600 computers, and several advanced computer systems.

The Border Patrol has not identified the most appropriate mix of staffing

and other resources needed for its sectors. Headquarters officials told us

that sector chiefs may have taken current technological assets into

14General enforcement activities include checking employers for illegal workers and visiting local jails

and state prisons to locate and process criminal aliens.

15Sensors include devices buried in the ground used to detect either foot or vehicular traffic that may

have crossed the border illegally.

16Departments of Commerce, Justice, and State, the Judiciary, and Related Agencies Appropriations

Act, P.L. 104-208; H.R. Conf. Rep. 104-863, at 788 (1996).

Page 23 GAO/GGD-98-21 Illegal Immigation
B-276689 

consideration when developing their sector staffing proposals. However,

according to these officials, sector staffing proposals generally did not

include a discussion of the potential impact on staffing needs of adding

barriers and/or technology. In addition, when allocating the additional

1,000 Border Patrol agents funded for fiscal year 1997 to the various

sectors, the Border Patrol did not formally consider how adding barriers

and/or technology would potentially affect staffing needs.

In the 5-Year Border Patrol Deployment Plan submitted to Congress in

March 1997, the Border Patrol stated that in fiscal year 1998, it would

“assess technology improvements in sensors, scopes, biometrics

identification systems, etc., and effects on staffing requirements”; and in

fiscal year 1999, it would “implement staffing changes based on technology

assessments.” With the help of a contractor, the Border Patrol is currently

working on developing a computerized staffing model to help it identify

the right mix of staffing and technology. According to Border Patrol

officials, the model will allow INS to estimate the impact of different levels

of materiel resources on sectors’ staffing levels and effectiveness in

apprehending illegal aliens. As of June 1997, the model was being tested in

the El Paso sector. INS officials plan to have this model operational in El

Paso by December 1997 and in all southwest border sectors by the

summer of 1998.

INS headquarters officials told us that they were also testing new

technologies, such as weight-sensitive sensors and satellite global

positioning systems, to determine their usefulness in Border Patrol

operations. They told us that they have yet to determine how these new

technologies might be integrated into border control operations and what

their impact on agent needs might be.

Resources, Enforcement

Initiatives, and Technology

Testing Increased at Ports

of Entry

The strategy postulated that enhanced enforcement efforts between the

ports of entry would cause an increase in port-of-entry activity, including

increased attempts to enter through fraudulent means.17 To handle the

increased activity, Congress authorized an increase of about 800

inspectors for southwest ports of entry since 1994 (see fig. 7), almost

doubling the number of authorized positions, from about 865 in 1994 to

1,665 in 1997. As of March 1997, 1,275 inspectors were on board at land

ports of entry along the southwest border (see fig. 8).

17Fraudulent entries could include persons presenting counterfeit documents or altered immigration

documents; persons making a documented false claim of U.S. citizenship, such as presenting a

counterfeit U.S. birth certificate; persons making oral false claims to U.S. citizenship; or persons being

smuggled through the port of entry concealed in vehicles.

Page 24 GAO/GGD-98-21 Illegal Immigation
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Figure 7: Allocation of New Inspectors

to Land Ports of Entry Along the

Southwest Border by INS District

Office, Fiscal Years 1994 Through 1997

0

100

200

300

400

364

122 119

76

115

Number of new positions

San Diego

District

Phoenix

District

El Paso

District

San Antonio

District

Harlingen

District

Note: Total number of new inspector positions authorized for fiscal years 1994 to 1997 equals

796. Ports of entry fall under the administration of district offices.

Source: INS.

Page 25 GAO/GGD-98-21 Illegal Immigation
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Figure 8: Number of On-Board

Inspectors at Land Ports of Entry

Along the Southwest Border by INS

District Office, September 1994

Compared With March 1997

0

100

200

300

400

500

600

230

88

139

120 126

490

191

236

168

190

San Diego 

District

Number of on-board inspectors

Phoenix

District

El Paso

District

San Antonio

District

Harlingen

District

September 1994

March 1997

Note: Total number of on-board inspectors on the southwest border as of September 1994 equals

703. Total number of on-board inspectors on the southwest border as of March 1997 equals

1,275. Ports of entry fall under the administration of district offices.

Source: INS.

INS has begun testing a number of programs and systems to increase

deterrence to illegal entry and improve and streamline the inspection

process. These efforts are intended to prevent illegal aliens and criminal

violators from entering the United States and facilitate the entry of legal

travelers. To accomplish these objectives, INS is using technology to

segment people seeking admission by risk category and forming strategic

partnerships with others concerned with border management, such as the

Page 26 GAO/GGD-98-21 Illegal Immigation
B-276689 

Customs Service, local communities, and the Mexican government. INS is

also planning to measure its effectiveness in detecting illegal entry

attempts.

According to port-of-entry officials, the additional INS inspectors have

enabled INS to staff more inspection booths at peak hours, and allowed

both INS and Customs to increase enforcement efforts and undertake some

new initiatives to deter illegal entry. For example, inspectors at some ports

of entry are spending more time inspecting vehicles before they reach the

inspection booth to detect concealed drugs or smuggled aliens.

INS believes that increased sanctions will result in deterring illegal aliens

from attempting to enter the United States fraudulently. In response to an

increase in attempted fraudulent entries at ports of entry in the San Diego

area, the Justice Department established the first permanent immigration

court facility to be located at a port of entry. The “port court,” located at

the Otay Mesa port of entry, began as a pilot project in July 1995 and was

made permanent in October 1995. This program was intended to eliminate

costly and time-consuming transportation of aliens to the immigration

court in downtown San Diego and allowed for the immediate

implementation of the immigration judge’s order of exclusion and

deportation.

In addition, INS inspectors in San Diego worked with the U.S. Attorney for

the Southern District of California to develop a program intended to

increase prosecutions of persons attempting to enter the United States

fraudulently. However, the ability to prosecute may be hampered by the

limited availability of detention space, according to Inspections officials.

Provisions in the 1996 Act that took effect April 1, 1997, provide for the

expedited removal of certain aliens who attempt fraudulent entry. INS

officials believe these provisions may also help deter attempted fraudulent

entry.

INS has several pilot projects under way that use technology to try to

segregate low- and high-risk traffic and streamline the inspections process.

In the San Diego area, a dedicated commuter lane is in operation. INS

authorizes certain frequent crossers and their vehicles to enter the United

States through a preclearance process. Through an automated photo

identification and card system, registered vehicles and occupants can pass

through the port of entry quickly.18 INS is testing other technology,

18INS performs random inspections of vehicles in the dedicated commuter lane, and the use of the lane

is not for commercial entry of goods.

Page 27 GAO/GGD-98-21 Illegal Immigation
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including automated vehicle license-plate readers to check vehicles

against law enforcement lookout databases and a system which uses palm

prints and fingerprints to verify the identity of individuals in order to

reduce passenger processing time.

In addition, according to INS headquarters and most port officials we

interviewed, INS and Customs have increased cooperation between their

agencies and are working together to manage the ports in a more efficient

manner. In 1993, we reported on the lack of cooperation and coordination

of border crossing operations as well as a long history of interagency

rivalries between INS and Customs.19 We recommended that the Director of

the Office of Management and Budget (OMB), working with the Secretary of

the Treasury and the Attorney General, develop and present to Congress a

proposal for ending the dual management of border inspections. As a

result of our report, INS and Customs formed Port Quality Improvement

Committees (PQIC) at selected ports of entry, including some along the

southwest border. A 1996 follow-up report on the Vice President’s National

Performance Review indicated that the PQIC structure encouraged and

strengthened cooperation and communication among officers of all

federal inspection service personnel.20 In addition, Customs and INS

reviews have found that better coordination and improved services have

been achieved through PQICs. Four of the ports we visited (San Ysidro, El

Paso, Nogales, and Brownsville) had PQICs and had implemented various

cooperative initiatives to facilitate border crossing (e.g., increased

cross-training). We did not independently assess whether the PQICs have

resulted in better coordination and cooperation between INS and Customs

because such an assessment was beyond the scope of this review.

As part of its efforts to measure performance, as required by the Results

Act, INS plans full implementation in fiscal year 1998 of a port performance

measurement system, which is to include randomly selecting applicants

who seek to cross into the United States and processing them through a

more rigorous inspection. One of the goals of this system is to project the

estimated number of immigration related violations. According to INS

headquarters officials, this system will ensure the effectiveness of

inspections at the officer level and will allow for evaluation of overall

program performance.

19Customs Service and INS: Dual Management Structure for Border Inspections Should Be Ended,

(GAO/GGD-93-111, June 30, 1993).

20Reengineering United States Primary Passenger Processing, First Year Summary Report, National

Performance Review, 1996.

Page 28 GAO/GGD-98-21 Illegal Immigation
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Prosecutions The strategy called for increasing prosecutions for immigration related

violations. As part of the strategy, U.S. Attorneys in the five judicial

districts contiguous to the southwest border have developed federal

prosecution policies to, among other things, target criminal aliens,

smugglers, and those who attempt entry by using false documents. The

strategy also outlines the expanded use of administrative sanctions

through immigration court orders.

U.S. Attorneys in the five districts along the southwest border have

increased the number of prosecutions since 1994. For example, in fiscal

year 1994, the 5 districts filed about 1,000 cases involving about 1,100

defendants related to 3 major immigration violations.21 The Justice

Department projected that these 5 districts would file about 3,800 such

cases in fiscal year 1997, involving over 4,000 defendants, more than

tripling the number of cases and defendants.22 The U.S. Attorney for the

Southern District of California, which includes San Diego, projected that

his office would file about 1,900 such cases in fiscal year 1997, over 6 times

the 290 filed in 1994.

Some Anticipated

Interim Effects of

Strategy Are

Occurring

As the strategy along the southwest border is carried out, the Attorney

General anticipated the following changes in certain indicators would

provide evidence of the interim effectiveness of the strategy:

(1) an initial increase in the number of illegal aliens apprehended in

locations receiving an infusion of Border Patrol resources, followed by a

decrease in apprehensions when a “decisive level of resources” has been

achieved, indicating that illegal aliens are being deterred from entering;

(2) a shift in the flow of illegal alien traffic from sectors that traditionally

accounted for most illegal immigration activity to other sectors as well as

shifts within sectors from urban areas where the enforcement posture was

greater to rural areas;

(3) increased attempts by illegal aliens to enter illegally at the ports of

entry, as it becomes more difficult to enter between the ports;

21These are 8 U.S.C. 1324, which provides criminal penalties for bringing in or harboring aliens; 8

U.S.C. 1325, which provides criminal penalties for improper entry by aliens; and 8 U.S.C. 1326, which

provides criminal penalties for reentry of an alien after deportation.

22Fiscal year 1997 numbers are a straight-line projection based on actual data through the end of

March 1997. Fiscal year 1997 actual statistics were not available at the end of our field work.

Page 29 GAO/GGD-98-21 Illegal Immigation
B-276689 

(4) an increase in fees charged by alien smugglers to assist illegal aliens in

crossing the border and more sophisticated smuggling tactics;

(5) an eventual decrease in attempted reentries by those who have

previously been apprehended (recidivism); and

(6) reduced violence at the border.

According to the strategy, changes in the predicted direction on these

indicators would be evidence that INS enforcement efforts effectively

raised the cost and difficulty of entering the United States illegally.

Ultimately, the strategy posits that there would be fewer illegal aliens in

the United States and reduced use of social services and benefits by illegal

aliens.

Data on the interim effects of the strategy have been collected and

reported primarily by INS, and their interpretation is not clear-cut. The

available data suggest that some of the predicted changes have occurred.

For example, INS data indicate that

(1) there was a period after additional resources were applied to the San

Diego sector in which Border Patrol apprehensions increased in the sector

and a subsequent period in which apprehensions decreased;

(2) there has been a shift in illegal alien traffic from sectors that

traditionally accounted for most illegal immigration activity to other

sectors as well as shifts within some sectors;

(3) there were increased numbers of illegal aliens attempting to enter

illegally at some ports of entry; and

(4) alien smuggling fees may have increased, and smuggling tactics may

have become more sophisticated.

Data were unavailable on whether there has been a decrease in attempted

reentries by those who have previously been apprehended, and data on

violence at the border were inconclusive.

Changes in Illegal Alien

Apprehensions

Apprehension statistics are routinely reported by INS, and they are INS’

primary quantitative indicator of the results of the strategy. Although an

effective strategy should affect apprehensions, apprehension data,

Page 30 GAO/GGD-98-21 Illegal Immigation
B-276689 

standing alone, have limited value for determining how many aliens have

crossed the border illegally. (A later section discusses the limitations of

apprehension data more fully.)

According to INS data for the San Diego sector, after an increase in

apprehensions, as resources were applied, sector apprehensions

eventually began to decrease. According to an INS analysis of seasonally

adjusted San Diego sector apprehension data from October 1992 to March

1997 (see fig. 9), monthly sector apprehensions were on a downward trend

from February 1993 through December 1994. In January 1995, 3 months

after the sector began applying Operation Gatekeeper resources in the

western part of the San Diego sector, apprehensions began increasing.

Apprehensions continued to increase for about 1 year. Beginning in

January 1996, apprehensions started to decline and continued to do so

through March 1997 (the end point of the INS analysis). The last decline in

apprehensions coincided with the addition of Border Patrol agents,

barriers, and technology to areas of the San Diego sector that were east of

the original Gatekeeper effort.

Page 31 GAO/GGD-98-21 Illegal Immigation
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Figure 9: Apprehensions (Seasonally

Adjusted) in the San Diego Border

Patrol Sector, October 1992 to

March 1997

Oct 92 Oct 93 Oct 94 Oct 95 Oct 96

0

10,000

20,000

30,000

40,000

50,000

60,000

Total apprehensions (seasonally adjusted)

Operation gatekeeper (began October 1994)

Peso devaluation (December 1994)

Spring initiative (began January 1996)

Years

Source: INS.

It is difficult to determine whether the increase in apprehensions

experienced in 1995 is due to increased enforcement or other factors. In

December 1994, the Mexican government devalued the peso. According to

INS officials and INS reports, apprehensions in the San Diego sector could

have increased in part due to the strategy and in part due to an increase in

illegal flow resulting from poor economic conditions in Mexico and the

associated devaluation of the peso. It is also difficult to determine whether

the decline in apprehensions that began in January 1996 was part of the

Page 32 GAO/GGD-98-21 Illegal Immigation
B-276689 

original downward trend predicted by the strategy or a specific result of

the spring initiative—INS’ 1996 enhancement to Operation Gatekeeper—in

which additional resources were applied to the eastern parts of the San

Diego sector.23

In El Paso, the pattern of apprehensions following implementation of a

separate border enforcement initiative, Operation Hold the Line, differed

from that of San Diego. In this operation, begun in September 1993, the

sector redeployed its agents directly to a 20-mile section of the border in

the metropolitan El Paso area adjoining Ciudad Juarez in Mexico and

maintained a high-profile presence that was intended to deter illegal aliens

from attempting to cross the border. According to an INS analysis of

seasonally adjusted apprehension data, apprehensions decreased in the El

Paso sector immediately after the initiative was launched, and after

declining for a period of 1 month, apprehensions began to increase (see

fig. 10). Although the Border Patrol has continued Operation Hold-the-Line

and added new agents to the sector between fiscal years 1994 and 1997,

apprehension levels began to increase in November 1993, and have

generally continued to do so through March 1997, although remaining at

levels below those that existed before September 1993.

23In July 1996, the Department of Justice Office of the Inspector General (OIG) began a broad

investigation into allegations by members of the Border Patrol union that Operation Gatekeeper was

characterized by the manipulation of procedures and data to create the false impression that the

initiative had successfully deterred illegal immigration into the San Diego sector. The OIG

investigation has been completed, although a report on the results has not yet been issued. In

August 1997, OIG officials told us that their report on Gatekeeper, which they expect to issue in

November 1997, will not affirm that pervasive falsification of Gatekeeper data occurred.

