United States General Accounting Office

GAO Report to Congressional Requesters

July 1998 IMMIGRATION

STATISTICS

Information Gaps,

Quality Issues Limit

Utility of Federal Data

to Policymakers

GAO/GGD-98-164

GAO United States

General Accounting Office

Washington, D.C. 20548

General Government Division

B-277490 

July 31, 1998

The Honorable Stephen Horn, Chairman

The Honorable Dennis J. Kucinich

Ranking Minority Member

Subcommittee on Government

 Management, Information, and Technology

Committee on Government Reform and Oversight

House of Representatives

The Honorable Carolyn B. Maloney

House of Representatives

Policy debates on immigration have been important in recent years and will probably continue

to be high on the national agenda for some time to come. Relevant demographic, statistical

information can inform policy decisions, but concerns continue to be expressed about an

apparent lack of such information in the area of immigration.

We are pleased to send you this report, which responds to your request that we study

policy-related needs for demographic, statistical information; report on federal statistics that

address those needs, including what is known about the quality of those statistics; identify data

gaps; and suggest strategies for improving statistics.

As agreed with your offices, unless you publicly announce the contents of this report earlier, we

plan no further distribution of it until 30 days from the date of this letter. At that time, we will

send copies to the Chairmen and Ranking Minority Members of other committees with

jurisdiction over immigration issues; the Commissioner, INS; and Director, Bureau of the

Census. We will also make copies available to others upon request.

If you or your staff have any questions about this report, please call me or Judith A. Droitcour,

Assistant Director, who served as project director for this work, at (202) 512-7997. Other major

contributors are listed in appendix V.

Susan S. Westin

Associate Director

Advanced Studies and Evaluation

 Methodology Group
Executive Summary

Purpose Immigration issues are high on the national policy agenda. But there have

been repeated indications that statistics that could inform key debates are

lacking, misleading, or otherwise inadequate. In response to a request

from the House Government Reform and Oversight Subcommittee on

Government Management, Information, and Technology, this report

(1) identifies policy-related information needs for immigration statistics;

(2) identifies federal statistics (and information gaps) on the full range of

demographic concepts relevant to immigration policy decisions and

determines what is known about the quality of these statistics; and

(3) identifies strategies for improving immigration statistics.

Background Published immigration statistics include information on several

demographic concepts, such as immigration flow (i.e., the number of

persons who come to reside in the United States each year or the number

who transition from one legal status to another). Other immigration

statistics indicate the size of the resident foreign-born population, net

change in size, and emigration (i.e., the estimated number of foreign-born

residents who leave the United States to live in another country). Statistics

on the legal status of foreign-born residents have also been published.

Most federal statistical information on the foreign-born is provided by two

agencies: the Immigration and Naturalization Service (INS) and the Bureau

of the Census. INS provides information relevant to flow. INS and the

Census Bureau each provide some information on the size of the resident

foreign-born population and on annual change in size. The Census Bureau

provides an estimate of emigration.

Results in Brief Congress periodically makes decisions about numerous immigration

policies, such as whether to decrease numerical limits for legal immigrants

or increase them for temporary workers. Thus, informed decision-making,

by congressional committees and Members of Congress as well as

interested members of the general public, requires information on

immigration flow, by legal status. Congress also decides on the eligibility

of the foreign-born for government benefits and services—with different

benefits typically allowed or restricted for different categories of the

foreign-born population, such as legal permanent residents (LPRs) or illegal

immigrants. GAO identified 33 discrete categories of demographic

information that could be relevant to congressional decision-making.

Page 2 GAO/GGD-98-164 Quality of Immigration Statistics
Executive Summary

Information on immigration flow is reported in annual INS Statistical

Yearbooks. Statistics on demographic categories other than flow are

reported in a more scattered fashion; indeed, a variety of INS and Bureau of

the Census publications, including the INS Web page, must be accessed in

order to retrieve basic information.

INS records that are maintained for administrative purposes are the basis

for most federal statistics on flow. These statistics describe the number of

new legal permanent residents (persons with new green-card status), new

refugees and asylees, and new naturalized citizens. As reported in the INS

Yearbook, however, these statistics are limited by conceptual problems

and confused reporting, undercounts, and information gaps. For example,

data on annual trends in the number of new green cards authorized,

although highlighted in the INS Yearbook, are significantly affected by INS’

administrative problems in processing green-card applicants and thus may

not accurately reflect flow over time. The number of new asylees—

persons granted asylum—and the number of persons granted citizenship

are undercounted in the Yearbook tallies because the data omit certain

groups of persons, such as those granted asylum on appeal or minor

children of new citizens. Statistics for other demographic categories, such

as the total number of foreign-born persons who take up residence in the

United States each year, are not available.

While the Bureau of the Census provides some information on the size of

the resident foreign-born population, annual net change in size, and

emigration, Census has not quantitatively evaluated these data with

respect to coverage, accuracy of reported place of birth, or nonresponse

rates. Moreover, there are no separate Census data on legal status because

none of the surveys ask questions about legal status. Such questions are

very sensitive, and negative reactions to them could affect the accuracy of

responses to other questions on the survey.

INS has made efforts to fill information gaps for some legal statuses by

using the limited data that are available and creating assumption-based

models. The resulting estimates are necessarily uncertain because

assumptions and judgments are substituted for data.

Because of the above problems, GAO attempted to identify existing

strategies or develop new ones to improve immigration statistics. In

particular, GAO devised a new method for collecting survey data on the

legal status of foreign-born respondents. The “three-card method” asks

questions that are less sensitive than a direct question about legal status,

Page 3 GAO/GGD-98-164 Quality of Immigration Statistics
Executive Summary

and it ensures privacy of response. Yet this method allows statistically

unbiased survey estimates for all major legal statuses. GAO conducted a

preliminary qualitative test of the new method and concluded that this

method appears to show promise and to deserve further testing and

development. GAO also identified strategies for evaluating survey data on

the foreign-born.

Principal Findings

Policy-Related Information

Needs Include Data on

Flow and Other Major

Demographic Concepts

Informed decision-making on immigration issues requires data on

• immigration flow, including separate information on flow into the United

States and transitions to new legal statuses,

• size of the foreign-born population,

• net change in size, and

• emigration.

Because almost all immigration laws involve specific legal statuses, it is

crucial that information on each major demographic concept be reported

separately for each of the major legal statuses (legal permanent residents,

refugees and asylees, persons here with a temporary visa, illegal

immigrants, and naturalized citizens). All together, there are 33 relevant

demographic categories. GAO summarized these categories and their

interrelationships in an information typology that helps clarify (1) the

differences between demographic concepts and (2) which statistics

can—and which cannot—be validly compared.

Most of the information specified in GAO’s typology is required, either

generally or specifically, by existing laws or has been requested by

congressional committees. Virtually all of it is directly or indirectly

relevant to recurrent congressional activities, such as revising numerical

limits for visas issued to immigrants or temporary workers.

INS Statistics on

Immigration Flow Are

Limited

The INS Yearbooks present a variety of data on immigration flow, including

counts of new LPRs, new refugees and asylees, and new U.S. citizens—all

based on administrative records. But as presented, these data do not

convey a clear and valid picture of immigration flow that is relevant to

policy information needs. Rather, there are instances of conceptual

Page 4 GAO/GGD-98-164 Quality of Immigration Statistics
Executive Summary

problems and confused reporting, as well as undercounts and information

gaps.

Conceptual problems and confused reporting are evident in the

introductions to the INS 1995 and 1996 Yearbooks, which alternatively

highlight a “decrease” (1995) and a “rise” (1996) in immigration to the

United States. These annual trends mix data on two types of flow: (1) flow

of new LPRs into the United States and (2) transitions by persons already

living here into LPR status. These trends in “combined-flow” can reflect

• a change in the number of persons coming into the United States,

• an administrative logjam (slowdown) or speed-up in INS’ issuing of green

cards to foreign-born persons already living here, or

• some combination of the two.

Mixing two different forms of flow is not a trivial problem because,

according to the Yearbook, the majority of new green-card holders were

already residing here—often either illegally or on temporary visas—and

because, in recent years, INS has experienced problems in processing green

cards. (The agency is struggling to catch up with backed-up applications,

which numbered approximately 775,000 as of April 1998.) Thus, the trends

that INS highlights are very difficult to interpret, but readers of the

Yearbook introduction are not alerted to this—unless they turn to the

body of the report.

Another instance of a conceptual problem exacerbated by confused

reporting occurs when the INS Yearbook presents information relevant to

flow for legal immigration (i.e., the number of new green cards authorized

in the past year), but not for illegal immigration. Instead, the Yearbook

presents information on net change in the size of the illegal population.

For a valid comparison of data on legal flow to data on illegals,

comparable categories must be used; that is, legal flow should be

compared to illegal flow—not to net change in the size of the illegal

population. Because the INS Yearbook does not point out the difference

between flow and net change, there is a potential for a reader to make an

invalid comparison. Net change in the illegal population is likely to be

considerably smaller than illegal flow because the net change statistic

subtracts out deaths, emigration, and legalizations for all illegal

immigrants, regardless of how many years they have resided here. A likely

consequence is that—for readers of the INS Yearbook—the flow of illegal

immigrants is understated relative to the flow of legal immigrants.