Page 33 GAO/GGD-98-21 Illegal Immigation
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Figure 10: Apprehensions (Seasonally

Adjusted) in the El Paso Border Patrol

Sector, October 1992 to March 1997

Oct 92 Oct 93 Oct 94 Oct 95 Oct 96

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

Hold-the-line (began September 1993)

Peso devaluation (December 1994)

Years

Total apprehensions (seasonally adjusted)

Source: INS.

Shift in Illegal Alien Traffic The Border Patrol strategy directed additional enforcement resources first

to the San Diego and El Paso sectors, where the majority of illegal entries

have historically occurred. INS expected that the flow of illegal alien traffic

would shift from San Diego and El Paso to other sectors as control was

achieved. Our analysis of INS apprehension data indicate that a shift in

apprehensions has occurred. As shown in figure 11, in the first 6 months of

fiscal year 1993 the San Diego and El Paso sectors accounted for

68 percent of all southwest border apprehensions. However, during the

first 6 months of fiscal year 1997, San Diego and El Paso accounted for

33 percent of all southwest border apprehensions. Other sectors now

account for a larger share of the apprehensions. For example, in the first 6

months of fiscal year 1993, the Tucson sector accounted for 7 percent of

all southwest border apprehensions. During the first half of fiscal year

Page 34 GAO/GGD-98-21 Illegal Immigation
B-276689 

1997, the sector’s share rose to 19 percent. The proportion of southwest

border apprehensions of the three south Texas sectors—McAllen, Laredo,

and Del Rio—rose from 19 percent to 37 percent over the same period.

Figure 11: Apprehensions in San Diego, El Paso, and Other Southwest Border Patrol Sectors, First Half of Fiscal Years

1993 and 1997

First half of FY 1993 First half of FY 1997

San Diego

23%

32%

Other

sectors

45%

El Paso

San Diego

23.6%

67%

Other

sectors

9.5%

San Diego

24%

9%

El Paso

a a

aIncludes El Centro, Yuma, Tucson, Marfa, Del Rio, Laredo, and McAllen.

Source: GAO analysis of INS data.

The Border Patrol’s enforcement posture aimed to reduce illegal entries

into large urban areas, thereby, forcing illegal alien traffic to use rural

routes where the Border Patrol believes it has a tactical advantage. Our

analysis of INS apprehension data shows that within the San Diego, El

Paso, and Tucson sectors, apprehensions have decreased in areas that

have received greater concentrations of enforcement resources and

increased in more remote areas. As shown in figure 12, in the San Diego

sector, the stations of Imperial Beach and Chula Vista, which provide the

shortest established routes to urban San Diego, accounted for 61 percent

Page 35 GAO/GGD-98-21 Illegal Immigation
B-276689 

of the sector apprehensions in the first half of fiscal year 1993.24 In the first

half of fiscal year 1997, these two stations accounted for 39 percent of the

sector’s apprehensions. Conversely, in the other stations, largely in rural

sections of the sector, the share of total apprehensions increased from

39 percent to 61 percent over the same time period.

Figure 12 : Apprehensions by Border Patrol Stations in the San Diego Sector, First Half of Fiscal Years 1993 and 1997

Chula Vista station

Imperial Beach station

Other stations

33% 28%

39%

11%

28%

61%

Chula Vista station

Imperial Beach station

Other stations

First half of FY 1993 First half of FY 1997 

Source: GAO analysis of INS data.

In the El Paso sector, the proportion of apprehensions in the urban El

Paso station dropped from 79 percent of all sector apprehensions in the

first 6 months of fiscal year 1993, to 30 percent in the first 6 months of

fiscal year 1997, as shown in figure 13. A 1994 study commissioned by the

U.S. Commission on Immigration Reform concluded that Operation

Hold-the-Line appeared to have substantially deterred some types of illegal

24The nine Border Patrol sectors along the southwest border are each divided into a number of

stations, with responsibility for a section of the border or a geographic area further in the interior of

the United States. Most sectors also maintain several checkpoints along major highways, designed to

intercept aliens who have eluded agents along the border.

Page 36 GAO/GGD-98-21 Illegal Immigation
B-276689 

crossers but not others.25 Using official statistics on apprehensions and

crossings at the ports of entry (e.g., police and crime data, birth and

hospital data, education and school attendance statistics, sales tax and

general sales data) and qualitative information from in-depth interviews

with government officials and persons at border crossing sites in El Paso

and Ciudad Juarez, the study concluded that the operation had been more

successful in curtailing illegal immigration among aliens who crossed

illegally from Ciudad Juarez to engage in illegal work or criminal activity

in El Paso (local crossers) than among aliens who crossed at El Paso but

were headed for other U.S. destinations (long-distance labor migrants).

According to the study, a substantial amount of long-distance labor

migration appeared to have been diverted to other locations along the

southwest border. Border Patrol officials in the El Paso sector told us in

March 1997 that the majority of illegal aliens entering the sector were

long-distance migrants, so they believed that their enforcement efforts

were continuing to deter local crossers.

25F.D. Bean, R. Chanove, R.G. Cushing, R. de la Garza, G.P. Freeman, C.W. Haynes, & D. Spener, Illegal

Mexican Migration & the United States/Mexico Border: The Effects of Operation Hold-the-Line on El

Paso/Juarez (Austin, TX: Population Research Center, University of Texas at Austin, and U.S.

Commission on Immigration Reform), July 1994.

Page 37 GAO/GGD-98-21 Illegal Immigation
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Figure 13: Apprehensions by Border Patrol Station in the El Paso Sector, First Half of Fiscal Years 1993 and 1997

First half of FY 1993 First half of FY 1997 

El Paso station

All other

stations

El Paso station

All other

stations

79%

21% 70%

30%

Source: GAO analysis of INS data.

Apprehension data also provide some support that a shift occurred in

illegal alien traffic from the urban area of Nogales, Arizona, targeted by the

Border Patrol in the first phase of its enforcement strategy in the Tucson

sector, to other stations in the sector. As shown in figure 14, in the first 6

months of fiscal year 1993, the Nogales station accounted for 39 percent of

all sector apprehensions. In the first 6 months of fiscal year 1997, the

station accounted for 28 percent of all sector apprehensions. Over this

same period, apprehensions have increased in the city of Douglas, Arizona,

from 27 percent to 43 percent of all sector apprehensions.

Page 38 GAO/GGD-98-21 Illegal Immigation
B-276689 

Figure 14: Apprehensions by Border Patrol Station in the Tucson Sector, First Half of Fiscal Years 1993 and 1997

Nogales station

Other stations

Douglas station

Nogales station

Other stations

Douglas station

39%

27%

34%

28%

43% 29%

First half of FY 1993 First half of FY 1997

Source: GAO analysis of INS data.

Other information also indicates that there has been a shift in alien traffic.

According to an INS report on Operation Gatekeeper, data from INS’

automated fingerprinting system, known as IDENT, showed that illegal

aliens were less likely to try to cross in Imperial Beach in January 1995

than in October 1994. According to an April 1996 report summarizing the

results from an INS Intelligence conference held in the Del Rio sector,

potential illegal aliens had been channeled away from the U.S. urban areas

on the southwest border to more inhospitable areas. The report stated that

a sizeable number of apprehensions were being made in extremely

desolate areas of the border, and this was taken to be an indication that

illegal aliens were trying to avoid Border Patrol deployments. However,

according to the report, INS lacked the resources to apprehend aliens

traversing the remote areas. The report suggested that the Border Patrol

should not abandon its high-visibility deterrent posture in the urban areas

Page 39 GAO/GGD-98-21 Illegal Immigation
B-276689 

to respond to the remote areas because it would encourage a return to the

earlier entry patterns.

According to some INS sector officials, shifts in illegal alien traffic have had

a negative effect in their sectors. For example, according to a January 1997

Laredo sector report, continued media coverage of Operations

Hold-the-Line and Gatekeeper have discouraged entries in those areas and

made Laredo vulnerable to would-be crossers. Border Patrol officials in

the Del Rio sector told us in May 1997 that because of substantial

increases in illegal alien entry attempts and limited resources, the sector

had limited success in controlling the two main corridors within the

sector. According to INS headquarters officials, such shifts in illegal traffic

are not failures of the strategy; rather, they are interim effects.

The strategy has also produced some effects that INS did not anticipate. INS

officials told us that they were in some cases caught unaware by some of

the changes in illegal alien traffic and the tactics of illegal crossers. For

example, INS Western Region officials told us that the increases in illegal

alien traffic that they predicted would occur in the Tucson, Arizona, and

McAllen, Texas, sectors happened earlier than they expected. According

to these officials and San Diego sector officials, the mountains in the

eastern section of the San Diego sector were expected to serve as a

natural barrier to entry. They were surprised when illegal aliens attempted

to cross in this difficult terrain as it became more difficult to cross in the

urban sections of the sector.

Changes in Illegal Entry

Attempts at Ports of Entry

The strategy anticipated increases in the flow of illegal traffic through the

ports of entry as it became more difficult to cross between the ports.

According to INS regional and district officials, some of these anticipated

increases had begun to occur. Officials from the San Diego district told us

that they had seen large increases in attempts to enter the United States

using fraudulent documents or making false claims to U.S. citizenship

immediately following the increase of resources to the Border Patrol in the

San Diego sector. According to San Diego district inspections data, the

number of fraudulent documents intercepted increased about 11 percent

from fiscal year 1994 to 1995 (from about 42,000 to about 46,500), and the

number of false claims to U.S. citizenship increased 26 percent (from

about 15,400 to about 19,400). Officials in El Paso told us they uncovered

more fraudulent documents after the initiation of Operation Hold-the-Line.

El Paso district inspections data show a steady increase in the number of

fraudulent documents intercepted from fiscal year 1994 (about

Page 40 GAO/GGD-98-21 Illegal Immigation
B-276689 

8,200) through fiscal year 1996 (about 11,000). The Del Rio intelligence

conference report stated that Border Patrol enforcement efforts had

forced more people to attempt entry fraudulently through the ports of

entry. Officials from the Phoenix district, however, told us that they had

not seen any significant change in the number of fraudulent documents

intercepted at Arizona ports of entry, as the Border Patrol resources

increased in the Tucson, Arizona sector.

INS Western Region and San Diego District officials told us that they had

not expected the volume of people trying to enter illegally at the ports of

entry in the San Diego areas to be as large as it was after Operation

Gatekeeper or the tactics illegal aliens chose to try to get past the

inspectors. For example, at various times during 1995, illegal aliens

gathered at the entrance to the San Ysidro port of entry and attempted to

overwhelm inspectors by running in large groups through the port. INS

created emergency response teams at the port to deal with these

unexpected tactics and added bollards and other physical barriers to make

unimpeded passage more difficult. In addition, INS asked Mexican

government officials to help prevent large gatherings on the Mexican side

of the border. During our visit to San Ysidro in March 1997, INS officials

told us that due to these actions, large groups of port-runners were no

longer a problem.

It is difficult to determine whether the increases in number of fraudulent

documents intercepted and false claims to U.S. citizenship were a result of

actual increases in illegal entry attempts at the ports or greater efforts

made to detect fraud. The 1994 U.S. Commission on Immigration Reform

evaluation of Operation Hold-the-Line noted that INS inspectors at the

ports of entry in El Paso began checking documents more closely after the

Border Patrol instituted the operation, which may have contributed to the

increase in recorded illegal entry attempts.26

INS headquarters officials disagreed with these findings. They stated that

they believed that inspectors in El Paso were exposed to heavier traffic

flows after the operation began and, therefore, inspectors could have

compensated for the increased workload by doing more cursory reviews

of documents. These headquarters officials stated that increases in

detected fraud reflected actual increases in fraudulent entry attempts,

which were a response to heightened enforcement between the ports of

entry caused by the Border Patrol’s implementation of Operation

Hold-the-Line.

26Bean et al, p. 116.

Page 41 GAO/GGD-98-21 Illegal Immigation
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Alien Smuggling INS expected that if successful, its enforcement efforts along the southwest

border would make it more difficult and costly for illegal aliens and alien

smugglers to cross the border. INS postulated that this should be reflected

in higher fees charged by alien smugglers and more sophisticated tactics

used by smugglers to evade capture by INS.

Fees charged by smugglers, and the sophistication of smuggling methods

have reportedly increased since fiscal year 1994. On the basis of testimony

of the U.S. Attorney for Southern California, INS evaluation reports on

enforcement efforts in San Diego, and INS intelligence reports, fees paid by

illegal aliens to smugglers have increased substantially. Fees for smuggling

illegal aliens across the southwest border have reportedly tripled in some

instances and may be as high as several thousand dollars for

transportation to the interior of the United States.

Intelligence assessments by INS’ Central Region in April and October 1996

concluded that smugglers had become more sophisticated in their

methods of operation. The assessments said that smugglers were more

organized and were transporting aliens further into the interior of the

United States. Similarly, officials from the U.S. Commission on

Immigration Reform told us that their examination of alien smuggling

along the southwest border indicated a trend toward more organized

smuggling.

INS sector officials and documents have reported that changes in alien

smuggling patterns may be having a negative impact in some sectors.

According to a June 1996 Laredo sector intelligence assessment, due to the

success of Operation Gatekeeper and Operation Hold-the-Line, as well as

increased personnel in the McAllen sector, alien smuggling had increased

in the sector. The assessment further stated that limited manpower caused

deterrence to be “negligible” and, consequently, alien smugglers crossed

virtually at any point along the Rio Grande River beyond the area where

the sector focused its enforcement resources. According to the report

from the Del Rio intelligence conference, the increased use of organized

smuggling may make INS’ mission more difficult. For example, most of the

alien smuggling organizations were reportedly “long-haul” groups

transporting aliens to interior work sites via interstate highways. In

addition, according to the report, many of the smuggling organizations that

used to be headquartered in the United States moved their operations out

of the United States, which may make prosecution of the principal leaders

of these organizations more difficult.

Page 42 GAO/GGD-98-21 Illegal Immigation
B-276689 

Recidivism The strategy anticipated eventual reductions in apprehensions of illegal

aliens who had previously been apprehended, as control was gained in

particular locations. According to INS, reductions in recidivism in these

locations would indicate that some illegal aliens are being deterred from

entering. INS has plans to use IDENT, its automated fingerprinting system,

to identify recidivists and analyze their crossing patterns. However, due to

the length of time that it is taking INS to deploy the IDENT system in field

locations, difficulties in getting agents to use IDENT or use it properly, and

computer problems, IDENT to date has provided limited information on

recidivism.

According to INS’ fiscal year 1998 budget request, IDENT systems were to

be installed in 158 fixed locations along the southwest border by the end

of fiscal year 1997. As of October 1, 1997, however, only 140 of these

locations had an IDENT system in place. Of the nine southwest border

sectors, only the San Diego and El Centro sectors had an IDENT system

installed in every fixed location. Even when IDENT has been installed,

according to INS sector officials, it has not always been put in locations

where aliens are apprehended. One of the reasons given for not installing

IDENT in these locations is that it depends on telephone hookup to a

central database, but aliens are not necessarily apprehended where such

telephone communications exist. As a result, many apprehended aliens

have not been entered into IDENT and whether they are recidivists cannot

be readily determined.

Further, according to INS Headquarters officials, even when agents have

access to IDENT, they don’t always use all the system capabilities to

identify recidivists. This reportedly occurs when agents input information

on apprehended aliens into IDENT at the end of their work shift. In such a

case, agents may input apprehended aliens into the system but leave

without determining whether the alien is a recidivist, because doing so

would require additional time for further processing. In addition, if agents

don’t use the IDENT equipment properly (e.g., they do not clean the

platen, which records the fingerprint), they may obtain poor quality

fingerprints from apprehended aliens. This can result in a failure to

identify aliens as recidivists. These situations have been acknowledged as

problems by INS, but the frequency of their occurrence is not known.