Page 5 GAO/GGD-98-164 Quality of Immigration Statistics
Executive Summary

The 1996 INS Yearbook also presents figures that undercount two other

categories of flow:

• Persons granted asylum are undercounted by about a third or more, based

on information that GAO obtained from computer systems maintained by

INS, the Department of State, and the Department of Justice’s Executive

Office of Immigration Review (EOIR). Groups omitted from the Yearbook

tally include (1) persons who were granted asylum on appeal and

(2) trailing relatives of persons granted asylum. (These trailing relatives

who “followed to join” a principal asylee were not included in that asylee’s

original application—often because they were not in the United States at

the time.)

• The number of new naturalizations is undercounted by an unknown

amount. INS administrative records on naturalizations do not include most

minor children who naturalize along with their parents.

There are also information gaps for certain categories of flow. For

example, no statistic is reported for the number of new residents who

entered the United States with temporary (e.g., student, worker) visas.

This number cannot be tallied accurately because INS record-keeping

systems are not designed to identify reentries. Thus, a foreign student

residing here for 4 years who visits his home country twice a year would

be tallied as eight separate 6-month visits by up to eight persons, rather

than as a single individual’s 4-year stay.

Federal Statistics on Other

Demographic Concepts

Are Marked by Gaps and

Uncertain Estimates

Information on the size of the foreign-born population, change in size, and

emigration is limited by important data gaps. The data that do exist have

not been evaluated, despite important questions about their quality.

The Census Bureau provides census and survey data on size and net

change in size for the total foreign-born population and for naturalized

citizens. The Bureau also estimates emigration by comparing 1980 and

1990 census data. Analysts have raised a variety of questions about

possible problems with data on the foreign-born, such as undercoverage

(because, e.g., illegal immigrants may deliberately avoid enumeration). Yet

Census has not conducted a quantitative evaluation of its census or survey

data on the foreign-born.

The Census Bureau’s estimate of emigration represents one instance

where census undercoverage of the foreign-born clearly limits the utility of

the data. The uncertainty of the emigration estimate is important because

Page 6 GAO/GGD-98-164 Quality of Immigration Statistics
Executive Summary

information on emigration is needed to balance information on flow—and

also because estimates of emigration figure importantly in INS’ indirect

estimates of population size for illegals and legal permanent residents.

There are no direct data on emigration. The Census Bureau attempts to fill

this gap through a method of examining change in the size of various

arrival groups across two points in time. For example, the 1970-79 arrival

group (i.e., foreign-born residents who arrived here between 1970 and

1979) was counted in the 1980 and again in the 1990 decennial census.

Emigration for that group is estimated according to the amount it

dwindled between 1980 and 1990. But the data for certain pre-1980 arrival

groups (e.g., Mexican and Salvadoran arrival groups) showed growth

between 1980 and 1990 rather than dwindling—a logical impossibility

since all had arrived before 1980. This pattern of apparent growth, which

could be explained by differential census coverage (i.e., lower coverage of

Mexican and Salvadoran residents in 1980 than in 1990), raises questions

about the census counts that underlie the emigration calculation.

Data gaps occur for the number of residents in specific legal

statuses—from LPRs to illegal immigrants—and for net change in the sizes

of these resident population groups. Direct questions on legal status are

very sensitive and, according to the Census Bureau, have not been asked

in the census or in any survey that it has conducted. The gaps for the

population sizes of various legal statuses cannot be easily filled by using

INS records, as these are limited to flow. To fill data gaps for the population

sizes of certain legal statuses, INS has developed indirect estimates of the

number of illegal immigrants and legal permanent residents. These

estimates address key gaps and thus would seem to represent a step

forward in providing information, but multiple sources of uncertainty

remain—owing to the lack of direct empirical data and the need for major

assumptions that, in some cases, are not fully supported.

Strategies for Improvement INS is working toward correcting some of the problems in flow statistics

discussed above. For example, a system that tracks foreign students over

time (and avoids duplicate counts when reentries occur) is being

pilot-tested at INS. This system is based on assigning each foreign student a

unique high-tech identification card, which he or she must use for all

entries to and exits from the United States. INS is also working on an

indirect estimate of illegal flow. (INS has worked with Census to obtain

some of the necessary data for this estimate.) But INS’ current efforts do

not address all the problems identified above; for example, the Yearbook

Page 7 GAO/GGD-98-164 Quality of Immigration Statistics
Executive Summary

tally of persons granted asylum does not include trailing relatives of

principal asylees.

Various strategies for evaluating the quality of census and survey data on

the foreign-born would involve joint work on the part of INS and the

Bureau of the Census. For example, coverage problems might be assessed

by matching INS administrative data and census records.

In addition, testing and developing the “three-card method”—which GAO

devised for asking less sensitive questions about legal status in

surveys—might help fill important data gaps in the future. That is, if

successfully developed and implemented, the three-card method would

provide survey data on the number of legal permanent residents residing

in the United States, the number of refugees and asylees (without green

cards) residing here, and so on; an indirect estimate of the number of

persons residing here illegally could also be obtained. By using the method

in a series of surveys, net change could also be tracked. GAO’s preliminary

test indicated that the less sensitive questions on legal status were

acceptable to the interviewers and foreign-born Hispanic farmworkers

who participated.

Recommendations GAO recommends that

• to help correct undercounts, reduce conceptual problems, and where

possible, fill gaps for information on immigration flow, the Commissioner

of INS should (1) evaluate and, where feasible, work toward improving data

on flow and (2) utilize a set of demographic categories (or an information

typology) that clearly distinguishes different concepts and helps determine

which statistics can fairly be compared to others;

• to eliminate confused reporting of data and estimates concerning

immigration flow, the Commissioner of INS should more clearly report

information about trends in legal immigration flow and about the

difference between the concepts of flow and net change in the INS

Yearbook—or develop a new reporting format that communicates more

effectively to policymakers and interested members of the general public;

and

• to reduce the uncertainty associated with statistical estimates of

demographic concepts other than immigration flow, fill information gaps

for specific legal statuses, and address fragmented reporting, the

Commissioner of INS and the Director of the Bureau of the Census should

together (1) devise a plan of joint research for evaluating the quality of

Page 8 GAO/GGD-98-164 Quality of Immigration Statistics
Executive Summary

census and survey data on the foreign-born; (2) further develop, test, and

evaluate the three-card method that GAO devised for surveying the

foreign-born about their legal status; and (3) either publish a joint report

or coordinate reports that present information on population size, net

change, and emigration.

Agency Comments GAO met with INS officials who had reviewed a draft of this report,

including the Director of the Statistics Branch. INS indicated that it is

currently working to improve the clarity of statistical reporting in the

Yearbook and that it finds GAO’s typology very useful.

With respect to GAO’s recommendation concerning the three-card method,

INS made two comments:

• First, INS suggested that because it is not an expert in survey methodology,

its appropriate role would be limited to providing support and

consultation to Census in that agency’s efforts to develop, evaluate, and

test the new method. GAO believes that, as stated above, the

recommendation for joint INS-Census work allows latitude for INS and

Census to determine their appropriate roles.

• Second, INS indicated that it would need an independent evaluation of the

three-card method before committing funds to the method’s development.

GAO agrees that INS’ obtaining an independent evaluation of the method

before proceeding with further development would be prudent.

The Bureau of the Census provided written comments (see app. IV), which

raised no objections to GAO’s findings on data gaps and the quality of

federal statistics on immigration.

The Census Bureau stated a concern about its involvement in a survey

designed to obtain information on the legal status of the foreign-born.

GAO’s recommendation is only that the Census Bureau be involved in the

development, testing, and evaluation of the new method, not necessarily in

any resulting survey. GAO believes that Census would bring essential

expertise to designing and overseeing this work. Testing—even large-scale

testing—need not involve data collection by the Census Bureau.

The Department of State and the Department of Labor provided technical

comments, which were incorporated as appropriate. The Department of

Health and Human Services had no comments on the report.