Finally, computer problems have affected the usefulness of IDENT data

and INS’ ability to track recidivism over several years. The first year of

IDENT data, which were collected in fiscal year 1995, is not comparable

with data collected in later years because of changes made to the software

Page 43 GAO/GGD-98-21 Illegal Immigation
B-276689 

at the end of 1995. Accordingly, data collected since January 1996 can be

used as a baseline for assessing the effects of the southwest border

strategy, but data collected prior to then cannot be used. In addition,

computer problems arose in fiscal year 1996, affecting the ability of IDENT

to accurately read apprehension dates and times recorded by agents and

to match poor quality fingerprints within the system. INS officials told us

these problems have been corrected and the data have been reprocessed,

validated, verified, and are more consistent. INS officials told us that

although IDENT data gathered since January 1996 are reliable and

accurate, they have not yet been analyzed to examine trends in recidivism.

Changes in Violence at the

Border

The strategy anticipated a reduction in border violence as border control

was achieved. INS officials told us that they anticipated that crime would

decline in those sections of the border where INS invested more

enforcement resources.

The results on this indicator are inconclusive. In November 1996, INS

officials reported that crime statistics for the San Diego area showed that

property crime rates and violent crime rates dropped between 1994 and

1995, after the infusion of resources in the sector. The decreases exceeded

decreases reported for the same time period for the state of California and

the nation as a whole. However, property and violent crime rates were

decreasing in San Diego prior to the infusion of resources. In addition,

according to FBI crime statistics, the crime rate for Imperial Beach, the

area that received the greatest infusion of Border Patrol agents in the San

Diego sector, was 19 percent lower from January to June of 1996

compared with the same period in 1992. However, this decrease was

smaller than the 32 percent decrease for the San Diego region as a whole.

According to an official in the Executive Office for the U.S. Attorneys, the

Executive Office as well as local law enforcement leaders believe that a

more secure border is a material element in the reduction of crime in San

Diego. In addition, according to this official and INS officials, there has

been a significant drop in violence against aliens crossing the border

illegally due to the Mexican government establishing a special group to

patrol its side of the border. According to the Executive Office official,

enhanced coordination between the group and U.S. authorities has had a

profound and positive impact on the level of violence.

The U.S. Commission on Immigration Reform, in its 1994 evaluation of

Operation Hold-the-Line, examined statistics for a number of different

Page 44 GAO/GGD-98-21 Illegal Immigation
B-276689 

types of crimes in El Paso and the age groups involved in committing the

crimes. The evaluation found that certain types of petty crime and

property crime committed by young adults and juveniles had declined in

El Paso after the implementation of the operation. However, the

evaluation report said that the declines were neither statistically

significant nor greater than drops that had occurred in previous years.

Furthermore, linking changes in crime rates to border enforcement efforts

is problematic because there are often no data available on whether

arrested offenders have entered the country illegally. Without this

information, it is difficult to determine what proportion of the reported

declines in crime rates may be due to changes in the number of illegal

aliens arrested for criminal activity.

Formal Evaluation

Based on Multiple

Indicators Would Be

Needed to Assess

Effectiveness of the

Attorney General’s

Strategy

The Attorney General’s strategy for deterring illegal entry across the

southwest border envisions three distinct but related results: fewer aliens

will be able to cross the border illegally; fewer aliens will try to illegally

immigrate into the United States; and, consequently, the number of illegal

aliens in the United States will decrease. However, the indicators presently

used for measuring the overall success of the strategy are not sufficiently

comprehensive to address these three distinct results, and, in many cases,

data are not being gathered systematically. In addition, there is no overall

plan describing how these and other indicators could be used to

systematically evaluate the strategy to deter illegal entry. To gauge the

overall success of the strategy, data would be needed to assess each of the

results envisioned by the strategy and an evaluation plan would be needed

to describe the interrelationship of those results.

To illustrate this point, the strategy could have a desirable effect on the

flow of illegal aliens across the southwest border and, concomitantly, an

undesirable effect on the size of the illegal alien population in the United

States. This could occur if, for example, in response to the strategy, aliens

made fewer illegal trips to the United States, but stayed longer on each

trip, or made a legal trip but overstayed the terms of their visas.

Information would thus be needed on whether a possibly reduced flow

across the border may be an artifact of aliens’ staying in the United States

for longer periods of time than when the border was more porous or

whether aliens were deterred from making attempts at illegal entry at the

border.

Page 45 GAO/GGD-98-21 Illegal Immigation
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Our review of the illegal immigration research literature, interviews with

agency officials, and suggestions on evaluation strategies made to us by

our panel of immigration experts verified the importance of a

comprehensive approach for assessing the effectiveness of the strategy.

Such an approach would require a formal evaluation plan consisting of

indicators that would serve as measures of flow across and to the border

as well as the size of the illegal alien population. We drew on our literature

review and other consultations to identify indicators, some noted by INS

and others not, that might provide useful information. The indicators we

identified are discussed in the following pages and summarized in

appendix V.

It is important to keep several points in mind when contemplating these

indicators:

• First, the indicators we identified address some aspects of each of the

border strategy’s intended results dealing with

• the flow of illegal aliens across the southwest border,

• whether aliens are being deterred from attempting to illegally migrate

into the United States, and

• the number of illegal aliens residing in the United States.

• Second, each indicator or result by itself would be insufficient to assess

the effectiveness of the strategy as a whole, but multiple indicators

drawing on a variety of methods and data sources could contribute to a

more comprehensive evaluation of the effectiveness of the strategy along

the southwest border.

• Third, these indicators should not be viewed as an exhaustive or

all-inclusive list. Our purpose was to illustrate the significance of the

multiple-indicator concept; devising an implementable evaluation strategy

was beyond the scope of this review.

• Fourth, the Government Performance and Results Act (Results Act) of

1993 is intended to improve the efficiency and effectiveness of federal

programs by establishing a system to set goals for program performance

and to measure results. The Results Act requires that agency strategic

plans contain a schedule for future program evaluations. Program

evaluations can be a potentially critical source of information in ensuring

the reasonableness of goals and strategies and explaining program results.

The Results Act defines program evaluations as objective and formal

assessments of the results, impact, or effects of a program or policy.

We recognize that the results envisioned by the strategy are complex and

interrelated and that a rigorous and comprehensive approach to evaluating

Page 46 GAO/GGD-98-21 Illegal Immigation
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the results would be challenging and potentially costly. However, we

believe that the information that would be gained from such an approach

would be important to obtain because it could help identify areas where

Justice might not be achieving the strategy’s objectives and suggest areas

where strategy and policy changes may be necessary. In addition, as

Justice states in its September 1997 Strategic Plan,27 “evaluation identifies

and explains the linkages between the activities and strategies undertaken

and the results achieved . . . [and] enables future planning and resource

decisions to be better informed.”

Indicators of Flow Across

the Border

Historically, inferences about the flow of illegal aliens across the border

have relied heavily on data recorded when aliens are apprehended

attempting to make illegal entry between ports of entry or at ports of

entry. Although the number of apprehensions is a quantifiable measure of

law enforcement activity and INS can collect apprehension information

systematically and completely along the length of the border, it is not a

very good measure of the effectiveness or results of broad strategies, such

as the strategy to deter illegal entry across the southwest border. A major

limitation of apprehension data is that it only provides information on

illegal aliens who have been captured by INS. Because arrested aliens are

the basis for apprehension data, such data provide little information about

illegal aliens who eluded capture, possibly by (1) changing their crossing

patterns and entering in areas where INS has not been able to detect them,

(2) using smugglers to raise the probability of a successful crossing,

(3) entering successfully at the ports of entry with false documents, or

(4) entering legally with a valid visa or border-crossing card and then

overstaying the time limits on these documents or working illegally in the

United States.

INS has, in various contexts, made note of indicators other than

apprehensions to measure the effects of various border-control initiatives.

These indicators include smuggling and crime statistics that were

mentioned in the previous section as indicators of the interim effects of

the strategy. Other indicators on which INS has collected some data in

certain sectors or has reported data collected by others include (1) the

number of migrants staying in hotels and shelters in Mexican border cities,

(2) the number of “gotaways” who are detected by the Border Patrol but

not apprehended, (3) complaints from members of U.S. border

communities about suspected illegal aliens trespassing on their property,

and (4) interview responses by apprehended aliens on the perceived

27The United States Department of Justice Strategic Plan 1997-2002, September 1997.

Page 47 GAO/GGD-98-21 Illegal Immigation
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difficulty of crossing the border. However, INS has collected much of these

data on an ad hoc basis, not systematically and comprehensively in

accordance with a formal evaluation plan. As a result, it is often difficult to

determine the time frame in which the data were collected, the

methodological integrity of the data collection procedures, and the

generalizability of the findings from one area of the border to another.

We reviewed a number of ongoing and completed research projects to

determine what indicators have been identified by others that can be

potentially used in a formal evaluation of the effects of the strategy. These

research projects contain information gathered by immigration

researchers in Mexico and the United States on the crossing patterns and

tactics of Mexicans who have crossed or intend to cross the border

illegally. In addition, the panel of immigration researchers that we

convened for advice on evaluating the effectiveness of the strategy

suggested that information on (1) the social costs and effects of illegal

immigration in border cities; (2) deaths, injuries, and abuses of illegal

aliens; and (3) Mexican efforts to crack down on its border could bolster

an understanding of the strategy’s potential effects on flow across the

border.

Several of the research projects we identified reported information

obtained from interviews with illegal aliens in the United States, potential

illegal aliens in Mexico, Mexicans who had been in the United States

illegally, and illegal and legal immigrants preparing to cross the

U.S.-Mexico border. Although we cannot attest to the quality of data

collected in these research studies, nor that the data were properly

analyzed and interpreted, these research studies have produced

quantitative and qualitative information on the crossing experiences of

illegal aliens—including the number of times individuals have been

apprehended on prior illegal trips, the locations where they have crossed

the border, tactics used to cross the border, whether smugglers were used,

and the overall costs of making an illegal trip. One ongoing project, the

Mexican Migration Project,28 has gathered interview data from migrants

from over 30 communities in Mexico, including detailed histories of border

crossing and migratory experience in the United States covering the past

28This research project is co-directed by Jorge Durand of the University of Guadalajara, Mexico, and

Douglas Massey of the University of Pennsylvania.

Page 48 GAO/GGD-98-21 Illegal Immigation
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30 years. Two other projects conducted by a Mexican university29 gathered

interview data from migrants who were preparing to cross the border

illegally or legally, or who had just returned from the United States to

Mexico. The recently completed Binational Study on Migration gathered

interview data from Mexican migrants and from alien smugglers on such

issues as smuggling costs and tactics and perceptions of United States

border-control efforts.30 (See app. VI for more details on these research

projects, and others listed below, including discussion of their strengths

and weaknesses.)

Members of our expert panel also suggested that evaluations of the

strategy should include indicators of the social costs and benefits of

border enforcement, such as the social and financial effects of illegal

migration on border communities in the United States. As mentioned

earlier, the 1994 U.S. Commission on Immigration Reform evaluation of

Operation Hold-the-Line examined a variety of social indicators in El Paso

to estimate the impact of illegal aliens on these communities and to

determine whether there were any changes in these indicators as a result

of the operation. Future evaluation research could examine these kinds of

indicators in other cities along the southwest border. Such evaluations

would need to take into account differences between border cities in

terms of the enforcement strategies employed by INS, social and cultural

conditions, and the types of illegal aliens that traditionally cross through

these cities.

The panel also recommended more systematic study of deaths, injuries,

and abuse suffered by illegal aliens in crossing the border. Advocacy

groups have raised concerns that the strategy may divert illegal aliens to

more dangerous terrain to cross the border, thereby, producing an

unacceptably high toll in human suffering. A recent study by the University

of Houston’s Center for Immigration Research tracked deaths of illegal

aliens from such causes as automobile-pedestrian accidents, drowning,

and environmental and weather hazards (dehydration, hypothermia,

accidental falls) in counties on the U.S.-Mexico border during the years

29One project, still ongoing, is the Zapata Canyon project, which has surveyed illegal aliens preparing

to cross the southwest border every week since September 1987. The other project, which was

completed, is the Survey of Migration to the Northern Border, which surveyed both illegal and legal

aliens preparing to cross the border or returning from the United States to Mexico between 1993 and

1997. Both projects are directed by Jorge Bustamante of the Colegio de la Frontera Norte in Tijuana,

Mexico, in collaboration with Jorge Santibanez and Rodolfo Corona.

30In March 1994, the governments of the United States and Mexico agreed to undertake a joint study of

migration between the two countries. National coordinators were designated for each country, with

the U.S. Commission on Immigration Reform coordinating the work of U.S. researchers. Results from

the Binational Study on Migration were released in September 1997.

Page 49 GAO/GGD-98-21 Illegal Immigation
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1993 to 1996.31 The study did not find an increase in the overall number of

illegal alien deaths over the time period but did find an increase in the

number of deaths in the remote areas where immigrants have traveled in

an effort to avoid areas of greater enforcement along the border. These

deaths in remote areas were purportedly caused by exposure. The study

also noted that alien deaths were not recorded systematically by any

centralized agency, and local databases were partial and did not use

common standards.

Immigration researchers and INS officials we spoke with agreed that

IDENT data, when more fully available, could be quite useful for

examining the flow of illegal aliens across the border. First, IDENT could

provide an unduplicated count of the number of persons apprehended.

Second, information on the frequency of apprehension of individuals, the

time between multiple apprehensions, and the locations where illegal

aliens are apprehended could provide a greater understanding of how

border enforcement efforts are affecting illegal crossing patterns. Finally,

recidivism data have potential for statistically modeling the flow of illegal

aliens across the border and the probability of apprehension. INS officials

told us in June 1997 that they were examining different analytic techniques

that could be used to model the flow.

Indicators of Deterrence The southwest border strategy is ultimately designed to deter illegal entry

into the United States. It states that “The overarching goal of the strategy

is to make it so difficult and so costly to enter this country illegally that

fewer individuals even try.”32 INS officials told us they had no plans, and

there are no plans in the Attorney General’s strategy, to directly examine

deterrence—that is, the extent to which potential illegal aliens decide not

to make an initial or additional illegal trip to the United States or decide to

limit the number of illegal trips they had planned to take.

According to some research, decisions to migrate illegally are determined

by a complex set of factors; among them are perceptions of border

enforcement efforts; economic conditions in the country of origin; demand

for labor in the United States; and the extent to which social networks are

established that facilitate migration from other countries to the United

31K. Eschbach, J. Hagan, N. Rodriguez, R. Hernandez-Leon, and S. Bailey, Death at the Border

(Houston: Center for Immigration Research, University of Houston), Working Paper #97-2, June 1997.

32Building A Comprehensive Southwest Border Enforcement Strategy (Washington, D.C.: Immigration

and Naturalization Service, June 1996), p. 3.

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States.33 The previously mentioned Mexican Migration Project has

collected some survey information on economic conditions in each of the

communities selected for study as well as the extent of social networks

that facilitate migration from these communities to the United States.

Although the validity of the results would depend greatly on the quality of

the underlying data and the appropriateness of the statistical assumptions

made, data from the project may help to (1) estimate annual changes over

a 30-year period in migrants’ likelihood to take an illegal trip to the United

States and (2) examine the factors contributing to decisions to take an

illegal trip.

The Binational Study also conducted interviews with Mexicans concerning

factors affecting their decisions to migrate illegally. Researchers

interviewed residents of several different types of communities in Mexico

that differed in the extent to which patterns of migration to the United

States had taken hold. In older sending communities, nearly all male

residents had made a trip to the United States, and illegal migration was

seen as a rite of passage. Study directors from the U.S. Commission on

Immigration Reform told us that efforts at deterring illegal migration from

these kinds of communities were unlikely to be effective. However, they

said that deterrence efforts might work better with migrants from newer

sending communities, where social networks were not yet well

established. Some people in these communities reportedly were leaving

because of difficult economic circumstances, while others were staying

because they had heard that the trip was harder, more costly, and more

dangerous. Commission officials told us that an evaluation should include

interviews with residents of older and newer sending communities in

Mexico to ascertain their rationales for undertaking trips to the United

States and their perceptions of border-control efforts.

If the border becomes harder to cross illegally, it is possible that some

migrants who might have crossed illegally may try to enter through legal

means by applying for nonimmigrant visas or border-crossing cards.

Information available from INS and the Department of State on the number

of people applying for nonimmigrant visas and border-crossing cards

could be used to track whether greater numbers of aliens are applying for

legal means of entry. Trends in application rates may be difficult to

interpret in the future, however, since aliens already holding

33See: D. S. Massey & K. E. Espinosa, “What’s Driving Mexico-U.S. Migration? A Theoretical, Empirical,

and Policy Analysis,” American Journal of Sociology, Vol. CII, No. 4 (January 1997), pp. 939-999; and

Binational Study on Migration, Binational Study: Migration Between Mexico & The United States

(Mexico City and Washington, D.C.: Mexican Foreign Ministry and U.S. Commission on Immigration

Reform, September 1997).

Page 51 GAO/GGD-98-21 Illegal Immigation
B-276689 

border-crossing cards will be required to use new cards containing

biometric information, such as the cardholder’s fingerprints, by October 1,

1999.34 Application rates may then overstate the actual demand for legal

entry to the United States.

Indicators of the Number

of Illegal Aliens in the

United States

The strategy anticipates that enforcement activities will ultimately reduce

the number of illegal aliens in the United States and, thereby, reduce their

use of benefits and social services. INS estimated that the number of illegal

aliens residing in the United States grew from 3.9 million in October 1992

to 5.0 million in October 1996.35 These estimates are difficult to use to

evaluate the impact of the strategy, however, because (1) they focus on

long-term illegal residents, rather than illegal aliens who come to the

United States for relatively short periods and return periodically to their

country of origin; (2) they do not allow for estimates of the extent to

which reductions in the flow of illegal immigration across the southwest

border may be offset by increases in aliens using legal nonimmigrant visas

but overstaying the terms of their visas; (3) they have so far been produced

too infrequently to be useful to evaluate short-term effects of enforcement

efforts; and (4) a shortage of information about some components of the

estimates makes it difficult to estimate the number of illegal aliens without

making questionable assumptions about these components. Some

additional data sources are available that could supplement INS data.

However, considerable effort and research would probably be entailed in

actually obtaining adequate estimates of the number of illegal aliens in the

United States.

There are numerous difficulties in accurately measuring the total number

of illegal aliens in the United States and in estimating how many illegal

aliens come to this country each year. One of the major difficulties arises

because of the heterogeneity of the illegal alien population. Some illegal

aliens, referred to as sojourners in the illegal immigration research

34Section 104 of the 1996 Act provides that as of April 1, 1998, “border-crossing identification cards,”

documents issued to permanent resident aliens or aliens living in a foreign bordering territory, include

a machine-readable biometric identifier, such as the fingerprint or handprint of the alien. The act

further mandates that by October 1, 1999, an alien presenting a border-crossing identification card is

not to be permitted to cross over the border into the United States unless the biometric identifier

contained on the card matches the appropriate biometric characteristic of the alien.

35In 1994, INS estimated that there were 3.4 million illegal aliens residing in the United States as of

October 1992. See: R. Warren, Estimates of the Unauthorized Immigrant Population Residing in the

United States, by Country of Origin and State of Residence: October 1992 (Washington, D.C.:

Immigration and Naturalization Service, 1994). INS revised the October 1992 estimate, based on new

data and improvements in methodology and published the October 1996 estimate in February 1997.

See INS Releases Updated Estimates of U.S. Illegal Population (Washington, D.C.: U.S. Immigration

and Naturalization Service News Release, February 1997).

Page 52 GAO/GGD-98-21 Illegal Immigation
B-276689 

literature, come to the United States on a temporary basis but consider

themselves residents of a foreign country and intend to return. Others,

referred to as settlers, come here with the intention of staying on a more

permanent basis. In addition, illegal aliens differ in their mode of arrival.

Some illegally cross the southwest border; enter illegally along other

borders; or enter illegally at the land, sea, or air ports of entry. Other aliens

enter legally with one of several types of visas and then fail to leave within

the allowed time period.

Border enforcement efforts may have different effects on each of these

groups, some of them not intended or anticipated in the Attorney

General’s strategy. For example, successful border enforcement may

result in sojourners limiting the number of trips they make to the United

States, but staying for longer periods of time, because of the greater

difficulty in crossing the border. In that case, successful border control

would effectively reduce the number of illegal border crossings but could

increase the average length of time that illegal aliens reside in the United

States. Successful border strategies may also discourage sojourners from

crossing the border illegally but may encourage them to try to enter legally

and stay longer than authorized. A comprehensive evaluation that seeks to

determine the effect of the strategy on the number of illegal aliens in the

United States would need to have reliable and valid data on sojourners and

settlers, and on those who enter legally as well as those who overstay. The

evaluation would also have to account for the impact of outside factors,

such as economic conditions in countries of origin and policy changes in

the United States.

In February 1997 INS released estimates of the overall stock of illegal aliens

residing in the United States in October 1996 and updated earlier estimates

that it had made for October 1992, using data collected by INS and the

Census Bureau. According to the latest estimates, 5 million illegal aliens

resided in the United States as of October 1996, up from 3.9 million as of

October 1992. These estimates are difficult to use to evaluate the impact of

enforcement efforts at the border, for a number of reasons. First,

individuals covered in these estimates are defined as those who have

established residence in the United States by remaining here illegally for

more than 12 months. The estimates therefore provide little information

about the number of sojourners who come to the United States and stay

for periods shorter than 1 year. Other kinds of data are needed to examine

the sojourner population.

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Second, uncertainty about the number of people who enter legally with

nonimmigrant visas and stay longer than authorized (overstays) makes it

difficult to assess whether a decrease in the estimated number of illegal

border crossers from Mexico due to border enforcement is offset by an

increase in Mexican overstays. The INS overstay estimates for 1996 contain

a projection based on earlier overstay data, thus the total estimate is

subject to considerable uncertainty. In recent testimony to Congress, INS

admitted that it has been unable to produce estimates of overstays since

1992.36 Indeed, because of problems with the data system on overstays,37

INS acknowledges that it is unable to estimate the current size of the

overstay problem and the magnitude by country of origin.38

Third, estimates made once every 4 years are not suited to identifying

intermediate trends that might signal effects of border enforcement

efforts. INS has calculated an average annual growth rate of 275,000 in the

illegal resident population between 1992 and 1996, but these estimates

result from averaging over 4 years and cannot distinguish yearly changes

in the illegal alien population.

Fourth, INS acknowledges that limited information about some

components of the estimates may increase uncertainty about the size of

the illegal population. For example, limited information about the extent

to which the Mexican-born population may be undercounted and the

number who emigrated from the United States during the period between

estimates necessitate assumptions that affect the precision of the

estimates of the illegal alien population.

Unfortunately, data are limited on the number of illegal alien sojourners

who travel back and forth between Mexico and the United States. The

Binational Study on Migration cited estimates from the previously

36Statement of Michael D. Cronin, Assistant Commissioner for Inspections, Immigration and

Naturalization Service, before the Subcommittee on Immigration and Claims, House Judiciary

Committee, June 17, 1997. See also: Office of the Inspector General, Immigration and Naturalization

Service Monitoring of Nonimmigrant Overstays (Washington, D.C.: U.S. Department of Justice,

September 1997).

37The overstay estimates are based on matched records from arrival forms, collected by INS, and

departure forms, collected primarily by airlines. The INS nonimmigrant overstay method estimates the

number of aliens, except students, who after being legally admitted have remained in the United States

longer than they have been authorized to stay. These individuals have been inspected by INS at

authorized ports of entry, and a record of their arrival is known to the government. Border crossers

from Canada and Mexico or crewmen who enter legally through inspection are not included.

38Section 110 of the 1996 Act requires INS by October 1, 1998, to develop an automated entry-exit

control system to enable the Attorney General to monitor all entries and exits at ports of entry. Until

such a system is in place, it is likely that considerable uncertainty about the magnitude of overstays

will remain.

Page 54 GAO/GGD-98-21 Illegal Immigation
B-276689 

mentioned Northern Border study of the number of both legal and illegal

sojourners traveling to the United States and returning to Mexico in 1993

and 1995. The study found a decrease between 1993 and 1995 in the overall

number of people traveling in each direction. The Binational Study

interpreted these findings to mean that sojourners were likely staying

longer in the United States in 1995 than in 1993. However, the study was

unable to distinguish the size of the illegal from the legal alien flow. The

Mexican Migration Project data have also been used to estimate changes

in net annual illegal migration from Mexico (subtracting estimates of the

number of illegal aliens who return to Mexico from estimates of the

number of illegal aliens who migrate to the United States). Because neither

study was based on data that represented all illegal aliens in the United

States, estimates derived from these studies may be most useful for

looking at trends, rather than absolute levels, of illegal immigration from

Mexico.

Finally, a number of existing data sources provide estimates of the number

of illegal aliens in United States workplaces. Since 1988, the U.S.

Department of Labor has administered its National Agricultural Workers

Survey 3 times a year to a random sample of the nation’s crop farm

workers and has asked respondents about their immigration status, among

other things. Such data may be useful for examining whether border

enforcement efforts have reduced the number, or proportion, of illegal

aliens in a sector that has traditionally attracted high proportions of illegal

migrants, and whether the characteristics of illegal aliens working in

agriculture have changed. An April 1997 report prepared for the U.S.

Commission on Immigration Reform, based on National Agricultural

Workers Survey data from 1988 to 1995, showed an increasing percentage

of illegal aliens in agriculture during this time period.39

Many illegal aliens work in sectors other than agriculture, including

urban-sector employment in construction and services.40 INS collects

statistics on the results of targeted and random investigations in U.S.

workplaces. Trends in the number of illegal aliens apprehended at the

workplace may reflect enforcement efforts at the southwest border. For

example, if recent border enforcement efforts are effective, the proportion

of apprehended illegal aliens who have recently arrived in the United

39R. Mines, S. Gabbard, & A. Steirman, A Profile of U.S. Farm Workers: Demographics, Household

Composition, Income and Use of Services, (Washington, D.C.: Prepared for the U.S. Commission on

Immigration Reform, April 1997).

40The Binational Study notes that there is evidence of a long-term upward trend in U.S. urban-sector

employment—particularly in construction and services—for illegal aliens.

Page 55 GAO/GGD-98-21 Illegal Immigation
B-276689 

States might decrease at various workplaces. However, changes in the

number of illegal aliens apprehended at U.S. workplaces may be a result of

other causes, such as greater emphasis by INS staff on investigating

whether employers are complying with the law and INS regulations

concerning aliens’ right to work in the United States.

INS Evaluation Efforts INS recognizes that multiple indicators are necessary, and, as part of its

fiscal year 1997 priority to strengthen border facilitation and control, INS

stated that it would “review past and current studies and initiatives

regarding measurements of success of both enforcement and facilitation

along the [Southwest] border.”41 An objective within this priority was to

make recommendations for appropriate measures and complete

implementation plans. However, INS was unable to provide us with any

documentation that it or any other Justice component was pursuing a

broader, formal evaluation of the southwest border strategy. In June 1997,

INS officials told us that they had completed a review of indicators used in

the past by INS and others, but had not yet made recommendations

regarding what measures would be collected, who would be responsible

for collecting the data, or how the data would be analyzed.

Along these lines, the Justice Department’s September 1997 Strategic Plan

stated that a key element in the Department’s strategic planning process is

the “systematic evaluation of major programs and initiatives.” Although

the strategic plan described program goals, strategies, and performance

indicators for INS, it did not contain a program evaluation component to

explain how it will assess success in meeting these goals and, in a broader

sense, the effectiveness of the southwest border strategy. Justice’s

strategic plan acknowledged that there has been relatively little formal

evaluation of its programs in recent years. According to the plan, Justice

intends to examine its current approach to evaluation to determine how to

better align evaluation with its strategic planning efforts.

Conclusions The Attorney General has a broad strategy for strengthening enforcement

of the Nation’s immigration laws that places priority on deterring illegal

entry into the United States along the southwest border. Congress has

been supporting efforts to gain control of the southwest border by

substantially increasing INS’ funding for enforcement activities. As a result,

41FY 97 Priority: Strengthen Border Facilitation and Control (Washington, D.C.: Immigration and

Naturalization Service, November 1996).

Page 56 GAO/GGD-98-21 Illegal Immigation
B-276689 

the Department of Justice and INS have made some strides in implementing

the strategy.

INS’ data on the effects of the implementation of the strategy indicate that a

number of the interim results anticipated by the Attorney General are

occurring. To comprehensively and systematically assess the effects of the

strategy over time, there are a variety of other indicators that may be

useful to provide information on some aspects of each of the results

envisioned by the strategy. INS has collected data and reported on some,

but not all, of these indicators.

Although Justice’s strategic plan recognizes the importance of systematic

evaluation of major initiatives, Justice has no comprehensive evaluation

plan for formally evaluating whether the strategy is achieving its intended

range of results—such as reducing flow across the border, reducing flow

to the border, and reducing the number of illegal aliens who reside in the

United States.

We recognize that developing a formal evaluation plan and implementing a

rigorous and systematic evaluation of the strategy could require a

substantial investment of resources, in part because the needed data may

not be presently available, thereby possibly requiring support for new data

collection efforts. Thus, devising such an evaluation plan should entail

determining the most important data needs and the most appropriate and

cost-effective data sources and data collection activities as well as

carefully analyzing the relationships among various indicators to correctly

interpret the results. Furthermore, data obtained on any set of indicators

should be interpreted in the context of economic conditions and policy

changes in the countries of origin of illegal immigrants and in the United

States to help ensure that the results are attributable to the strategy and

not to other potential causes.

Notwithstanding the challenges in devising such a broad-based evaluation

plan, we believe that the substantial investment of billions of dollars being

made in the Attorney General’s strategy warrants a cost-effective,

comprehensive evaluation to demonstrate whether benefits commensurate

to the investment have been realized. Such an evaluation would also be in

keeping with the concepts embodied in the Government Performance and

Results Act of 1993 as well as the Department’s strategic plan to evaluate

major initiatives.

Page 57 GAO/GGD-98-21 Illegal Immigation
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In addition, a comprehensive evaluation would also assist Justice in

identifying whether INS is implementing the strategy as planned; what

aspects of the strategy are most effective; and, if the strategy’s goals are

not being achieved, the reasons they are not. Such information would help

the agency and Congress identify whether changes are needed in the

strategy, in policy, in resource levels, or in program management.

Recommendations We recommend that the Attorney General develop and implement a plan

for a formal, cost-effective, comprehensive, systematic evaluation of the

strategy to deter illegal entry across the southwest border. This plan

should describe (1) the indicators that would be required for the

evaluation, (2) the data that need to be collected, (3) mechanisms for

collecting the data, (4) controls intended to ensure accuracy of the data

collected, (5) expected relationships among the indicators, and

(6) procedures for analyzing the data.