Page 9 GAO/GGD-98-164 Quality of Immigration Statistics
Contents

Executive Summary 2

Chapter 1 

Introduction

12

Background 12

Objectives, Scope, and Methodology 15

Organization of This Report 18

Chapter 2 

Policy-Related

Information Needs

19

An Information Typology 19

A Consideration of Policy-Related Information Needs 22

Chapter 3 

Immigration Flow

25

Conceptual Problems and Confused Reporting 27

Undercounts 32

Data Gaps 34

Chapter 4 

The Resident

Foreign-Born

Population: Size, Net

Change, and

Emigration

36

The Available Data 38

Gaps and Uncertain Estimates 39

Existing Census and Survey Data: Lack of Evaluation 41

Reporting Data on Size of the Foreign-Born Population, Change

in Size, and Emigration

46

Chapter 5 

Improving

Information: Current

Initiatives and New

Strategies

47

Current Initiatives for Improving Information 47

Strategies for Improving Census and Survey Data on the

Foreign-Born

48

Conclusions 58

Recommendations 60

Agency Comments 61

Appendixes Appendix I: Experts on Immigration Whom We Consulted 64

Appendix II: Demographic Characteristics 65

Appendix III: The Three-Card Method 69

Appendix IV: Comments From the Bureau of the Census 78

Appendix V: Major Contributors to This Report 80

Page 10 GAO/GGD-98-164 Quality of Immigration Statistics
Contents

Bibliography 81

Tables Table 2.1: Typology of Statistical Information on Foreign-Born

Residents

20

Table 3.1: Published Federal Statistics on Immigration Flow, With

Descriptive Quality Rating and Reason

26

Table 3.2: Persons Granted Asylum and Whether Included in

Yearbook Count

33

Table 4.1: Published Federal Statistics for Three Demographic

Concepts, Descriptive Quality Rating and Reason, 1996

37

Table 4.2: Reasons for Underrepresentation of Foreign-Born in a

Census or Survey and Type of Evidence

42

Figures Figure 3.1: Net Change in the Size of the Illegal Population 31

Figure 5.1: Card 1 of the Three-Card Method 50

Figure 5.2: Card 2 of the Three-Card Method 52

Figure 5.3: Card 3 of the Three-Card Method 54

Figure III.1: Statistical Expression of the Three-Card Estimator,

Its Variance, and Technique Effect

75

Abbreviations

CLAIMS Computer Linked Application Information Management

System

CPS Current Population Survey

DOL Department of Labor

EOIR Executive Office of Immigration Review

EWI Entry without inspection

GPO Government Printing Office

INA Immigration and Nationality Act

INS Immigration and Naturalization Service

IRCA Immigration Reform and Control Act

LPR Legal permanent resident

NAWS National Agricultural Workers Survey

NCES National Center for Education Statistics

PES Post Enumeration Survey

RAPS Refugee, Asylum, and Parolee System

Page 11 GAO/GGD-98-164 Quality of Immigration Statistics
Chapter 1 

Introduction

Background “Reliable data is a necessary ingredient for credible policy and its

implementation.” So stated the U.S. Commission on Immigration Reform

in 1994 (p. xxxi). But the Commission found that throughout its own

inquiry, inadequate data made it difficult to assess the impact of

immigration policy and of immigration itself on American society.

Dissatisfaction with information on immigration has also surfaced on

Capitol Hill. In spring 1996, the Immigration and Naturalization Service

(INS) issued a press release with the headline: “U.S. Legal Immigration

Down 10.4 Percent in 1995.” The headline is based on a 1994-95 reduction

in the number of green cards authorized, and the reduction appears to

have been caused mainly by a logjam in INS’ processing of green-card

applications.1

 Subsequently, INS and most of the experts testifying at a

congressional hearing reported that, in general terms, legal immigration

was increasing.2

 At that hearing, it also became apparent that some

policymakers and reporters had been confused about whether

immigration was increasing or decreasing.

Recent dissatisfaction with immigration statistics comes roughly a decade

after a thorough review of immigration statistics (Levine et al.,

1985) summed up the situation as a history of neglect and despite some

efforts to provide better information.3

 It has been a decade during which

levels of legal immigration increased while patterns of immigration shifted

further away from the European dominance of the early and mid-20th

century to heavier flows of Asian and Latin American immigrants. At the

same time, illegal immigration emerged as a major concern, and the INS

budget increased dramatically, mainly because of more intensive efforts to

curtail illegal immigration. (During the 1990s, INS’ budget quadrupled; it is

expected to reach $4 billion in fiscal year 1999—up from less than

$1 billion in 1992.)

In recent years, the public—particularly California voters—entered the

debate about the value and cost of immigration.4

 And a series of major

1

Identity cards attesting the legal permanent resident (LPR) status of an alien in the United States are

termed green cards because of their former color.

2

Hearing before the House Subcommittee on Immigration and Claims, Committee on the Judiciary,

May 16, 1996.

3

For a follow-up on implementation of recommendations from two National Academy of Sciences

reports on immigration statistics (Levine et al., 1985; Edmonston, 1996), see GAO/GGD-98-119.

4

In California, where immigration increases have been concentrated, Proposition 187 was passed in

1994 calling for public agencies, such as schools, to report suspected illegal immigrants to INS—a

measure that was blocked in court.

Page 12 GAO/GGD-98-164 Quality of Immigration Statistics
Chapter 1 

Introduction

bills—affecting legal immigration, the transition from illegal to legal status,

and the public benefits for which immigrants in various statuses are

eligible—were introduced and debated in Congress.

Debates concerning immigration continue. For example, this year

Californians passed a hotly contested proposition to end bilingual

education. Also, the computer industry asked Congress to increase the

number of temporary visas for high-tech workers. Thus, there is an

increased need for valid, reliable, and clear policy-relevant information.

Congressman Ed Bryant of Tennessee called for INS to answer direct

questions, such as: “How many people—in total, including every category

. . . enter the United States each year?”5

 The Commission on Immigration

Reform (1994) also issued a call for new methods to be developed to meet

some of the difficult challenges in immigration statistics, such as

estimating the flow of illegal immigrants into the United States.

Definition of Foreign-Born

U.S. Residents

The resident foreign-born population is defined here as all persons who

were born abroad (to parents who were not U.S. citizens) and who now

either (1) are in a permanent legal status (naturalized citizen, legal

permanent resident, refugee, person granted asylum) or (2) if in a

temporary legal status or here illegally, remain in this country for over a

year. The requirement for remaining more than a year is based on the U.N.

definition.

Demographic Concepts Four basic demographic concepts (categories of statistics) are crucial to

understanding information on the foreign-born population:

• The inflow—or in this report, flow—refers to the movement of

foreign-born persons into the United States and, as explained below, their

transition into specific legal statuses.

• The size of the foreign-born population in the United States (sometimes

referred to as “stock”) is the total number of foreign-born persons residing

here at any given time, including those who have naturalized.

• Net change in the size of the foreign-born population over a specific

period of time can be calculated using a demographic balancing equation,

accounting for flow, deaths, and emigration (see Bogue et al., 1993; Pollard

et al., 1981). The foreign-born population increases when the flow of new

residents into the country exceeds the number who emigrate or die.

5

Hearing before the House Judiciary Subcommittee on Immigration and Claims, May 16, 1996.

Page 13 GAO/GGD-98-164 Quality of Immigration Statistics
Chapter 1 

Introduction

• Emigration refers to persons moving out of the United States to take up

residence in a foreign country. In this report, we are concerned with the

emigration of only foreign-born persons—not the emigration of persons

born in the United States.

Legal Statuses The foreign-born population may be subdivided into groups, such as those

defined by the various legal immigration statuses: legal permanent

residents, refugees and asylees, those legally permitted to reside here on a

temporary basis, illegal immigrants, and naturalized citizens.

Virtually all laws and policies on immigration differentiate foreign-born

persons according to their legal status.6

 Thus, from a policy perspective,

legal status is critical information. Consistent with this view, in 1994, the

U.S. Commission on Immigration Reform, commenting on the need to

improve estimates of the costs and benefits of legal and illegal

immigration, stated that confusion results from grouping together illegal

immigrants, legal immigrants, and refugees.

Two Types of Flow In considering the process of immigration flow, we recognized that

transitions from one immigration status to another must be considered.

Persons who enter the United States in one immigration status often

adjust or change to a different status, and statistics have been reported on

this process.7

 Such transitions are a form of “flow” (i.e., flow to a

particular status). This means that flow can indicate not only new entries

into the United States, but also transitions or adjustments to a different

legal category or status. We believe that it is important to recognize—and

to clearly distinguish between—these two, very different types of flow.

Federal Agencies Providing

Statistics on Immigration

Most of the available federal statistical information on the foreign-born is

provided by two agencies: the Immigration and Naturalization Service and

the Bureau of the Census. INS provides information relevant to flow. INS

and Census each provide some information on the size of the resident

foreign-born population and net change. Census also provides an estimate

of emigration (i.e., the estimated number of foreign-born residents who

6

For example, the Immigration and Nationality Act (INA) of 1952, as amended (8 U.S.C. 1101 et seq.)

defines various classes of foreign-born persons (legal statuses) and indicates rights and limitations of

privileges for persons in those classes.

7

For example, statistics are currently reported on the aliens who adjust to LPR (or green-card)

status—and on LPRs who transition to naturalized citizenship.

Page 14 GAO/GGD-98-164 Quality of Immigration Statistics
Chapter 1 

Introduction

leave the United States to live in another country). Some additional

information is maintained by the Departments of State, Health and Human

Services, and Labor.

Objectives, Scope,

and Methodology

Objectives The objectives of this report are (1) to identify policy-related information

needs for immigration flow and other key demographic concepts that are

relevant to migration; (2) to identify federal statistics on the flow of

immigrants (and information gaps) and to determine what is known about

the quality of existing statistics on flow; (3) to identify federal statistics

relevant to other key demographic categories and to determine what is

known about their quality; and (4) to identify strategies for improving

immigration statistics.

Scope The scope of this report is limited to current federal statistics that provide

basic demographic, statistical information on the resident foreign-born

population.8

 Current federal statistics are defined here as those published

by a federal agency for fiscal or calendar year 1996—the most recent year

for which statistics were generally available during the time we collected

data from federal agencies (from Nov. 1997 to Apr. 1998).9

 With respect to

policy-related information needs, our focus is on congressional

information needs—that is, the statistical data that can inform

congressional debates on immigration issues.

In assessing the quality of federal statistics on the foreign-born, we limited

our work to determining what is known about their quality, including what

can be determined from logical comparisons and analysis. In exploring

new strategies, we initially limited our scope to the development of ideas;

in one instance, we were subsequently able to conduct a preliminary,

8

This report does not address needs for special information, e.g., information on criminal aliens (see

GAO/T-GGD-97-154).