Agency Comments We requested comments on a draft of this report from the Attorney

General or her designees. On September 16, 1997, we met to obtain oral

comments on the draft report from the INS Executive Associate

Commissioner (EAC) for Policy and Planning and other officials from INS’

Office of Policy and Planning, Field Operations, Border Patrol,

Inspections, Intelligence, Budget, General Counsel, Internal Audit, and

Congressional Relations as well as from the Justice Management Division

and the Executive Office for United States Attorneys. INS and the

Executive Office for United States Attorneys followed up this discussion

with point sheets, which reiterated their oral comments suggesting

clarifications and technical changes. We also requested comments from

the Secretary of State and the Acting Commissioner of Customs. The

Customs Service had no comments on our draft report. We received

technical comments from the Department of State. We made clarifications

and technical changes to the draft report where appropriate.

Although INS chose not to provide written comments on the report or the

recommendation, INS officials told us that they recognize the need for a

comprehensive border-wide evaluation and are in the process of designing

and implementing one. The evaluation design was not available when we

finalized this report; therefore, we are not in a position to assess whether

it contains the types of evaluation factors discussed in our

recommendation.

Page 58 GAO/GGD-98-21 Illegal Immigation
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We are sending copies of this report to the Attorney General, the

Commissioner of the Immigration and Naturalization Service, the Acting

Commissioner of the U.S. Customs Service, the Secretary of State, the

Director of the Office of Management and Budget, and other interested

parties. We will also make copies available to others upon request.

If you or your staff have any questions concerning this report, please

contact me on (202) 512-8777. This report was done under the direction of

Evi L. Rezmovic, Assistant Director, Administration of Justice Issues.

Other major contributors are listed in Appendix VII.

Richard M. Stana

Acting Associate Director, Administration

 of Justice Issues

Page 59 GAO/GGD-98-21 Illegal Immigation
Contents

Letter 1

Appendix I 

Attorney General’s

Strategy to Deter

Illegal Entry Into the

United States Along

the Southwest Border

64

Border Patrol 64

Inspections at Ports of Entry 65

Prosecutions 66

Intelligence 67

Indicators of Success 67

Documents Used to Prepare Analysis 68

Appendix II 

Status of Selected

Border Enforcement

Initiatives Mandated

by the 1996 Act

70

Improvement in the Border-Crossing Identification Card 70

New Civil Penalties for Illegal Entry 71

New Automated Entry/Exit Control System 71

Appendix III 

INS Border Patrol and

Inspections Staffing

and Selected

Workload Data

73

Appendix IV 

Expert Panel

Participants

79

Page 60 GAO/GGD-98-21 Illegal Immigation
Contents

Appendix V 

Indicators for

Measuring the

Effectiveness of the

Strategy to Deter

Illegal Entry Along the

Southwest Border

80

Appendix VI 

Description of

Selected Immigration

Research Projects

91

The Mexican Migration Project 91

The Zapata Canyon Project 93

Survey of Migration to the Northern Border 94

The United States-Mexico Binational Study on Migration 95

Appendix VII 

Major Contributors to

This Report

97

Bibliography 98

Related GAO Products 104

Tables Table 1: Status of Barriers Along the Southwest Border 20

Table III.1: Authorized Border Patrol Agent Positions in

Southwest Border Patrol Sectors, Fiscal Years 1993 - 1997

73

Table III.2: Apprehensions by Southwest Border-Patrol Sector,

Fiscal Year 1992 Through First Half of Fiscal Year 1997

73

Table III.3: Border Patrol Hours by Southwest Border Patrol

Sector, Fiscal Year 1992 Through First Half Fiscal Year 1997

74

Table III.4: Authorized Inspector Positions by Land Ports of Entry

and INS District Offices Along the Southwest Border, Fiscal

Years 1994 - 1997

76

Table III.5: INS Inspections, Selected Workload and Enforcement

Data by Southwest Border District Offices, Fiscal Year 1994

Through First Half Fiscal Year 1997

77

Page 61 GAO/GGD-98-21 Illegal Immigation
Contents

Figures Figure 1: INS Regions and Border Patrol Sector Headquarters

Along the Southwest Border

6

Figure 2: INS Land Ports of Entry Along the Southwest Border 8

Figure 3: Allocation of New Agent Positions by Southwest Border

Patrol Sector, Fiscal Years 1994 Through 1997

15

Figure 4: Number of On-Board Agents by Southwest Border

Patrol Sector, October 1993 Compared with July 1997

16

Figure 5: Bollard Fencing Being Constructed in San Diego,

California

19

Figure 6: Percentage of Agents’ Time Spent on Border

Enforcement by Southwest Border Sector, Fiscal Year 1994

Compared with First Half of Fiscal Year 1997

22

Figure 7: Allocation of New Inspectors to Land Ports of Entry

Along the Southwest Border by INS District Office, Fiscal Years

1994 through 1997

25

Figure 8: Number of On-Board Inspectors at Land Ports of Entry

Along the Southwest Border by INS District Office, September

1994 Compared With March 1997

26

Figure 9: Apprehensions (seasonally adjusted) in the San Diego

Border Patrol Sector, October 1992 to March 1997

32

Figure 10: Apprehensions (seasonally adjusted) in the El Paso

Border Patrol Sector, October 1992 to March 1997

34

Figure 11: Apprehensions in San Diego, El Paso, and Other

Southwest Border Patrol Sectors, First Half of Fiscal Years 1993

and 1997

35

Figure 12: Apprehensions by Border Patrol Stations in the San

Diego Sector, First Half of Fiscal Years 1993 and 1997

36

Figure 13: Apprehensions by Border Patrol Station in the El Paso

Sector, First Half of Fiscal Years 1993 and 1997

38

Figure 14: Apprehensions by Border Patrol Station in the Tucson

Sector, First Half of Fiscal Years 1993 and 1997

39

Page 62 GAO/GGD-98-21 Illegal Immigation
Contents

Abbreviations

COLEF Colegio de la Frontera Norte

EAC Executive Associate Commissioner

EOIR Executive Office of Immigration Review

CLASS Consular Lookout and Support System

INS Immigration and Naturalization Service

IRCA Immigration Reform and Control Act

MMP Mexican Migration Project

NAWS National Agricultural Workers Survey

OIG Office of Inspector General

POE Port of Entry

PQIC Port Quality Improvement Committees

SAWS Seasonal Agricultural Workers Survey

Page 63 GAO/GGD-98-21 Illegal Immigation
Appendix I 

Attorney General’s Strategy to Deter Illegal

Entry Into the United States Along the

Southwest Border

In February 1994, the Attorney General and Immigration and

Naturalization Service (INS) Commissioner announced a comprehensive

five-part strategy to strengthen enforcement of the nation’s immigration

laws. The strategy outlined efforts to curb illegal entry and protect legal

immigration by focusing on five initiatives: (1) strengthening the border;

(2) removing criminal aliens; (3) reforming the asylum process;

(4) enforcing workplace immigration laws; and (5) promoting citizenship

for qualified immigrants. The first priority, strengthening the border,

focused on immigration control efforts along the 2,000-mile U.S.-Mexican

border and is summarized here.

According to the 1994 strategy announced by the Attorney General and the

INS Commissioner, the first priority was to focus on the areas between the

ports of entry, which are divided into nine Border Patrol sectors.

Recognizing the displacement effect of enhanced efforts between the ports

of entry, the ports of entry along the southwest border were added to

provide comprehensive coverage, and thus compensate for displacement.

The new border strategy involved “prevention through deterrence.” This

strategy called for concentrating new resources on the front lines at the

most active points of illegal entry along the southwest border.

The key objectives of the between-the-ports strategy were to (1) close off

the routes most frequently used by smugglers and illegal aliens (generally

through urban areas) and (2) shift traffic through the ports of entry or over

areas that were more remote and difficult to cross illegally, where INS had

the tactical advantage. To carry out this strategy, INS planned to provide

the Border Patrol and other INS enforcement divisions with the personnel,

equipment, and technology to deter, detect, and apprehend illegal aliens.

INS also had related objectives of preventing illegal entry through the ports,

increasing prosecutions of smugglers and aliens who repeatedly enter the

United States illegally, and improving the intelligence available to border

patrol agents and port inspectors.

Border Patrol In July 1994, the Border Patrol developed its own plan to carry out the

Attorney General’s between-the-ports strategy. The plan, still current in

September 1997, was to maximize the risk of apprehension, using

increased human and physical barriers to entry to make passage more

difficult so that many will consider it futile to continue to attempt illegal

entry through traditional routes. Consistent with the Attorney General’s

strategy, the Border Patrol sought to bring a decisive number of

Page 64 GAO/GGD-98-21 Illegal Immigation
Appendix I 

Attorney General’s Strategy to Deter Illegal

Entry Into the United States Along the

Southwest Border

enforcement resources to bear in each major entry corridor so that illegal

aliens would be deterred from using traditional corridors of entry.

The plan called for targeting resources to the areas of greatest illegal

activity in four phases:

• Phase I -Concentrate efforts in San Diego (Operation Gatekeeper) and El

Paso (Operation Hold-the-Line), since these two areas historically

accounted for 65 percent of all apprehensions along the southwest border,

and contain displacement effects in the El Centro and Tucson sectors.

• Phase II -Control the Tucson and south Texas corridors.

• Phase III -Control the remainder of the southwest border.

• Phase IV -Control all other areas outside the southwest border, and

concentrate on the northern border and water avenues (for example,

Pacific and Gulf coasts).

The Border Patrol strategic plan directed intense enforcement efforts at

the areas of greatest illegal activity. This strategy differed from the

previous practice of thinly allocating Border Patrol agents along the

border as new resources became available. Each southwest sector

developed its own tactical plan detailing how it would implement the

Border Patrol’s strategic plan. According to the plan, each sector was to

focus first on controlling urban areas and increase the percentage of

border-control hours on the front lines of the border in such duties as

linewatch,1

 patrol, checkpoints, and air operations.

Inspections at Ports of

Entry

To complement the Border Patrol’s strategic plan, which will be carried

out between the ports of entry, INS Inspections developed Operations

2000+ in September 1996 to enhance operations at the ports of entry. This

plan called for increasing the identification and interception of criminals

and illegal entrants. To accommodate legal entry while enhancing its

efforts to deter illegal entry at the ports of entry, INS will increase its use of

technology to improve management of legal traffic and commerce. As part

of this effort, INS had several pilot projects ongoing to use dedicated

commuter lanes and automated entry systems to speed the flow of

frequent low-risk travelers through the ports. The use of automated

systems could then free inspectors’ time to be spent on other enforcement

activities.

1

Patrolling the immediate border area.

Page 65 GAO/GGD-98-21 Illegal Immigation
Appendix I 

Attorney General’s Strategy to Deter Illegal

Entry Into the United States Along the

Southwest Border

Prosecutions In concert with INS’ efforts to deter illegal entry, the Attorney General

seeks to increase prosecutions of alien smugglers, coyotes,2

 and those

with criminal records who repeatedly reenter the United States after

having been removed. This program involves several aspects regarding the

federal prosecution function and is intended

• to develop, through the U.S. Attorneys in the five judicial districts

contiguous to the U.S.-Mexico border, federal prosecution policies to

(1) support enforcement strategies implemented at the ports of entry by

INS and U.S. Customs and between the ports by the Border Patrol,

(2) maximize crime reduction in border communities, (3) minimize

border-related violence, and (4) engender respect for the rule of law at the

border. These policies include (1) targeting criminal aliens for 8 U.S.C.

13263

 prosecution, (2) targeting coyotes to disrupt the smuggling

infrastructure, (3) increasing alien smuggling prosecutions, (4) increasing

false document vendor prosecutions, (5) enforcing civil rights laws,

(6) prosecuting assaults against federal officers, and (7) prosecuting

border-related corruption cases.

• to coordinate the use of INS/Executive Office of Immigration Review (EOIR)

administrative sanctions and the application of federal criminal sanctions

to achieve an integrated and cost-effective approach to the goal of

deterrence in border law enforcement. This step includes (1) enforcing

EOIR orders as predicates for federal prosecution under section 1326, and

(2) using INS/EOIR removal orders and section 1326 provisions to prosecute

coyotes.

• to enhance cooperation between federal immigration authorities and state

and local law enforcement agencies to (1) leverage INS enforcement efforts

through coordination with local law enforcement as allowed by law;

(2) identify arrestees’ immigration status to facilitate choice at the outset

of official processing among the options of administrative sanctioning,

federal criminal prosecution, and state criminal prosecutions; and

(3) ensure removal by immigration authorities of criminal aliens from the

country, following service of state and local sentences after conviction.

This plan involves (1) instituting county jail programs, (2) employing state

and local police to supplement INS personnel, (3) allocating cases

effectively between federal and state prosecutors, and (4) integrating

information/identification systems among jurisdictions.

The Attorney General designated the U.S. Attorney for the Southern

District of California as her Southwest border representative and directed

2

Foot guides.

3

Statute providing criminal penalties for reentry of certain deported aliens.

Page 66 GAO/GGD-98-21 Illegal Immigation
Appendix I 

Attorney General’s Strategy to Deter Illegal

Entry Into the United States Along the

Southwest Border

him to coordinate the border law enforcement responsibilities of various

Justice Department agencies—including INS, the Drug Enforcement

Agency, and the Federal Bureau of Investigation—with activities

undertaken by the Treasury Department and the Department of Defense.

Intelligence Another part of the strategy to deter illegal entry across the Southwest

border was to reengineer INS’ Intelligence program so the border patrol

agents and port inspectors could better anticipate and respond to changes

in illegal entry and smuggling patterns. By the end of fiscal year 1997, INS

expected to have an approved strategic plan for collecting and reporting

intelligence information, integrating additional assets into the Intelligence

program, and assessing field intelligence requirements. In addition,

intelligence training and standard operating procedures for district and

sector personnel were to be developed.

Indicators of Success As the strategy is being carried out, the Department anticipates that its

success will be measurable using more indicators than the one

traditionally used: apprehensions. The Department anticipates the

following measurable results to occur:

• an initial increase in arrests between the ports and then an eventual

reduction of arrests and recidivism in traditional corridors;

• shift in the flow of illegal alien entries from the most frequent routes

(generally through urban areas) to more remote areas;

• increased port-of-entry activities, including increased entry attempts and

increased use of fraudulent documents;

• increased instances of more sophisticated methods of smuggling at

checkpoints;

• increased fees charged by smugglers;

• increased numbers of criminal aliens prosecuted for entering the country

illegally;

• increased numbers of alien smugglers, coyotes, and false document

vendors prosecuted;

• increased numbers of deportations of people presenting false documents;

and,

• reduced violence at the border (for example, less instances of border

banditry).

Further, although the Department will not be able to measure them and

many complex variables other than border enforcement affect them, the

Page 67 GAO/GGD-98-21 Illegal Immigation
Appendix I 

Attorney General’s Strategy to Deter Illegal

Entry Into the United States Along the

Southwest Border

Department believes its enhanced enforcement activities will have a

positive impact on the following:

• fewer illegal immigrants in the interior of the United States and

• reduction in the use of social services and benefits by illegal aliens in the

United States.

Documents Used to

Prepare Analysis

The following documents, listed in chronological order, were used to

prepare our summary of the Attorney General’s strategy to deter illegal

entry into the U.S. along the Southwest border:

Department of Justice, Attorney General and INS Commissioner Announce

Two-Year Strategy to Curb Illegal Immigration, Press Release, February 3,

1994.

U.S. Government Printing Office, Accepting the Immigration Challenge,

The President’s Report on Immigration, 1994.

INS, Strategic Plan: Toward INS 2000, Accepting the Challenge, November 2,

1994.

INS, Border Patrol Strategic Plan 1994 and Beyond, National Strategy, U.S.

Border Patrol, July 1994.

INS, Priority 2: Strengthen Border Enforcement and Facilitation, Fiscal

Year 1996 Priority Implementation Plan.

Department of Justice, Executive Office for United States Attorneys, USA

Bulletin, Vol. 44, Number 2, April 1996.

Department of Justice, INS, Building a Comprehensive Southwest Border

Enforcement Strategy, June 1996.

Department of Justice, INS, Meeting the Challenge Through Innovation,

September 1996.

INS Office of Inspections, Inspections 2000+: A Strategic Framework for

the Inspections Program, September 1996.

Illegal Immigration Reform and Immigrant Responsibility Act of 1996.

Page 68 GAO/GGD-98-21 Illegal Immigation
Appendix I 

Attorney General’s Strategy to Deter Illegal

Entry Into the United States Along the

Southwest Border

INS, Operation Gatekeeper, Two Years of Progress, October 1996.

INS, Strengthen Border Facilitation and Control, Fiscal Year 1997 Priorities.

Department of Justice, INS, Immigration Enforcement, Meeting the

Challenge, A Record of Progress, January 1997.

In addition, we reviewed the strategies prepared in 1994 by the Border

Patrol’s nine southwest border sectors.

Page 69 GAO/GGD-98-21 Illegal Immigation
Appendix II 

Status of Selected Border Enforcement

Initiatives Mandated by the 1996 Act

Subtitle A, Title I of the 1996 Act mandates further improvements in

border-control operations. These include improvement in the

border-crossing identification card, new civil penalties for illegal entry or

attempted entry, and a new automated entry/exit control system. The

status of initiatives to address these provisions is discussed below.

Improvement in the

Border-Crossing

Identification Card

Section 104 of the 1996 Act provides that documents issued on or after

April 1, 1998, bearing the designation “border-crossing identification

cards” include a machine-readable biometric identifier, such as the

fingerprint or handprint of the alien. The 1996 Act further mandates that

by October 1, 1999, an alien presenting a border-crossing identification

card is not to be permitted to cross over the border into the United States

unless the biometric identifier contained on the card matches the

appropriate biometric characteristic of the alien.

According to INS Inspections officials, as of September 1997, initiatives to

implement this provision were under way, but several issues had yet to be

resolved. An INS official told us that INS and the State Department have

reached a mutual decision on the biometric characteristics to be used on

the card. A digitized color photograph, with potential use for facial

recognition as that technology advances, will be collected. Live scan prints

of both index fingers will also be collected. These fingerprints are

compatible with IDENT, INS’ automated fingerprint identification system.

However, the system to be used to verify this information at the point of

entry into the United States had not been determined. According to the

official, resolution of this problem is necessary since currently no viable

technology available can implement what the law requires. INS plans to

pilot test a biometric card for pedestrians at the Hidalgo, Texas port of

entry by the end of calendar year 1997.

The new system would also change which federal agency provides

border-crossing cards and which agency produces the cards as well as

where the cards are available. Currently, INS Immigration Inspectors at

ports of entry and some State Department consular officers adjudicate

applications and issue border-crossing cards. The INS Commissioner and

the Assistant Secretary of State for Consular Affairs, on September 9 and

September 18, 1997, respectively, signed a memorandum of understanding

on how the revised border-crossing card process would work. Under the

new system, the State Department will take over all adjudication of these

cards. Foreign services posts will collect the fees and necessary data,

including the biometric, and will send the data electronically to INS. INS will

Page 70 GAO/GGD-98-21 Illegal Immigation
Appendix II 

Status of Selected Border Enforcement

Initiatives Mandated by the 1996 Act

produce the cards. According to a State Department official, consular

officers will check border-crossing card applicants against the State

Department’s Consular Lookout and Support System (CLASS)1

 to identify

those that may be ineligible. The actual details of how the system will

operate are, however, still being worked out, e.g., how to handle the

volume of applicants. INS officials said that if all goes as expected, the new

process will be in place on April 1, 1998.

New Civil Penalties

for Illegal Entry

Section 105 of the 1996 Act mandates new civil penalties for illegal entry.

Any alien apprehended while entering (or attempting to enter) the United

States at a time or place other than as designated by immigration officers

is subject to a civil penalty of at least $50 and not more than $250 for each

such entry or attempted entry. The penalty is doubled for an alien who has

been previously subject to a civil penalty under this subsection. Moreover,

such penalties are in addition to, not instead of, any criminal or other civil

penalties that may be imposed. This provision applies to illegal entries or

attempts to enter occurring on or after April 1, 1997.

As of September 1997, INS was still studying this issue. According to an INS

official, a working group met in April 1997 and prepared an option papers

for INS’ Policy Council. Based on this preliminary analysis, the council

concluded that the program’s administration would probably cost more

than the fines collected and the fines would not deter individuals, since

few individuals would have the money to pay the fines. Accordingly, the

INS Policy Council requested further study of the potential effects of the

program before proceeding further with implementation. Such a study was

on-going as of September 1997. No deadline was set for the study. Further

development of the rules and regulations required to implement the

program will depend on the results of the study.

New Automated

Entry/Exit Control

System

Section 110 of the 1996 Act directs the Attorney General to develop an

automated entry and exit control system by October 1, 1998, to (1) collect

data on each alien departing the United States and match the record of

departure with that of the alien’s arrival in the United States and (2) enable

the Attorney General to identify through on-line searching procedures,

lawfully admitted nonimmigrants who remain in the United States beyond

the time authorized.

1

CLASS is the State Department’s name-check system, which contains information on foreign nationals

who may apply for visas to the United States.

Page 71 GAO/GGD-98-21 Illegal Immigation
Appendix II 

Status of Selected Border Enforcement

Initiatives Mandated by the 1996 Act

According to INS Inspections officials, this system is in the early

development stage. INS is pilot testing a system for air travelers and

believes it will have a system in place for them within the 2-year mandated

time period.

However, many implementation issues remain regarding travelers who

enter and exit across the land borders. For example, how will exit control

be done for those driving across the land borders? Will everyone entering

the United States, including citizens, be checked? If so, how do you check

everyone? If not, how do you know who is an alien and who is not? INS

expects to test a pilot project for an arrival/departure system for

pedestrian crossers at the Eagle Pass, Texas land port of entry. According

to INS Inspections officials, INS plans to ask Congress for more time to

implement such as a system at land ports of entry, but had not done so as

of September 1997. At that time, INS had at the Office of Management and

Budget a technical amendment requesting more time to implement the

system for land ports of entry.

Officials also indicated that there is some concern regarding different

mandates in the 1996 Act. For example, while the act specifies that the

biometric is for the border-crossing card, the provision mandating the

automated entry/exit system includes no mention of using a biometric.

Page 72 GAO/GGD-98-21 Illegal Immigation
Appendix III 

INS Border Patrol and Inspections Staffing

and Selected Workload Data

Table III.1: Authorized Border Patrol Agent Positions in Southwest Border Patrol Sectors, Fiscal Years 1993 - 1997

Authorized increases each year Total increase

Border Patrol Sector

Authorized

Agents

FY 93a FY 94 FY 95 FY 96 FY 97 FY 94-97 Percent

Total

Authorized

agents FY 97

San Diego 980 300 229 428 278 1235 44 2215

El Centro 194 0 0 0 50 50 2 244

Yuma 178 0 0 0 0 0 0 178

Tucson 281 0 128 246 228 602 21 883

El Paso 602 50 93 101 107 351 12 953

Marfa 131 0 0 0 0 0 0 131

Del Rio 290 0 100 0 52 152 5 442

Laredo 347 0 75 0 49 124 4 471

McAllen 386 0 75 25 228 328 12 714

Total Southwest

Border

3389 350 700 800 992b 2842 100 6231

aAccording to INS officials, the number of on-board agents as of September 30, 1993, is

considered as fiscal year 1993 authorized border patrol staffing levels for comparison purposes.

bDoes not include eight agents deployed to Puerto Rico for the Attorney General’s Puerto Rico

Anti-Crime initiative.

Source: INS.

Table III.2: Apprehensions by Southwest Border-Patrol Sector, Fiscal Year 1992 Through First Half of Fiscal Year 1997

Border Patrol

sector FY 92 FY 93 FY 94 FY 95 FY 96 First half FY 97

San Diego 565,581 531,689 450,152 524,231 483,815 172,339

El Centro 29,852 30,058 27,654 37,317 66,873 57,438

Yuma 24,892 23,548 21,211 20,894 28,310 15,376

Tucson 71,036 92,639 139,473 227,529 305,348 140,077

El Paso 248,642 285,781 79,688 110,971 145,929 69,362

Marfa 13,819 15,486 13,494 11,552 13,214 6,622

Del Rio 33,414 42,289 50,036 76,490 121,137 61,567

Laredo 72,449 82,348 73,142 93,305 131,841 75,475

McAllen 85,889 109,048 124,251 169,101 210,553 131,643

Total southwest

border

1,145,574 1,212,886 979,101 1,271,390 1,507,020 729,899

Source: INS.

Page 73 GAO/GGD-98-21 Illegal Immigation
Appendix III 

INS Border Patrol and Inspections Staffing

and Selected Workload Data

Table III.3: Border Patrol Hours by Southwest Border Patrol Sector, Fiscal Year 1992 Through First Half Fiscal Year 1997

Border Patrol Sector FY 92 FY 93 FY 94 FY 95 FY 96 First half FY 97

San Diego

General enforcement 55,687 59,050 72,240 43,884 26,695 7,457

Program support 720,097 917,149 933,549 1,030,319 1,255,970 766,895

Border enforcement 866,500 1,067,872 1,004,232 1,361,983 1,756,647 1,021,266

Total 1,642,284 2,044,071 2,010,021 2,436,186 3,039,312 1,795,618

El Centro

General enforcement 27,619 27,396 24,871 19,252 14,648 5,376

Program support 139,131 149,095 138,529 143,259 148,241 73,628

Border enforcement 280,491 246,289 249,180 248,206 251,101 109,240

Total 447,241 422,780 412,580 410,717 413,990 188,244

Yuma

General enforcement 33,772 34,645 29,259 20,087 16,511 5,100

Program support 94,731 104,368 102,467 112,633 105,227 51,941

Border enforcement 279,030 255,330 258,137 249,374 257,871 118,558

Total 407,533 394,343 389,863 382,094 379,609 175,599

Tucson

General enforcement 21,898 25,418 20,756 15,768 17,557 5,513

Program support 219,951 264,022 250,294 316,267 395,867 305,885

Border enforcement 295,429 315,541 344,813 365,489 500,349 298,793

Total 537,278 604,981 615,863 697,524 913,773 610,191

El Paso

General enforcement 88,711 84,074 37,365 50,331 34,967 17,318

Program support 391,691 414,460 273,088 361,939 477,792 268,626

Border enforcement 707,507 809,921 1,023,146 964,533 1,028,846 516,186

Total 1,187,909 1,308,455 1,333,599 1,376,803 1,541,605 802,130

Marfa

General enforcement 63,492 46,467 42,755 36,854 13,757 2,003

Program support 89,312 99,873 93,757 89,693 91,170 40,558

Border enforcement 168,120 172,732 173,084 167,585 157,773 83,746

Total 320,924 319,072 309,596 294,132 262,700 126,307

(continued)

Page 74 GAO/GGD-98-21 Illegal Immigation
Appendix III 

INS Border Patrol and Inspections Staffing

and Selected Workload Data

Border Patrol Sector FY 92 FY 93 FY 94 FY 95 FY 96 First half FY 97

Del Rio

General enforcement 57,079 30,854 26,073 22,077 17,742 3,456

Program support 217,709 226,377 222,617 233,946 310,483 160,515

Border enforcement 453,309 396,972 382,607 399,761 501,760 252,388

Total 728,097 654,203 631,297 655,784 829,985 416,359

Laredo

General enforcement 30,279 25,342 24,199 19,884 19,664 6,036

Program support 182,963 188,928 165,711 75,005 210,034 105,349

Border enforcement 485,064 566,219 568,169 536,463 615,189 317,902

Total 698,306 780,489 758,079 731,352 844,887 429,287

McAllen

General enforcement 40,662 47,543 45,016 39,511 23,261 10,395

Program support 279,164 358,910 355,743 353,511 418,905 214,308

Border enforcement 378,562 482,576 470,671 470,868 551,726 274,431

Total 698,388 889,029 871,430 863,890 993,892 499,134

Southwest

Border

General enforcement 419,199 380,789 322,534 267,648 184,802 62,654

Program support 2,334,749 2,723,182 2,535,755 2,816,572 3,413,689 1,987,705

Border enforcement 3,914,012 4,313,452 4,474,039 4,764,262 5,621,262 2,992,510

Total 6,667,960 7,417,423 7,522,360 7,848,482 9,219,753 5,042,869

Note: General Enforcement includes duties indirectly related to deterrence, detection, and

apprehensions of illegal aliens, such as employer sanctions, criminal aliens and antismuggling

activities. Program Support includes hours that support enforcement duties such as, air

operations, intelligence, administrative/supervisory, special operations and training. Border

Enforcement includes duties directly related to the deterrence, detection and apprehension of

illegal aliens and interdiction of drugs and other contraband along the border, such as patrolling

the immediate border area, traffic check, transportation check, and boat and air patrol.

Source: INS.

Page 75 GAO/GGD-98-21 Illegal Immigation
Appendix III 

INS Border Patrol and Inspections Staffing

and Selected Workload Data

Table III.4: Authorized Inspector Positions by Land Ports of Entry and INS District Offices Along the Southwest Border,

Fiscal Years 1994 - 1997

Authorized increases each year

Total

authorized

inspectors INS district and land ports of

entry

Authorized

inspectors

FY 94 FY 95 FY 96a FY 97

Total

increase

FY 95-97 Percent FY 97

San Diego District 301 64 220 80 364 46 665

San Ysidro (2) 199 64 142 24

Tecate 4 0 19 0

Calexico 94 0 45 48

Andrade 4 0 14 8

Phoenix District 104 8 106 8 122 15 226

San Luis 20 0 11 5

Sasabe 3 0 15 0

Nogales (2) 57b 8 33 0

Naco 5 0 13 0

Lukeville 4 0 20 0

Douglas 15 0 14 3

El Paso District 163 11 108 0 119 15 282

Columbus 8 0 4 0

Santa Teresa 0 0 10 0

El Paso (2) 134b 11 65 0

Fabens 7 0 5 0

Fort Hancock 3 0 1 0

Presidio 11 0 8 0

Ysleta 0 0 15 0

San Antonio District 143 6 56 14 76 10 219

Laredo (3) 93b 6 42 5

Eagle Pass 26 0 7 6

Del Rio (2) 24 0 7 3

Harlingen District 158 21 46 48 115 14 273

Roma 24 0 2 0

Rio Grande City 0 0 2 6

Progresso 19 0 6 0

Pharr 7 0 6 4

Los Indios 0 0 1 6

Los Ebanos 0 0 2 1

Hidalgo 46 0 12 4

Falcoln Heights 0 0 0 3

Brownsville (2) 62b 21 15 24

(continued)

Page 76 GAO/GGD-98-21 Illegal Immigation
Appendix III 

INS Border Patrol and Inspections Staffing

and Selected Workload Data

Authorized increases each year

Total

authorized

inspectors INS district and land ports of

entry

Authorized

inspectors

FY 94 FY 95 FY 96a FY 97

Total

increase

FY 95-97 Percent FY 97

Total southwest border 869 110 536 150 796 100 1665

Note: Some locations have more than one port of entry.

aIncludes 136 inspector positions authorized in fiscal year 1994 and funded by land-border fees.

According to INS officials, these inspectors were not hired until fiscal year 1996, due to delays in

getting land-border fee regulations finalized.

bIncludes one staff assigned to the district office.

Source: INS.