9

Published federal statistics refer to numbers included in an agency publication or release (e.g., a press

release), an agency “working paper” that has been distributed externally, or a specific listing on an

agency Internet Web page. (In some instances, published federal statistics based on sample surveys

were presented without confidence intervals. In those instances, we requested confidence intervals

from the agency and presented that information together with the published federal statistic.)

Page 15 GAO/GGD-98-164 Quality of Immigration Statistics
Chapter 1 

Introduction

qualitative test of a new method for estimating legal status in a census or

survey.

Methodology

Identifying Policy-Related

Information Needs

To identify policy-related information needs, we reviewed recent

congressional debates, bills, and laws concerning immigration to

determine the kinds of basic demographic, statistical information on the

foreign-born needed by congressional policymakers. We also reviewed

basic texts on demography, which identify key concepts, and consulted

with immigration experts. (App. I lists the immigration experts we

consulted.)

In reviewing federal agency literature, material from relevant hearings, and

laws requiring information on the foreign-born, we found that such

information has not been gathered or reported according to a common

framework or typology. As noted earlier, there have been instances of

confusion in interpreting these kinds of information. Therefore, to identify

policy-related information needs concerning the legally and illegally

resident foreign-born population, we proceeded through a two-step

process, which included

• developing a basic typology or set of demographic categories (i.e., a

systematic framework defining various types of policy-relevant

demographic, statistical information on the foreign-born population and

their interrelationships) and

• examining, in a general sense, whether these types of information were, in

fact, needed by Congress and interested members of the general public.

We developed our information typology (set of demographic categories) in

consultation with immigration experts. We then examined the need for

these types of information by reviewing laws requiring demographic,

statistical information on the foreign-born, past congressional requests for

information, and recurrent congressional activities. We discussed our

typology with staff at the Immigration and Naturalization Service.

Identifying and Assessing

Current Federal Statistics

Using our typology, we identified relevant federal statistics and gaps.

Briefly, we reviewed literature published by federal agencies and followed

up with officials and staff at INS, the Bureau of the Census, and other

agencies.

Page 16 GAO/GGD-98-164 Quality of Immigration Statistics
Chapter 1 

Introduction

We then evaluated the quality of the relevant statistics, considering

technical adequacy and timeliness as well as the adequacy with which the

information was reported. To guide our work, we developed checklists for

statistical quality, based on a review of literature (including federal agency

standards, published empirical assessments of statistical quality, and

evaluation and statistical texts) and discussions with agency staff. We

used these checklists to ensure comprehensiveness in interviewing federal

agency staff, experts, and users about statistical quality and in reviewing

relevant literature. We then developed quality ratings to describe

published statistics in each demographic category as problem-free or as

limited by conceptual problems and confused reporting, as overcounts or

undercounts, or as uncertain or unevaluated statistics. If no published

federal statistic could be identified for a demographic category, the

descriptive rating consists of the notation that a gap exists.

Identifying Strategies for

Improvement

To identify strategies to improve federal statistics on immigration, we

(1) logically analyzed the problems we had identified, (2) talked with

agency staff and experts about possible approaches, (3) reviewed

literature, and (4) developed our own new strategy for collecting relevant

data. In particular, based on previous research on survey methods for

asking sensitive questions and on demographic methods for estimating

illegal immigrants, we devised a new method for interviewing foreign-born

respondents and collecting data on their immigration status while

protecting privacy—the three-card method. We pretested the three-card

method in interviews with foreign-born Hispanics in farmwork settings, at

a legal clinic for immigration problems, and at a city “drop-in” center.

(These interviews were conducted by members of our staff who are fluent

in Spanish.) We then conducted a preliminary test of the acceptability of

this method to interviewers and respondents by contracting for 81

interviews with foreign-born farmworkers as a supplement to the National

Agricultural Workers Survey (NAWS), debriefing the interviewers who

administered the questionnaire, and examining the results for signs of

respondent comfort with the series of questions.

We conducted our audit work in accordance with generally accepted

government auditing standards between June 1997 and June 1998.

Preliminary work on the three-card method was conducted earlier. We did

not conduct an audit of how the INS and Census data were initially

gathered and processed by the agencies.

We requested comments on a draft of this report from INS, Census, and the

Departments of State, Labor, and Health and Human Services. On July 13,

Page 17 GAO/GGD-98-164 Quality of Immigration Statistics
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Introduction

1998, Census provided written comments, and on July 15, INS provided oral

comments at a meeting attended by INS officials including the Director of

the Statistics Branch. INS’ and Census’ comments are discussed in relevant

sections of chapter 5 and appendix III. INS, as well as State and Labor,

provided some technical comments and suggestions for clarification,

which we incorporated as appropriate. Health and Human Services

reviewed a draft and said that it had no comments.

Organization of This

Report

Chapter 2 of this report presents our typology of policy-relevant statistical

information on the foreign-born population (i.e., the set of demographic

categories) and links this typology to policy-related information needs.

Chapter 3 identifies and assesses current federal statistical information on

immigration flow. Chapter 4 identifies and assesses corresponding

information on other key demographic concepts—size of the foreign-born

population, emigration, and change in the size of the foreign-born

population. Chapter 5 discusses strategies for improvement and makes

recommendations to the Commissioner of INS and the Director of the

Bureau of the Census.

Appendixes provide more detailed information of concern to technical

readers. Appendix I lists the immigration experts we consulted. Appendix

II briefly reviews available information on the demographic characteristics

of foreign-born residents. Appendix III provides information on the

three-card method for collecting survey data on legal status and our

preliminary test of its acceptability to both respondents and interviewers.

Appendix IV reprints the comments from the Bureau of the Census.

Page 18 GAO/GGD-98-164 Quality of Immigration Statistics
Chapter 2 

Policy-Related Information Needs

A basic typology of policy-relevant statistical information on the resident

foreign-born population1

 can be defined by combining two dimensions:

one consisting of four demographic concepts that are relevant to

migration (flow, size of the foreign-born population, net change in size,

and emigration) and the other consisting of legal statuses (legal permanent

residents, refugees and asylees, persons permitted to reside here on a

temporary basis, illegal immigrants, and naturalized citizens). We

developed the typology (or set of demographic categories) as a tool for

sorting and defining different types of statistical information on the

foreign-born population.

Reviewing specific policy-relevant information needs with reference to our

typology, we found that

• Congress has passed laws requiring, either generally or specifically, much

of the information included in the typology and, in some instances, has

indicated that the information is needed to improve decision-making;

• Congressional committees have requested some of the information; and

• Virtually all of the information is directly or indirectly relevant to various

congressional activities (e.g., information on immigration flow is relevant

to establishing or changing numerical limits for certain classes of

immigrants and temporary visas).

An Information

Typology

To build a policy-relevant framework for types of demographic, statistical

information on the foreign-born, we crossed the two

dimensions—demographic concept and legal status of the foreign-born, as

shown in table 2.1. In doing so, we defined flow with three columns to

distinguish new arrivals, transitions to a new status, and total flow to

specific legal statuses (e.g., all new LPRs). We defined each of the other

demographic concepts—the size of the foreign-born population, net

change in size, and emigration—with an individual column. The rows of

the table represent major legal statuses. In total, we identified 33 discrete

categories, each of which specifies a distinct type of information.

1

In this report, the term foreign-born resident is used to refer to all foreign-born who are in a

permanent legal status or who, if in a temporary legal status or here illegally, have remained here for

longer than a year.

Page 19 GAO/GGD-98-164 Quality of Immigration Statistics
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Policy-Related Information Needs

Table 2.1: Typology of Statistical Information on Foreign-Born Residentsa

Annual flow

Legal status of foreign-born

New residents (entered U.S. during

reference year)

Transitions to a new status (during

reference year)

A. Legal permanent residents Number who received green-card

status upon admission to the U.S.

Number transitioning to green-card

status; entered the U.S. earlier

(as B, C, D)

B. Refugees and asylees (without LPR status)b Number who were admitted to the

U.S. as refugees or as asylees

(“trailing relatives” of those granted

asylum)

Number of new asylees who had

entered the U.S. earlier

(as C, D)

C. Students, temporary workers, and their

families; others temporarily here who

stayed > 1 yearc

Number of new residents who

entered with student or work visa, or

other temporary form of admission

Number already here who newly

obtained legal temporary status;

entered U.S. earlier

(as D)

D. Illegal immigrants (EWIs and overstays)

who stayed > 1 year

Number of new illegal immigrants

who “entered without inspection”

(EWI)

Number who illegally overstayed;

entered U.S. earlier (as C)

E. Naturalized citizens Not an entry statusd Number who achieved citizenship;

entered U.S. earlier (as A-D)

Total Total annual flow from foreign

countries to U.S. = sum of above

Total not meaningful because of

double-counting; some persons

make more than one transition per

year

Page 20 GAO/GGD-98-164 Quality of Immigration Statistics
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Policy-Related Information Needs

Population size Net change in size

Annual emigration

Demographic concept

Combined-flow to each status

(sum of first two columns)

Number of foreign-born

persons residing here (at

given point in time)

Annual increase or decrease

in the size of foreign-born

population

Foreign-born emigrating

(during reference year)

All new LPRs Number of LPRs Increase or decrease in the

number of LPRs residing here

Number of LPRs who

emigrated

All new refugees and asylees Number of refugees and asylees

(without LPR status)

Increase or decrease in the

number of refugees and asylees

(without LPR status) residing

here

Number of refugees and

asylees (without LPR status)

who emigrated

All residents who newly achieved

temporary legal status

Number of residents with

student or temporary work visas

or other temporary legal status

Increase or decrease in the

number of residents with

temporary legal status

Number of residents with legal

temporary status who

emigrated

All new illegal immigrants Number of residents here

illegally

Increase or decrease in number

of illegal residents

Number of illegal residents

who emigrated

Same as number in previous

column

Number of naturalized citizens Increase or decrease in the

number of naturalized citizens

residing here

Number of naturalized citizens

who emigrated

Total not meaningful because of

double-counting; some enter the

U.S. and transition to a different

status within the same year

Total foreign-born who reside

here = sum of above

Net change in the size of the

foreign-born population = sum

of above

Total foreign-born who

emigrated = sum of above

Legend

EWI Entry without inspection

LPR Legal permanent resident

Note: Statistics are not relevant to the shaded categories.

aCurrent data or estimates and trends.

bThe term “asylees” refers to persons granted asylum.

cOther foreign-born residents who were admitted temporarily include (1) trainees, treaty-traders,

and investors as well as their families; (2) special groups, such as those given temporary

protected status or extended voluntary departure; (3) parolees, that is, persons allowed to enter

the United States on a nonpermanent basis for urgent humanitarian reasons or when significant

public benefit is likely; and (4) persons entering on tourist or other short-term visas who

nonetheless remain in the United States longer than a year.

dIn recent years, there has been an average of roughly 300 foreigners per year who—on the basis

of having married U.S. citizens employed abroad—attained U.S. citizenship via a special

provision that allows naturalization of applicants who have not resided in the United States (see

INA section 319(b), 8 U.S.C. 1430(b)). Some of these persons may enter the United States—for

the first time—as naturalized citizens.

Source: GAO conceptualization.

Page 21 GAO/GGD-98-164 Quality of Immigration Statistics
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Policy-Related Information Needs

What is critical for policy analysts and for users of information is how

accurately measures of immigration reflect the actual patterns of

immigration (Kraly and Warren, 1992). The typology in table 2.1 represents

a step in the direction of measuring actual patterns and reducing

confusion. This is because the typology (or set of demographic categories)

can be used as a tool for sorting existing statistics and thus determining

where gaps exist. It can also help in the interpretation of information by

clarifying concepts such as the distinction between two types of flow. The

typology also makes plain the interrelationship of different kinds of

statistical information and helps clarify which statistics are directly

comparable and which are not.

A Consideration of

Policy-Related

Information Needs

A review of major immigration laws indicated that they often include

requirements for federal agencies to report information on flow, the size of

the foreign-born population, net change in size, and emigration. Notably,

the Immigration Reform and Control Act (IRCA) of 1986 requires triennial

reports to Congress,2

 which are to describe the number of persons who

are legally admitted or paroled into the United States within a specified

interval as well as those who illegally enter or overstay temporary visas

during that interval.3

 This corresponds to the demographic concept of

immigration flow. Note that with respect to illegal immigrants, it is

important to distinguish two different types of flow: those who “enter

without inspection” (EWIs) and those who overstay temporary visas. The

distinction is important from a policy perspective because, for example,

stronger border controls would not address the overstay issue.

IRCA also requires information on a variety of impacts of immigration,

including, for example, the impact on demographics and population size as

well as the impact on social services. We note that the impact on

population size would logically involve new entries, but not transitions

between legal statuses. The impact on social services would occur as a

result of both new entries and transitions of legal status—that is, both

types of flow—because the foreign-born resident’s specific legal status

determines whether or not he or she is eligible for specific benefits. (It is

2

P.L. 99-603, section 401, codified at 8 U.S.C. 1364.

3

Parole is permission to enter the United States and remain for an undefined temporary period for

humanitarian or public interest reasons. Information required for the triennial reports includes (1) the

number and classification of aliens (including nonimmigrants) who were admitted, paroled, or granted

asylum during the relevant period and (2) a reasonable estimate of the number of aliens who entered

the United States during the period without visas or who became deportable during the period under

[general classes of deportable aliens named in] section 237 (formerly, 241) of the Immigration and

Nationality Act, 8 U.S.C. 1237.

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Policy-Related Information Needs

important to note that although information on both types of flow

combined is relevant for certain policy purposes, data on combined-flow

to a legal status should be treated with caution. This is because it is not

always clear to what extent each type of flow is represented; e.g., a change

in a combined-flow statistic might reflect a change in the number of new

entries or a change in the number of transitions to the status in

question—or some combination of the two.)

With respect to the other relevant demographic concepts—the size of the

foreign-born population, net change in size, and emigration—the

Immigration Act of 1990 requires information on the alien population of

the United States as well as rates of emigration and an analysis of trends.4

Other laws, while not directly requiring statistical information,

nevertheless include mandates that imply such a need. For example, the

Illegal Immigration Reform and Immigrant Responsibility Act of 1996

mandates an evaluation of the effort to deter illegal entry into the United

States. Such an evaluation would require a variety of statistical

information, such as trends in the size of the illegal population (see

GAO/GGD-98-21).

There are other indications of the kinds of information that Congress has

wanted in recent years. For example, the House Judiciary Report

accompanying IRCA indicated that the requirement for the triennial reports

is intended to enable Congress to review and study immigration and

refugee programs and to consider possible changes to them with the

benefit of reliable and detailed data.5

 Congressional committees have

requested that we provide statistical estimates, such as projections of legal

immigration, to help in decisions regarding numerical limits.6

 Another

example would be the congressional request for estimates of the number

of certain nonimmigrant workers who transitioned to green-card status

(see GAO/PEMD-92-17).

Among the ongoing or recurring congressional activities for which the

types of information shown in table 2.1 might be useful are

4

P.L. 101-649, section 142, codified at 8 U.S.C. 1103(d).

5

H. Rept. 99-682(I) at 99 (1986).

6

In 1988 and 1989, we responded to congressional requests for projections of levels of future legal

immigration (GAO/PEMD-88-7, GAO/T-PEMD-89-1, GAO/PEMD-89-12, GAO/PEMD-90-5). In deciding to

change the annual numerical limits in the Immigration Act of 1990, Congress relied heavily on this

work (see Congressional Record, July 12, 1989, 14297-312).

Page 23 GAO/GGD-98-164 Quality of Immigration Statistics
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Policy-Related Information Needs

• periodic revisions of numerical limits for LPRs, annual setting of levels of

refugee inflow, periodic resetting of limits for certain temporary visas, and

annual prioritization of funding and special programs intended to reduce

illegal immigration;

• periodic redefinitions of (1) the conditions under which illegal immigrants

and others can (or cannot) adjust to LPR status and (2) ceilings on the

number of asylees who may transition or adjust to LPR status; and

• periodic revisions of public benefits available to persons in different

immigration statuses, which can in turn influence personal decisions

about changing one’s immigration status.

In addition, congressional committees have indicated that they wanted

information to address issues such as the impact of foreign workers on the

U.S. economy and on the working conditions of Americans (see, e.g.,

GAO/PEMD-92-17 and GAO/HEHS-98-20). There has also been some interest in the

trends in the numbers of naturalized citizens, because they have the right

to bring in certain relatives.7

7

Academic and government interest in this topic has been addressed in a series of articles in

International Migration Review. (For an overview of these articles, see Goering, 1989.)

Page 24 GAO/GGD-98-164 Quality of Immigration Statistics
Chapter 3 

Immigration Flow

INS’ annual Statistical Yearbook includes several statistics on immigration

flow—particularly, statistics on LPR flow (persons with new green-card

status), refugees and asylees, and naturalized citizens. But various quality

problems limit the utility of these data for policy purposes.

• Conceptual problems make a key trend difficult to interpret and valid

comparisons of certain reported data difficult to make; confused reporting

compounds the conceptual problems.

• Administrative data undercount persons granted asylum as well as those

attaining naturalized citizenship.

• Data gaps occur for key statistics, such as the number of foreign-born

persons who take up residence here each year.

The relevant statistics and descriptive quality ratings (together with the

reasons for our ratings) are presented in table 3.1.

The INS Yearbook includes several statistics that seemingly fit our typology

for information on immigration flow. As shown in table 3.1, these include,

for example, figures for the number of new LPRs who entered the United

States in fiscal year 1996 (421,405), the number of persons already here

who attained new green-card status (494,495), and the total number of new

LPRs (915,900). Similar kinds of data are reported for refugees and asylees

and for naturalized citizens (see rows B and E of table 3.1). The INS

Yearbook also discusses the sources of these data and some of their

limitations.

Few, if any, relevant data on flow are reported outside the Yearbook.

Page 25 GAO/GGD-98-164 Quality of Immigration Statistics
Chapter 3 

Immigration Flow

Table 3.1: Published Federal Statistics on Immigration Flow, With Descriptive Quality Rating and Reasona

Demographic concept: annual flow

Legal status of the

foreign-born

New residents (entered U.S.

during reference year)

Transitions to a new status

(during reference year)

Combined-flow to each status

(sum of first two columns)

A. Legal permanent residents 421,405 new LPRs 494,495 new LPRs 915,900 new LPRs

Overcount: Some persons

who transitioned to LPR status

(and belong in the next col.)

were counted here.