Table III.5: INS Inspections, Selected Workload and Enforcement Data by Southwest Border District Offices, Fiscal Year

1994 Through First Half Fiscal Year 1997

INS District Office FY 94 FY 95 FY 96 First half FY 97

San Diego

U.S. citizens inspecteda 28,808,845 26,776,081 26,342,930 14,249,519

Aliens inspecteda 63,152,638 59,387,840 57,278,208 30,065,972

Total persons inspecteda 91,961,483 86,163,921 83,621,138 44,315,491

Pedestrians inspected 16,744,829 19,420,202 9,969,126

Vehicles inspected 28,094,028 26,152,680 13,941,527

Fraudulent documents intercepted 41,974 46,515 41,221 20,270

Oral false claims to U.S. citizenship 15,403 19,368 12,633 5,292

Individuals smuggled 6,565 5,377 6,581 4,207

Phoenix

U.S. citizens inspecteda 11,717,738 8,299,518 8,313,959 4,332,991

Aliens inspecteda 23,268,288 23,072,110 23,035,160 11,897,583

Total persons inspecteda 34,986,026 31,371,628 31,349,119 16,230,574

Pedestrians inspected 7,806,361 7,657,480 9,969,126

Vehicles inspected 8,951,615 8,984,091 13,941,527

Fraudulent documents intercepted 7,599 6,367 5,338 3,003

Oral false claims to U.S. citizenship 825 686 772 500

Individuals smuggled 279 253 427 241

El Paso

U.S. citizens inspecteda 27,230,751 24,975,450 22,481,928 11,180,053

Aliens inspecteda 42,033,208 39,821,598 36,339,994 18,248,564

Total persons inspecteda 69,263,959 64,797,048 58,821,922 29,428,617

Pedestrians inspected 4,578,798 4,571,073 2,213,165

(continued)

Page 77 GAO/GGD-98-21 Illegal Immigation
Appendix III 

INS Border Patrol and Inspections Staffing

and Selected Workload Data

INS District Office FY 94 FY 95 FY 96 First half FY 97

Vehicles inspected 18,143,401 17,529,375 8,833,279

Fraudulent documents intercepted 8,173 8,754 11,034 6,720

Oral false claims to U.S. citizenship 4,567 5,887 6,725 4,092

Individuals smuggled 751 599 611 388

San Antonio

U.S. citizens inspecteda 18,668,021 13,979,554 14,355,119 7,379,551

Aliens inspecteda 39,567,895 41,165,203 39,708,171 21,462,035

Total persons inspecteda 58,235,916 55144,757 54,063,290 28,841,586

Pedestrians inspected 7,289,530 5,219,599 2,914,118

Vehicles inspected 11,454,275 13,026,781 6,383,029

Fraudulent documents intercepted 6,338 6,100 7,636 5,040

Oral false claims to U.S. citizenship 1,467 1,284 1,541 1,008

Individuals smuggled 1,559 1,224 1,349 706

Harlingen

U.S. Citizens inspecteda 20,831,853 12,920,985 12,849,749 7,073,072

Aliens inspecteda 40,564,252 39,536,870 40,258,253 20,735,209

Total persons inspecteda 61,396,105 52,457,855 53,108,002 27,808,281

Pedestrians inspected 7,348,097 1,943,636 4,189,713

Vehicles inspected 14,412,630 15,195,266 7,811,192

Fraudulent documents intercepted 9,176 7,100 9,681 5,386

Oral false claims to U.S. citizenship 1,264 1,549 1,702 773

Individuals smuggled 1,394 897 1,299 762

Southwest Border

U.S. citizens inspecteda 107,257,208 86,951,588 84,343,685 44,215,186

Aliens inspecteda 208,586,281 202,983,621 196,619,786 102,409,363

Total persons inspecteda 315,843,489 289,935,209 280,963,471 146,624,549

Pedestrians inspected 43,767,615 44,811,990 23,824,075

Vehicles inspected 81,055,949 80,888,193 41,553,145

Fraudulent documents intercepted 73,260 74,836 74,910 40,419

Oral false claims to U.S. citizenship 23,526 28,774 23,373 11,615

Individuals smuggled 10,548 8,350 10,267 6,304

aEstimate based on periodic sampling of the number of occupants per vehicles entering the port

of entry.

Source: INS.

Page 78 GAO/GGD-98-21 Illegal Immigation
Appendix IV 

Expert Panel Participants

The following experts in research on illegal immigration issues paticipated

in a panel discussion held at GAO in Washington, D.C. on March 28, 1997.

They also reviewed portions of the draft report.

Deborah Cobb-Clark

Professor of Economics

Research School of Social Sciences

The Australian National University

Canberra, Australia

Sherrie Kossoudji

Professor of Economics

The School of Social Work

University of Michigan

Ann Arbor, MI

B. Lindsay Lowell

Director of Policy Research

U.S. Commission on Immigration Reform

Washington, D.C.

Philip Martin

Professor of Economics

Department of Agricultural and Resource Economics

University of California, Davis

Davis, CA

Douglas Massey

Professor of Sociology

Population Studies Center

University of Pennsylvania

Philadelphia, PA

Page 79 GAO/GGD-98-21 Illegal Immigation
Appendix V 

Indicators for Measuring the Effectiveness

of the Strategy to Deter Illegal Entry Along

the Southwest Border

Indicator Source of data

Predicted outcome if AG’s

strategy is successful

A. Flow across the Southwest border

Border Patrol apprehensions. INS 1. Displacement of flow in

accordance with Border

Patrol strategy.

2. Increasing apprehensions

at first; eventual reductions

as control is gained.

Detection of illegal aliens

crossing the border.

Number of “gotaways.”

Border Patrol sector data:

1. Sensor hits.

2. Sign cuts.

3. Infrared and low-light

television cameras.

Fewer aliens detected.

Fewer “gotaways.”

Recidivism (repeat

apprehensions of aliens).

INS IDENT system. Attempted reentries will

decrease over time.

Probability of apprehension.

Difficulty in crossing border.

Multiple sources:

1. IDENT recidivism data.

2. Mexican Migration

Project (MMP) provides

annual data from Mexican

migrants on the number of

times they were captured

on trips to the U.S. and

places where they were

apprehended.

3. Colegio de la Frontera

Norte (COLEF) surveys of

border crossers (Zapata

Canyon Project and Survey

of Migration to the Northern

Border).

4. Focus group interviews in

Mexico (Binational Study on

Migration).

An increase in the probability

of apprehension.

Page 80 GAO/GGD-98-21 Illegal Immigation
Appendix V 

Indicators for Measuring the Effectiveness

of the Strategy to Deter Illegal Entry Along

the Southwest Border

Findings Limitations

Is indicator currently being

measured?

Are there plans to measure

indicator on ongoing basis?

Mixed (see letter). 1. Measures event, not individuals.

2. Unclear relationship to actual

flow of illegal aliens.

3. No information on those aliens

who elude capture.

Currently collected along the

entire southwest border.

Yes

Not determined. No systematic methodology for

measuring entries and gotaways;

likely differs across sectors.

Measures event, not individuals. 

Yes, in some places. Yes

None yet 1. Limited IDENT implementation

along southwest border.

2. No usable data preceding AG

strategy, precluding a time-series

analysis of its effectiveness.

3. Not yet clear how recidivism

data will be used to model the

flow. Several possible analytic

models can be tested.

Yes, but not completely

implemented along southwest

border.

Yes

Analyses of MMP data show

a decrease in the probability

of apprehension through

1995.

Binational study data show

increasing probability of

apprehension in recent

years.

Household surveys conducted in

Mexico (e.g., the MMP) and

surveys of migrants at points of

entry and exit between the U.S.

and Mexico (e.g., the Survey of

Migration to the Northern Border)

sample different subpopulations

of migrants, who may differ in

their likelihood of apprehension. 

MMP data are only collected

annually, and retrospective

accounts of apprehensions may

be biased.

There isn’t consensus on the

methodology for estimating

probability of apprehension.

Yes Yes

(continued)

Page 81 GAO/GGD-98-21 Illegal Immigation
Appendix V 

Indicators for Measuring the Effectiveness

of the Strategy to Deter Illegal Entry Along

the Southwest Border

Indicator Source of data

Predicted outcome if AG’s

strategy is successful

Estimated number of illegal

entry attempts at U.S. ports

of entry (POE).

INS INTEX system —

random checks of

travelers at POEs.

An increase in the number of

aliens attempting to enter

illegally at POEs. 

Alien smuggling:

1. Smuggling usage.

2. Smuggling costs.

3. Tactics of smugglers.

Multiple sources:

1. INS intelligence data as

well as intelligence data

from other federal and

state agencies. 

2. MMP data .

3. COLEF data.

4. Binational study.

An increase in smuggling

fees and sophistication of

smugglers. Smugglers may

try other means of delivering

aliens to destinations (e.g.,

using vans, small trucks, and

tractor trailers).

Number of people in hotels

and shelters in Mexican

border cities.

INS intelligence

information. 

Periodic surveys by

interested organizations.

Binational study site visits.

An increase in the number of

people in hotels and shelters

in Mexican border cities.

Crime in U.S. border cities. Local crime data. Less crime in U.S. border

cities.

Page 82 GAO/GGD-98-21 Illegal Immigation
Appendix V 

Indicators for Measuring the Effectiveness

of the Strategy to Deter Illegal Entry Along

the Southwest Border

Findings Limitations

Is indicator currently being

measured?

Are there plans to measure

indicator on ongoing basis?

INTEX not yet implemented. The causes of illegal POE entries

may be difficult to disentangle.

For example, increased illegal

attempts may reflect more

effective Border Patrol strategies

between the ports, an increase in

the flow of illegal migrants, or

simply a more effective inspection

strategy at the POE.

INTEX methodology is still being

tested.

No Yes

According to INS

Intelligence, smuggling fees

are increasing.

Binational study data

suggest a rise in more

organized smuggling rings.

Changes in smuggling fees and

tactics may indicate that border

crossing is more difficult.

However it does not necessarily

indicate that migrants are less

successful at entering.

Yes Yes

Mixed.

INS reports that migrant

shelters in Mexican border

cities are filling up, and

people are staying longer.

Binational study site visits

found no “backup” in Tijuana

as result of enforcement

efforts in San Diego.

Number of people in hotels and

shelters may be affected by

economic opportunities in border

cities.

Not clear how systematically data

are collected across the

southwest border.

Yes

There was a reduction in

“nuisance” crimes by

juveniles and young adults

after implementation of

Operation Hold-the-Line in El

Paso, according to 1994

Commission on Immigration

Reform Study.

According to an INS

analysis, property and violent

crime rates dropped

between 1994 and 1995 in

San Diego.

Crime may be dropping overall,

regardless of effects of border

strategy. Need to control for such

effects using time-series analyses.

However, drops in specific types

of crime (e.g., property crime, car

thefts) may be best indicators of

drops in crimes committed by

aliens.

Not clear how systematically data

are collected across the

southwest border.

Unknown

(continued)

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Appendix V 

Indicators for Measuring the Effectiveness

of the Strategy to Deter Illegal Entry Along

the Southwest Border

Indicator Source of data

Predicted outcome if AG’s

strategy is successful

Use of public services in U.S.

border cities.

State and local sources.

Hospitals, local school

districts, local welfare

departments.

A decrease in public service

usage in border cities.

Deaths of aliens attempting

entry.

County death records.

Death records in Mexico.

University of Houston

Center for Immigration

Research reports (1996,

1997).

Depends on how

enforcement resources are

allocated. In some cases,

deaths may be reduced or

prevented (by fencing along

highways, for example). In

other cases, deaths may

increase (as enforcement in

urban areas forces aliens to

attempt mountain or desert

crossings) .

Assaults against INS agents. INS statistics. A higher incidence of

violence against INS agents

as crossing efforts of illegal

aliens are frustrated.

Abuses of aliens by INS

officers.

DOJ.

Advocacy groups.

May vary, depending on type

of enforcement effort.

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Appendix V 

Indicators for Measuring the Effectiveness

of the Strategy to Deter Illegal Entry Along

the Southwest Border

Findings Limitations

Is indicator currently being

measured?

Are there plans to measure

indicator on ongoing basis?

Commission on Immigration

Reform found some

reductions in public service

usage in the first few months

after implementation of

Operation Hold-the-Line in El

Paso.

Need to control for long-term

trends in these indicators, using

time-series analyses.

Not clear how systematically data

are collected across the

southwest border.

Unknown

Center for Immigration

Research Study (1997) found

no overall increase in the

number of deaths of illegal

aliens, but found increasing

number of deaths from

environmental exposure

(falls, hypothermia,

dehydration).

Can be difficult to identify if

deceased is an undocumented

migrant.

Problems of undercount—some

proportion of deaths in remote

areas will go undiscovered.

Data not collected on systematic

basis along southwest border.

Unknown

Assaults on Border Patrol

agents up 40% from fiscal

year 1994 to fiscal year 1996.

Numbers vary considerably

across sectors.

Violence may increase if INS is

able to frustrate drug traffickers.

But drug trafficking may be only

somewhat related to alien

smuggling. Frustrating drug

traffickers does not necessarily

imply success in deterring illegal

alien traffic.

Yes Yes

U.S. Commission on

Immigration Reform found

reductions in complaints

against Border Patrol agents

after implementation of

Operation Hold-the-Line in El

Paso (1994).

Human rights organizations

have complained about

higher abuse rates in other

sectors.

Potential for underreporting of

abuse incidents by victims.

Yes Yes

(continued)

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Appendix V 

Indicators for Measuring the Effectiveness

of the Strategy to Deter Illegal Entry Along

the Southwest Border

Indicator Source of data

Predicted outcome if AG’s

strategy is successful

B. Flow to Southwest border (deterrence)

Probability of taking a first

illegal trip to the U.S.

Probability of taking

additional illegal trips.

MMP surveys of migrant

communities in Mexico. 

Results of focus groups

conducted in Mexico

(Binational Study on

Migration).

Decreasing probability of

first-timers migrating without

documents.

Decreasing probability that

experienced migrants will

take additional trips.

Trends in applications for

temporary visas and

border-crossing cards.

INS.

U.S. Department of State.

An increase in applications

for border-crossing cards

and nonimmigrant visas.

Departures and arrivals at

airports in Mexican cities

along the Southwest border.

Where available from

Border Patrol officials in

each sector.

Roughly equal number of

departures and arrivals in

border areas where Border

Patrol has successfully

deterred entry (more arrivals

than departures in areas

where the border has not yet

been secured).

Changes in traffic through

Mexico of illegal aliens from

countries other than Mexico.

Mexican intelligence

sources.

INS

Intelligence information

Reduced traffic of aliens from

other countries through

Mexico or longer durations of

stays in Mexico by these

aliens.

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of the Strategy to Deter Illegal Entry Along

the Southwest Border

Findings Limitations

Is indicator currently being

measured?

Are there plans to measure

indicator on ongoing basis?

Some published research

shows probability of

migration is not strongly

correlated with INS

enforcement efforts. INS

enforcement may make

migrants already in the

migration stream more likely

to take trips to the U.S., to

recoup losses from earlier

apprehensions.

The probability of taking first or

additional trip is influenced by a

number of factors besides INS

efforts at the border, including

economic conditions in Mexico

and the U.S., social networks in

U.S., and availability of legal

modes of entry.

MMP Data are not representative

of the immigrant population in the

U.S. and may underrepresent

new sending areas in southern

Mexico. Retrospective survey

design. Data only collected

annually.

Yes Yes

Not determined. Application rates may simply be

indicators of greater economic

difficulties in Mexico and other

sending countries, rather than

indicators of deterrence of

migrants from attempting illegal

modes of entry.

The 1996 Act mandates that

border-crossing cards be

replaced by biometric

border-crossing cards within 3

years. This may make trends

difficult to interpret.

Yes Yes

Not determined. Data are not consistently

available.

Data do not distinguish between

trips made to Northern Mexico in

order to cross border with trips

made in order to work (in

maquiladora industries, for

example) or settle.