Undercount: Some persons

counted as new residents belong

here; also, processing slowdown

lowered the count.

Conceptual problem: The

majority of new LPRs were already

living in U.S., so the count does

not measure flow into the U.S.; in

1995 and continuing into 1996, a

processing slowdown affected the

count.

Confused reporting: INS

Yearbook highlights trends as if

meaningful; some statements in

the Yearbook imply that new LPRs

represent new entries.

B. Refugees and asyleesb 74,791 new refugees 18,556 new asylees 93,347 new refugees and asylees

Undercount: “Trailing

relatives” who enter the U.S.

as asylees are not counted in

the INS Yearbook.

Undercount: Persons granted

asylum on appeal and some

“trailing relatives” (who were

already in the U.S.) are not

counted in the INS Yearbook.

Undercount: Some asylees are

not counted.

C. Students, temporary

workers, and their families;

others temporarily here who

stayed > 1 yearc

No published estimate. No published estimate. No published estimate.

Gap: No data identify the

number new to the U.S. who

stayed 1 year.

Gap: No data identify the number

new to this category who were

already in the U.S.

Gap: No data identify the number

who stayed 1 year.

D. Illegal immigrants (EWIs

and overstays) who stayed

for > 1 year

No published estimate. No published estimate. No published estimate.

Gap: INS has not estimated

illegal flow.

Gap: INS has not estimated

illegal flow.

Gap: INS estimates net change in

the illegal population, but has not

estimated illegal flow.

E. Naturalized citizens Not applicable. 1,044,689 new citizens 1,044,689 new citizens

Not an entry statusd Undercount: Most minor

children are not counted.

Undercount: Most minor children

are not counted.

Total flow No published estimate. Total not meaningful because of

double-counting.

Total not meaningful because of

double-counting.

Gap: Because of gaps for

some categories, the total

cannot be tallied.

Some persons make more than

one transition in the same year.

Some persons enter the U.S. and

then transition to a different

status—within the same year.

(Table notes on next page)

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Immigration Flow

Legend

EWI Entry without inspection

LPR Legal permanent resident

Note: Statistics are not relevant to the shaded cells.

aFiscal year 1996.

bThe term “asylees” refers to persons granted asylum.

cOther foreign-born residents admitted temporarily include (1) trainees, treaty-traders, and

investors as well as their families; (2) special groups, such as those given temporary protected

status or extended voluntary departure; (3) parolees, that is, persons allowed to enter the United

States on a nonpermanent basis for urgent humanitarian reasons or when significant public

benefit is likely; and (4) persons entering on tourist or other short-term visas who nonetheless

remain in the United States longer than a year.

dIn recent years, there has been an average of roughly 300 foreigners per year who—on the basis

of having married U.S. citizens employed abroad—attained U.S. citizenship via a special

provision that does not require residing in this country (see INA section 319(b), 8 U.S.C. 1430(b)).

Some of these persons may enter the United States—for the first time—as naturalized citizens.

Sources: Published federal statistics on immigration flow are from INS 1996 Yearbook, for LPRs,

p. 52; for refugees and asylees, p. 85 (INS printed Department of State figures); for naturalized

citizens, p. 147. Ratings and reasons are based on interviews with INS, State, and EOIR staff,

information obtained from agency datasets, detailed information provided in the INS Yearbook,

and GAO analysis.

Conceptual Problems

and Confused

Reporting

Trends in the Number of

New LPRs

INS’ administrative count of the number of new LPRs combines the flow of

(1) new LPR entries to the United States and (2) transitions (or

adjustments) to LPR status. But there is a conceptual problem; namely, this

statistic represents two different measures, each of which can vary

independently. This makes results—particularly for trends—difficult to

interpret.

The majority of new LPRs are in category 2, transitions to LPR status. That

is, they are not new to the United States; as indicated in tables in the INS

Yearbook, they have already been living here for years—typically either

illegally or as long-term temporary residents. Various factors can raise or

lower the number of green cards authorized for such persons,

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Immigration Flow

independently of trends in new entries. Two instances show how this

can—and has—happened:

• The late 1980s amnesty (through IRCA) for illegal immigrants who had lived

here for more than 5 years created a sudden major upswing in the trend

line for new LPRs because a large group of illegal residents became eligible

to apply for green-card status. This increase was unrelated to any change

in the number of persons entering the United States.

• A recent change in law (1994) allowed illegal immigrants living in the

United States who qualified for green cards to transition to LPR status

without leaving the United States—thus shifting the processing of

thousands of cases from the Department of State to INS. Because INS could

not immediately handle the additional workload, there was a logjam, or

slowdown, in issuing the cards to persons already living here. The logical

effect of a slowdown is a decrease in the number of cards authorized (i.e.,

a downturn in the trend line), independent of any change in the number of

persons newly taking up residence in the United States. Subsequently, as

INS’ capacity to handle the new workload improves, a speed-up in

processing would increase the number of cards authorized for persons

already living here, creating an upswing in the combined-flow trend line.

INS statistical staff told us that annual trends in the number of new LPRs do

not convey a meaningful indication of any demographic concept.1

 They

also said it is unclear how to disentangle the effects of processing logjams

and catch-ups.

Despite these problems, INS has repeatedly highlighted annual trends in

“immigrants admitted” (what we term the combined-flow LPR statistic in

table. 3.1). The 1995 and 1996 INS Yearbooks lead off their introductions

with the first highlights of current findings, as follows:

• “720,461 persons were granted legal permanent residence status . . . a

decrease of nearly 84,000 from the year before” (INS 1995 Yearbook, p. 11).

• “915,900 persons were granted legal permanent resident status . . . an

increase of more than 195,000 over the year before” (INS 1996 Yearbook, p.

11).

In each case, the same page of the Yearbook interprets these trends as

either a “decline in immigration to the United States” (1995) or a “rise in

immigration to the United States” (1996). The introduction itself does not

1

One policy-relevant interpretation of this statistic would be the number of persons newly qualifying

for benefits accorded to LPRs.

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Immigration Flow

mention the recent processing problems or that any of the new immigrants

counted were already living here.

Readers who turn to the body of the Yearbook will find caveats. However,

although tables in the INS Yearbook indicate that the majority of new LPRs

were already living in the United States, the Yearbook text indicates only

that some were already here.2

INS statistical staff maintain that the agency never claims that the count of

newly authorized green cards represents a proxy for all new residents, but

the use of the term “admitted” may be confusing to some readers. Indeed,

the 1996 Yearbook makes the confusing statement that

“The majority of immigrants [LPRs] enter the United States as immediate relatives of U.S.

citizens or through the preference system, consisting of family-sponsored and

employment-based immigrants. These categories combined accounted for 78 percent of all

admissions in 1996.” (p. 18, emphasis added.)

A nonexpert might infer that “enter the United States” means exactly that,

not realizing that the majority of new LPRs were already here. (In other

words, some readers might not realize that the statement quoted above is

supposed to refer to persons entering LPR status—regardless of whether

they are already living here, as the majority are.)

Flow of Legals Versus Net

Change in Illegals

Another conceptual problem arises because the Yearbook presents

statistics relevant to flow for legal immigration—but an estimate for net

change in the illegal population. That is, the 1996 Yearbook reports that

nearly 1 million persons achieved green-card status in fiscal year 1996 and

that the population of illegals is increasing, on average, by 275,000 per

year. These two figures are not comparable, however, because flow is a

very different concept than net change. Briefly, the difference in concepts

is as follows:

• The flow of illegal immigrants refers to new illegal EWIs and overstays who

resided here for more than a year. (As shown in table 3.1, these two types

of flow can be described separately—and a combined number can be

provided.)

• Net change in the size of the illegal population is calculated,

mathematically, as the difference between (1) the flow of illegal residents

2

One sentence—in the 1996 Yearbook section, “Limitations of Data” (p. 24)—does mention the fact

that those who are transitioning or adjusting have often lived here for years.

Page 29 GAO/GGD-98-164 Quality of Immigration Statistics
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Immigration Flow

and (2) legalizations and other exits (emigration, death) from the entire

illegal population, as shown in figure 3.1.

• Net change may be a positive or negative number. When positive, net

change measures the extent to which the flow exceeds legalizations,

emigration, and deaths—on the part of the entire population of illegals

who were already living here. When legalizations, emigration, and deaths

outnumber the entries, net change is negative.

Legal flow cannot be validly compared to net change in the illegal

population. The fact that the INS Yearbook reports statistics relevant to

flow for legal immigration but net change for the illegal population is

compounded by the fact that the Yearbook does not discuss demographic

concepts. The Yearbook does not clarify the meaning of immigration flow

or net change in population size—or the distinction between the two.

Reporting flow for legals and net change for illegals, without clearly

distinguishing between flow and net change, could lead to

misinterpretations; that is, it might invite invalid comparisons. If a

comparison of legal and illegal immigration is to be made, the same

demographic concept should be used for data on legals and illegals; for

example, legal flow should be compared to illegal flow.

Page 30 GAO/GGD-98-164 Quality of Immigration Statistics
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Immigration Flow

Figure 3.1: Net Change in the Size of the Illegal Population

Source for net-change equation: Bogue et al., 1993.

This is important because numerically, the difference (illegal flow versus

net change in illegals) could be great. Large numbers of illegal immigrants

transition to green-card status (over 120,000 of those authorized to receive

green cards in fiscal year 1996 admit to having entered the United States as

EWIs), and the emigration of illegal immigrants may also be large. Thus, the

flow of illegal immigrants might—in some years—be considerably larger

than the reported net change in the size of the illegal population.

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Immigration Flow

Undercounts

Asylees Are Undercounted We found that INS Yearbook tallies of persons granted asylum are limited

to cases processed through INS’ RAPS (Refugee, Asylum and Parole System)

data system. Both RAPS and the Yearbook omit asylees whose cases were

approved by the Executive Office of Immigration Review (EOIR) rather

than INS.

3

 Both also omit asylees who enter from abroad after their

paperwork is approved by INS—trailing relatives of persons granted

asylum (i.e., family members “following to join” a principal asylee)—and

processed abroad either by the Department of State or INS.

4

 Also omitted

were other trailing relatives whose cases were processed in the United

States by INS (460 during the first four months of fiscal year 1996).5

Table 3.2 summarizes the count of asylees published in the INS Yearbook

and the additional counts that we were able to identify by talking with

various staff at Department of State, EOIR, and INS and by requesting

tabulations from various data systems. INS staff told us that in addition to

the 460 cases noted above, they estimate that approximately 1,000 more

were processed in the United States during fiscal year 1996; however, the

number of trailing relatives approved and processed overseas by INS during

fiscal year 1996 could not be estimated.

3

EOIR is within the Department of Justice, but is separate from INS. Asylum cases denied or referred

by INS are reviewed by EOIR immigration judges. EOIR provides a daily electronic transfer of records

to RAPS for administrative purposes. The INS Yearbook notes that asylees processed by EOIR are not

counted in the Yearbook’s tallies.

4

On behalf of INS, the Department of State processes “Visa 92” cases in areas where INS does not have

facilities. These cases include spouses and children who are in another country at the time when a

member of the family was granted asylum inside the United States (see 8 U.S.C. 208(b)(3)). Based on

an INS-approved petition, State issues travel papers to these spouses and children, allowing them to

come to the United States; once here, they are admitted with asylum status. We believe that, while

some of these spouses and children may not have actually come to the United States, most of them

likely came—because all of them were processed by the Department of State or INS (albeit in an

overseas location). They have not been included in any count reported in INS or State Department

publications—nor are they mentioned as omitted from relevant counts in the INS Yearbook.

5

Trailing relatives processed by INS are included in INS’ Computer Linked Application Information

Management System (CLAIMS). Although INS could identify 460 trailing relatives that were processed

in the United States during the first 4 months of fiscal year 1996, INS was not able to identify other

cases of asylee approval that were included in the CLAIMS system. The 1996 Yearbook does not report

that its tallies omit these asylees.

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Immigration Flow

Table 3.2: Persons Granted Asylum

and Whether Included in Yearbook

Count (FY 1996) 

Included in count? Number new asylees Agency data source

Yes 18,556 INS

No 5,096 EOIR

3,652a State

1,460 + an additional

unknown numberb

INS

Subtotal 10,208 + an additional

unknown number

INS, State, EOIR

Total 28,764 + an additional

unknown number

INS, State, EOIR

Legend

EOIR = Executive Office of Immigration Review, Department of Justice

INS = Immigration and Naturalization Service

aThese 3,652 cases were approved by INS and processed overseas by the Department of State

for admission to the United States with asylum status. State told us that in most instances, a case

represents an individual person, but there may be exceptions (i.e., instances where a single case

represents multiple persons).

bINS approved 460 trailing relatives in the United States during the first 4 months of fiscal year

1996, and estimates that approximately 1,000 more were approved during the remaining 8

months. The additional unknown number represents an unknown number of trailing relatives

whose cases INS processed overseas for admission to the United States with asylum status.

Source: GAO analysis of INS, State Department, and EOIR data for fiscal year 1996.

In sum, the count of asylees published in the INS Yearbook should be

increased—probably by more than 50 percent (i.e., from 18,556 to 28,764

or perhaps to an even higher figure). The undercount is not fully described

in the Yearbook, apparently because the administrative processes are

complex and it is difficult to identify all cases in which asylum was

granted. By contrast, however, we found no biases in the Department of

State counts of refugees reported in the INS Yearbook.

Naturalized Citizens Are

Undercounted

The number of naturalizations reported by INS (row E of table 3.1) is an

undercount of new foreign-born U.S. citizens because the tally excludes

most minor children. That is, as explained in the INS Yearbook, minor

children automatically receive citizenship (by derivation) when their

parents naturalize.6

 A separate form is not required for these children, and

they are not listed on their parents’ forms. INS counts persons listed on

forms; a complete count cannot be obtained without revising the existing

6

Under section 320 of the Immigration and Naturalization Act (8 U.S.C. 1431), a child automatically

becomes a naturalized citizen if he or she is under 18 years old and is living in the United States

pursuant to lawful admission for permanent residence at the time of naturalization.

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Immigration Flow

form. (We also note that trends in naturalization are affected by processing

speed-ups and slowdowns similar to those discussed above for LPRs. As of

July 1998, the logjam for naturalization applications was estimated to be

between 1.6 and 2 million unprocessed applications.7

)

Transitions to LPR Status

May Be Undercounted

Transitions to LPR status may be undercounted. INS statistical staff told us

that in 1996, transitions to LPR status apparently continued to be deflated

(to some extent). That is, even after the change in law allowing illegal U.S.

residents to transition to green-card status without leaving and reentering,

some continued to exit and reenter—preferring the travel to paying the fee

required for transitioning without leaving. Although this number may be

relatively small, it represents a subtraction from the transitions column

and an addition to the new entries column—thus distorting what is

reported about patterns of flow to some extent.

Data Gaps

Gap for Flow of Long-Term

Residents Admitted With

Legal Temporary Status

There is a gap in flow statistics for residents who are admitted with

temporary visas (i.e., nonimmigrant visas, such as student visas, temporary

work visas, and so forth). The gap occurs because the relevant INS data

system does not distinguish newly admitted persons from readmissions of

the same person. For example, a foreign student living here for 4 years but

visiting his parents briefly every 6 months would be represented as eight

short stays—for up to eight individuals—rather than one long stay for a

single person. Thus, although durations of stay have been calculated (INS,

1996; Lowell, 1996), they do not correspond to the flow of long-term

residents who were admitted with legal temporary status. Moreover,

problems at INS or with INS contractors (including computer-processing

problems and lack of agreement on what constitutes a valid match) have,

since 1992, prevented calculations involving matched entries and exits.

And with respect to this and other data systems, INS statistical staff told us

that there had been no recent audits or evaluations to test the level of

error in data processing and data archiving. Such work might reveal, for

example, whether double-counting or lost cases occurred.

Department of State information on issuances of temporary visas cannot

fill this gap for two reasons. First, in some cases, a visa allows multiple

7

The logjam occurred because of an unprecedented increase in applications for citizenship. The

process of rolling out new fingerprinting procedures may have also contributed to the slowdown.

Page 34 GAO/GGD-98-164 Quality of Immigration Statistics
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Immigration Flow

entries and exits, whereas other visas allow only a single entry so that a

new visa is required for each entry and exit. There is no direct

correspondence, then, between the number of visas issued and the

number of new residents with visas. Second, a single person can, if

qualified, be issued multiple visas in different categories—for example, a

temporary work visa and a tourist visa could be issued to the same person

on the same day—and it would be very difficult to cross-reference records

for statistical purposes.

We believe this gap is important because the number of long-term

residents living here with temporary visas may be quite large. One analyst

(Woodrow, 1998) puts the flow of nonimmigrant residents into the United

States at approximately 1 million, perhaps more, in 1990. Under alternative

assumptions, possible figures for fiscal year 1996 might range from very

roughly 500,000 to 1 million, but the true dimensions are unknown.8

Gap for Total Flow of

Foreign-Born Residents

Into the United States

From the perspective of charting the overall impact of immigration on

American society, the most important statistic for which there is a gap

may be the total number of new entries who take up residence in the

United States each year (total for col. 1 in table 3.1). To fill this gap would

require dealing with the gaps and biases in the various estimates for new

entries in the various legal status categories: LPRs; refugees and asylees;

foreign students, temporary workers, and others here legally for a

nonpermanent stay; and illegal residents. Indeed, approximate figures

developed for lower and upper bounds could differ by as much as one

million persons—leaving policymakers still without a proper information

base.9

8

Our analysis—listing all sources of nonimmigrant flow, using what data were available for 1996 and,

where necessary, making assumptions concerning minimum numbers—suggests that the annual flow

of nonimmigrant residents could easily be over 500,000 and might be considerably higher. However,

unsubstantiated assumptions were sometimes necessary; e.g., in making minimum and maximum

calculations, we assumed that between 35 and 80 percent of the student visas issued by the State

Department represented a new resident who remained for over a year.

9

We attempted to develop approximate figures by listing all relevant categories, using what data were

available for each and, where necessary, making assumptions for lower and upper bounds. We did not

report the specific figures because of their speculative nature.