Not determined. Unknown

Not determined. Depends on reliability and

generalizability of intelligence

information.

Not determined. Unknown

(continued)

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Appendix V 

Indicators for Measuring the Effectiveness

of the Strategy to Deter Illegal Entry Along

the Southwest Border

Indicator Source of data

Predicted outcome if AG’s

strategy is successful

C. Number of undocumented aliens in the U.S.

Estimates of the stock of

illegal residents in the United

States.

Published analyses based

on INS and Census

Bureau data.

An eventual reduction in the

overall stock of illegal

residents in the U.S.

Number of undocumented

sojourners

Published MMP analyses. 

COLEF Survey of

Migration to the Northern

Border.

A decreased flow of illegal

sojourners to the U.S.

Estimates of overstays of

legal visas.

INS analyses;

Nonimmigrant Overstay

Method (matches record

of arrival forms with

departure forms).

By fiscal year 1999, INS is

required to have in place

a system to track all

entries and exits from the

U.S.

An increase in the number of

aliens, specifically Mexican

nationals, who try to enter

legally and overstay, in an

effort to get around border

enforcement.

Labor supply and wages in

sectors of the economy

where illegal aliens tend to

work.

National Agricultural

Workers Survey (NAWS).

A labor shortage or higher

wages in an industry that has

traditionally hired

undocumented workers.

Number of undocumented

aliens found in INS employer

inspections.

INS. A decrease in the number of

undocumented workers who

are recent arrivals to the U.S.

found in INS employer

inspections.

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of the Strategy to Deter Illegal Entry Along

the Southwest Border

Findings Limitations

Is indicator currently being

measured?

Are there plans to measure

indicator on ongoing basis?

INS estimated 5 million illegal

residents in 1996, up from

3.9 million in 1992.

Current surveys generally

measure only long-term residents

(those who have been in the U.S.

for at least 1 year).

Estimates differ based on

assumptions made about

undercount and the emigration of

illegal residents.

Difficult to determine the specific

causes of changes in the stock

(e.g., better border enforcement,

better worksite enforcement,

shrinking potential migrant

populations, etc.).

Yes, periodically. Unknown

Unclear. COLEF data

suggest that inflow and

return flow of both

documented and

undocumented migrants

might have decreased in

recent years, but analyses

do not distinguish between

the two groups.

Unrepresentativeness of samples.

Successful deterrence may have

perverse results—with aliens

spending longer time in the U.S.

on any one illegal visit. Fewer

border crossings, but an overall

increase in illegal aliens in the U.S.

Yes Yes

According to INS, about 40

percent of undocumented

immigrants in the U.S. enter

with a nonimmigrant visa.

GAO has reported on some

problems in estimating visa

overstays; estimates are likely to

be more accurate for those who

enter and leave by air.

INS has not had capability to

produce reliable estimates since

1992.

Unknown

The proportion of illegal

aliens in agriculture has

increased between 1988 and

1995.

Growing proportions in agriculture

may reflect replacement of

special agricutural workers

legalized after passage of the

Immigration Reform and Control

Act.

NAWS data are not generalizable

to sectors other than agriculture.

Yes Yes

Not determined. The number of undocumented

workers discovered is also a

function of the amount of

emphasis by INS on worksite

enforcement.

Yes Yes

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of the Strategy to Deter Illegal Entry Along

the Southwest Border

Source: GAO analysis.

Page 90 GAO/GGD-98-21 Illegal Immigation
Appendix VI 

Description of Selected Immigration

Research Projects

Several ongoing and recently completed research projects have collected

data on the flow of undocumented migrants across the border, as well as

information on migrants’ background characteristics, labor market

experience in country of origin and the United States, and potential

migrants’ intentions to take undocumented trips to the United States.

The Mexican

Migration Project

The Mexican Migration Project was funded by the National Institute of

Child Health and Human Development to create a comprehensive

binational dataset on Mexican migration to the United States. The project

is directed by Jorge Durand of the University of Guadalajara (Mexico), and

Douglas S. Massey of the University of Pennsylvania. Two to five Mexican

communities were surveyed each year during December and January of

successive years using simple random sampling methods. The sample size

was generally 200 households unless the community was under 500

residents, in which case a smaller number of households were

interviewed. If initial fieldwork indicated that U.S. migrants returned home

in large numbers during months other than December or January,

interviewers returned to the community during those months to gather a

portion of the 200 interviews.

These representative community surveys yielded information on where

migrants went in the United States, and during the months of July and

August interviewers traveled to those U.S. destinations to gather

nonrandom samples of 10 to 20 out-migrant households from each

community. The U.S.-based samples thus contain migrants who have

established their households in the United States.

The communities were chosen to provide a range of different sizes,

regions, ethnic compositions, and economic bases. The sample thus

includes isolated rural towns, large farming communities, small cities, and

very large metropolitan areas; it covers communities in the states of

Guanajuato, Michoacan, Jalisco, Nayarit, Zacatecas, Guerrero, Colima, and

San Luis Potosi; and it embraces communities that specialize in mining,

fishing, farming, and manufacturing, as well as some that feature very

diversified economies.

The study’s questionnaire followed the logic of an ethnosurvey, which

blends qualitative and quantitative data-gathering techniques. A

semi-structured instrument required that identical information be obtained

for each person, but question wording and ordering were not fixed. The

precise phrasing and timing of each query was left to the judgment of the

Page 91 GAO/GGD-98-21 Illegal Immigation
Appendix VI 

Description of Selected Immigration

Research Projects

interviewer, depending on circumstances. The design thereby combined

features of ethnography and standard survey research.

The ethnosurvey questionnaire proceeded in three phases, with the

household head serving as the principal respondent for all persons in the

sample. In the first phase, the interviewer gathered basic social and

demographic information on the head, spouse, resident and nonresident

children, and other household members, including age, birthplace, marital

status, education, and occupation. The interviewer then asked which of

those enumerated had ever been to the United States. For those

individuals with migrant experience, the interviewer recorded the total

number of U.S. trips as well as information about the first and most recent

U.S. trips, including the year, duration, destination, U.S. occupation, legal

status, and hourly wage. This exercise was then repeated for first and most

recent migrations within Mexico.

The second phase of the ethnosurvey questionnaire compiled a

year-by-year life history for all household heads, including a childbearing

history, a property history, a housing history, a business history, and a

labor history. The third and final phase of the questionnaire gathered

information about the household head’s experiences on his or her most

recent trip to the United States, including the mode of border-crossing, the

kind and number of accompanying relatives, the kind and number of

relatives already present in the United States, the number of social ties

that had been formed with U.S. citizens, English language ability, job

characteristics, and use of U.S. social services.

Data at the community and municipio (county) levels were also collected,

using several sources. First, since 1990, interviewers have used a special

community questionnaire to collect and compile data from various sources

in each community. Next, data were compiled from the Anuario

Estadistico of 1993, published in Mexico by INEGI (el Instituto Nacional

de Economia, Geografia e Informatica). Finally, data were compiled from

the published volumes of the Mexican censuses for 1930, 1940, 1950, 1960,

1970, 1980, and 1990. These decennial census data were then interpolated

for years between the censuses and extrapolated for years after 1990.

Strengths Strengths include the large number and diversity of households and

communities represented in the samples and the breadth of information

collected. The retrospective nature of the survey allows for analysis of

migration flows over a long period of time. The survey is a representative

Page 92 GAO/GGD-98-21 Illegal Immigation
Appendix VI 

Description of Selected Immigration

Research Projects

sample of communities in states in Western Mexico that have been the

traditional sending areas of Mexico; it captures both migrants that are

living in the United States as well as persons who have been in the United

States but live in Mexico.

Limitations One limitation is the representativeness of the sample. The Mexican

sample underrepresents those states in Mexico that have only recently

become sources of U.S. migration, including states in southern Mexico and

states bordering the United States. The U.S. subsample may undersample

people with little connection to their community of origin, or those who

have moved to nontraditional locations in the United States. In addition,

information on other household members collected from the head of the

household may be inaccurate, and retrospective data on migration

experience may be biased in that respondents may attribute events that

occurred to the incorrect time period or recall more recent events more

accurately than past events.

The Zapata Canyon

Project

Since September 1987, the ongoing Zapata Canyon Project has conducted

personal interviews with randomly selected undocumented immigrants

preparing to cross the border between Mexico and the United States.

Interviews are conducted 3 days per week—usually weekends—at

habitual crossing points of undocumented immigrants in the Mexican

border cities of Tijuana, Mexicali, Ciudad Juarez, Nuevo Laredo, and

Matamoros. The survey employs a short, standardized questionnaire

specifically designed not to take too much time from someone who is in

the process of entering the United States illegally. The project is directed

by Jorge Bustamante of El Colegio de la Frontera Norte (COLEF), in

collaboration with Jorge Santibanez and Rodolfo Corona.

The surveys include information on the demographic characteristics of

migrants, prior labor experience in Mexico and the United States, location

of border crossing, cost of the trip to the border, whether a smuggler was

used for crossing, how many times migrants were apprehended by the INS,

and reasons for making the trip.

Strengths The survey provides extensive time series information on illegal border

crossing and can be used for examining changes in sociodemographic

characteristics of border crossers.

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Description of Selected Immigration

Research Projects

Limitations The Zapata Canyon data may not come from a representative sample of

undocumented migrants. Thus, it is not possible to estimate the volume of

the undocumented flow from Mexico. The survey does not focus on the

extent of return migration from the United States to Mexico. A limited

number of questions can be asked of migrants who are in a hurry to make

a clandestine crossing into the United States.

Survey of Migration to

the Northern Border

This survey, also known as EMIF (Encuesta sobre Migracion en la

Frontera Norte de Mexico), was funded by the World Bank through the

Mexican Ministry of Labor and the Ministry of the Interior’s National

Council for Population. A team of researchers from El Colegio de la

Frontera Norte, directed by Jorge Bustamante, designed and administered

the survey. The survey was designed to produce direct estimates of the

volume of documented and undocumented migration flows from Mexico

to the United States as well as return migration from the United States to

Mexico.

The survey methodology derives from the theoretical concept of circular

migration and is based on an adaptation of what biological statisticians

call the “sampling of mobile populations.” The team identified the

“migratory routes” through which circular migration occurred and defined

empirical points of observation where migration could be viewed,

including bus stations, airports, railroad stations, and customs and

immigration inspection places along highways. In these places, systematic

counts of the number of migrants were made over specific periods of time.

The survey was conducted continuously from March 28, 1993, to March 27,

1994; from December 14, 1994, to December 13, 1995; and from July 14,

1996, to July 13, 1997.

The survey sampled four groups of migrants: (1) illegal migrants

voluntarily deported from the United States by the INS; (2) illegal and legal

migrants preparing to cross the border from Mexico to the United States;

(3) Mexican nationals who were permanent residents of the United States

and were returning to Mexico; and (4) permanent residents of Mexico who

have been in the United States legally or illegally and were returning to

Mexico.

The survey includes questions on the demographic characteristics of

migrants, prior labor experience in Mexico and the United States, prior

legal and illegal border crossing experience (including number of previous

crossings, whether documents were used to cross, number of times

Page 94 GAO/GGD-98-21 Illegal Immigation
Appendix VI 

Description of Selected Immigration

Research Projects

apprehended by INS, location of border crossings, whether smugglers were

used for crossing, and how much was paid to them), and reasons for

making the current trip.

Strengths The survey provides information on legal and illegal flow in both

directions—from Mexico to the United States, and from the United States

to Mexico.

Limitations The survey focuses only on labor migrants; nonlabor migrants are not

interviewed. Data collection has recently been completed; however, the

study directors have applied for additional funding to continue the survey.

The United

States-Mexico

Binational Study on

Migration

After a meeting of the Migration and Consular Affairs Group of the

Mexican-United States Binational Commission in March 1995, the

governments of Mexico and the United States decided to undertake a joint

study of migration between the two countries. The Binational Study was

funded by both the United States and Mexican governments in conjunction

with private sector funding in both countries. The main objective of the

Binational Study was to contribute to a better understanding and

appreciation of the nature, dimensions, and consequences of migration

from Mexico to the United States. National coordinators were designated

for each country, with the Commission on Immigration Reform

coordinating the work of U.S. researchers. The Binational Study was

released on September 2, 1997.

The research was conducted by a team of 20 independent researchers, 10

from each country, who reviewed existing research, generated new data

and analyses, and undertook site visits and consulted with migrants and

local residents to gain a joint understanding of the issues raised in this

study. The researchers participated in five teams studying different

aspects of migration, including (1) the size of the legal and illegal

Mexican-born population in the United States, and the size of the

migration streams crossing the border; (2) demographic, educational, and

income characteristics of Mexican-born migrants; (3) factors influencing

migration from Mexico; (4) economic and social effects of migration on

both the United States and Mexico; and (5) societal responses to migration

in both the United States and Mexico, including legislation and policy

responses, court decisions, advocacy from the private sector, and public

opinion.

Page 95 GAO/GGD-98-21 Illegal Immigation
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Description of Selected Immigration

Research Projects

Strengths The study analyzed a broad number of issues relating to illegal and legal

immigration. Its use of a combination of data from both the United States

and Mexico enhanced understanding of Mexican migration and its impacts

on both countries. The study made a number of specific recommendations

for needed research.

Limitations Data limitations often constrained the study teams’ abilities to draw firm

conclusions on many issues. Data collection and analysis has been

completed, and there are no mechanisms in place for follow-up.

Page 96 GAO/GGD-98-21 Illegal Immigation
Appendix VII 

Major Contributors to This Report

General Government

Division, Washington,

D.C.

Evi L. Rezmovic, Assistant Director, Administration of Justice Issues

Barry J. Seltser, Assistant Director, Technical/Methodological

 Assistance Group

Barbara A. Stolz, Senior Evaluator

Katherine M. Wheeler, Publishing Advisor

Office of the General

Counsel, Washington,

D.C.

Ann H. Finley, Senior Attorney

Los Angeles Field

Office

Michael P. Dino, Evaluator-In-Charge

Tom Jessor, Senior Evaluator

Nancy K. Kawahara, Senior Evaluator

James C. Geibel, Evaluator

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U.S. Department of Justice Office of the Inspector General. Immigration

and Naturalization Service Monitoring of Nonimmigrant Overstays.

Washington, D.C.: U.S. Department of Justice, September 1997.

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Years of Progress. Washington, D.C., October 1996.

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Bibliography

Page 102 GAO/GGD-98-21 Illegal Immigation
Bibliography

Page 103 GAO/GGD-98-21 Illegal Immigation
Related GAO Products

Border Patrol: Staffing and Enforcement Activities (GAO/GGD-96-65, Mar. 11,

1996).

Illegal Immigration: INS Overstay Estimation Methods Need Improvement

(GAO/PEMD-95-20, Sept. 26, 1995).

Border Control: Revised Strategy Is Showing Some Positive Results

(GAO/T-GGD-95-92, Mar. 10, 1995).

Border Control: Revised Strategy Is Showing Some Positive Results

(GAO/GGD-95-30, Dec. 29, 1994).

Border Management: Dual Management Structure at Entry Ports Should

End (GAO/T-GGD-94-34, Dec. 10, 1993).

Illegal Aliens: Despite Data Limitations, Current Methods Provide Better

Population Estimates (GAO/PEMD-93-25, Aug. 5, 1993).

Customs Service and INS: Dual Management Structure for Border

Inspections Should Be Ended (GAO/GGD-93-111, June 30, 1993).

Border Patrol: Southwest Border Enforcement Affected by Mission

Expansion and Budget (GAO/T-GGD-92-66, Aug. 5, 1992).

Border Patrol: Southwest Border Enforcement Affected by Mission

Expansion and Budget (GAO/GGD-91-72BR, Mar. 28, 1991).

(183609) Page 104 GAO/GGD-98-21 Illegal Immigation
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