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The Resident Foreign-Born Population: Size,

Net Change, and Emigration

The Bureau of the Census provides decennial census and intercensal

survey data on the size of the foreign-born population and change in size,

and it estimates emigration. Although there are no directly relevant

administrative records, INS provides some additional information through

“composite estimates.”1

 Overall, information on the size of the

foreign-born population, change in size, and emigration is limited, as

summarized in table 4.1. There are two main reasons for this:

• Decennial census and survey estimates apply only to total foreign-born

and naturalized citizens (rows E and total in table 4.1).2

 For specific legal

statuses, there are gaps and uncertain estimates (rows A through D in

table 4.1). Aside from a question on U.S. citizenship, the census and

intercensal surveys do not ask about legal status. (One reason is that

questions on the respondent’s legal status are very sensitive and might

result in biased answers or affect responses to other questions.) INS efforts

to fill data gaps without additional data collection efforts have resulted in

uncertain estimates.

• The data provided by Census for total foreign-born and naturalized U.S.

citizens have not been rigorously evaluated. The unevaluated estimates are

at least somewhat uncertain because of the questions about adequate

coverage of the foreign-born population and other quality issues that have

been raised by a number of analysts. Moreover, problems have cropped up

in estimating emigration—and also in reliably quantifying net change.

We also found that the information in table 4.1 cannot be accessed by

referring to just one or two publications. Rather, policymakers and other

information consumers must first identify and access a variety of sources

(including the Internet), then piece results together—with no guide to

their comparability.

1

We define “composite estimates” as those made in the absence of direct data. Such estimates draw on

what data are available—often a combination of different kinds of data and/or different kinds of

estimates—plus major assumptions. (By major assumptions, we mean assumptions that can have

important impacts on the estimates.)

2

Census and survey estimates for total foreign-born would logically include residents in all major legal

statuses, including those with temporary legal status as well as illegal immigrants. We believe that such

estimates of total foreign-born are probably generally consistent with our definition of foreign-born

residents—that is, persons living here who either (1) are in a permanent legal status or (2) if in a

temporary legal status or here illegally, remain in the United States for more than a year.

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Table 4.1: Published Federal Statistics for Three Demographic Concepts, Descriptive Quality Rating and Reason, 1996a

Population size Net change in size Annual emigration

Demographic concept

Legal status of foreign-born

Number of foreign-born

persons residing here (at

given point in time)

Annual increase or decrease

in the size of foreign-born

population

Number of foreign-born

residents who left the U.S.

(calendar 1996)

A. Legal permanent residents 10,525,000 LPRsb No published estimate. No published estimate.

Uncertain: Composite estimate

requires major assumptions.

Gap: No administrative or

survey data.

Gap: No administrative or

survey data.

B. Refugees and asylees

(without LPR status)c

No published estimate. No published estimate. No published estimate.

Gap: No comprehensive

administrative data; questions

about legal status deemed too

sensitive to ask survey

respondents.

Gap: No administrative or

survey data.

Gap: No administrative or

survey data.

C. Students, temporary

workers, and their families;

others here temporarily who

stayed >1 yrd

No published estimate. No published estimate. No published estimate.

Gap: No usable administrative

data; questions about legal

status too sensitive to ask in a

survey.

Gap: No administrative or

survey data.

Gap: No administrative or

survey data.

D. Illegal immigrants (EWIs

and overstays) who stayed

> 1 year

5 million EWIs and overstayse 275,000 more illegal residentsf No published estimate.

Uncertain: Composite estimate

requires major assumptions.

Uncertain: Composite estimate

requires major assumptions.

Gap: No administrative or

survey data.

E. Naturalized citizens 7.9 million naturalized citizensg 1.1 million more naturalized

citizens (3/97 versus 3/96)h

300,000 more naturalized

citizens (3/96 versus 3/95)i

No published estimate.

Unevaluated: Survey estimate

is disputed in literature owing

to possible overreporting of

citizenship not firmly resolved.

Uncertain: These survey

estimates involve time lag in

reporting.

Gap: No administrative or

survey data.

Total 24.6 million foreign-born

residentsj

1.2 million more foreign-born

residents (3/97 versus 3/96)k

0.1 million more foreign-born

residents (3/96 versus 3/95)l

No published estimate.

Unevaluated: Analysts have

raised questions about survey

estimates’ underrepresentation

of newcomers, etc.

Uncertain: Survey estimates of

year-to-year change are

imprecise.

Gap: Census first said estimate

of emigration (195,000) referred

to all foreign-born; Census now

says it refers to emigration of

legal residents only.

(Table notes on next page)

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Net Change, and Emigration

Legend

EWI Entry without inspection

LPR Legal permanent resident

aThe three demographic concepts are size of the foreign-born population, net change in size, and

emigration.

bAs of Apr. 1996; range: 10.175 to 10.875 million LPRs.

cThe term asylees refers to persons granted asylum.

dOther foreign-born residents admitted temporarily include (1) trainees, treaty-traders, and

investors as well as their families; (2) special groups, such as those given temporary protected

status or extended voluntary departure; (3) parolees, that is, persons allowed to enter the United

States on a nonpermanent basis for urgent humanitarian reasons or when significant public

benefit is likely; and (4) persons entering on tourist or other short-term visas who nonetheless

remain in the United States longer than a year.

eAs of Oct. 1996; range: 4.6 to 5.4 million EWIs and overstays; best estimate for EWIs (only),

2.9 million; best estimate for overstays (only), 2.1 million. (Note: These INS estimates of EWIs and

overstays include some persons who were illegal immigrants but attained a special category

status, such as extended voluntary departure.)

f

Annual average increase (1992-96) in EWIs and overstays combined. (Note: These INS estimates

of EWIs and overstays include some persons who were illegal immigrants but attained a special

category status, such as extended voluntary departure.)

gAs of Mar. 1996; 90-percent confidence interval: 7.5 to 8.3 million naturalized citizens.

h90-percent confidence interval: 680,000 to 1.6 million more naturalized citizens.

i

90-percent confidence interval: 240,000 fewer to 800,000 more naturalized citizens.

j

As of Mar. 1996; 90-percent confidence interval: 23.9 to 25.3 million foreign-born residents.

k

90-percent confidence interval: 460,000 to 1.99 million more foreign-born residents.

l

90-percent confidence interval: 720,000 fewer to 840,000 more foreign-born residents.

Source: Published federal statistics on the foreign-born are from the INS Web page; INS

Yearbook, pp. 197-98; Current Population Reports, Bureau of the Census, Mar. 1997; Schmidley

and Robinson, 1998, table A3. Additionally, the confidence intervals in notes to this table were

provided to us by the Bureau of the Census. The ratings are based on agency interviews, review

of the literature, and logical analysis.

The Available Data The Alien Address Report Program (an annual registration system

maintained by INS) was discontinued in 1981. Until its demise, that system

was a source of administrative data on the population of legally resident

aliens (i.e., noncitizens). Since all resident aliens were required to register,

the number living here would be represented by the number

registering—provided that all legal aliens complied. The registration

system was discontinued partly for budgetary reasons, but also because

not all aliens reported, and the value of the information was unclear.

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The Resident Foreign-Born Population: Size,

Net Change, and Emigration

Likewise, administrative systems to record emigration by aliens and U.S.

citizens, begun early in this century, were discontinued (in the 1950s)

partly because they were believed to underestimate permanent departures.

After the Alien Address Report Program was discontinued, the decennial

census represented, until recently, the only remaining regularly scheduled

collection of data on the size of the foreign-born population. Occasional

supplements to the Current Population Survey (CPS) included questions on

nativity and citizenship. Then, starting in 1994, such questions were added

to the CPS on a regular basis, providing information on the foreign-born

population in intercensal years.3

Gaps and Uncertain

Estimates

Lack of Census and Survey

Data on Legal Status

Neither the census nor the CPS asks about the legal status of

noncitizens—or whether they are, in fact, here illegally. There are good

reasons for this: such questions fall under the heading of “threatening”

survey questions (Bradburn and Sudman, 1979); many respondents might

not answer these questions truthfully; and others might avoid participating

altogether if they hear that such questions will be asked. In addition, the

Bureau of the Census is concerned about privacy invasion issues.4

Uncertain Composite

Estimates

In an effort to fill data gaps, INS developed “composite estimates” for the

number of illegal residents and for the number of legal permanent

residents. Although these estimates represent a step forward (because

they provide some information that would otherwise not be available),

they are necessarily uncertain. That is, it is difficult to determine whether

the figures might be underestimates or overestimates and to judge what

the magnitude of misestimation might be.

3

Concurrent with the addition of these questions to the CPS on a regular basis, cognitive interviewing

was conducted to evaluate and improve the questions on nativity and citizenship. (Cognitive

interviewing is a method of testing how respondents interpret survey questions; e.g., a test respondent

is asked to “think aloud” while coming up with an answer to a question. The results are used to revise

questions, as needed, in order to more clearly communicate with respondents.)

4

The Bureau is concerned that its role not include obtaining (and maintaining) potentially damaging

information from survey respondents or persons who cooperate in a decennial census.

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Net Change, and Emigration

INS’ composite estimate of the current number of illegals residing here is

based mainly on the following three calculations—each of which is

characterized by uncertainty:

• First, INS calculates an estimate of illegal “overstays”—persons who

entered legally on a temporary basis and failed to depart. These estimates

are uncertain for several reasons: INS’ data system does not track many

legal entries by Mexicans and Canadians (Department of Justice, 1997); so

if such persons overstay, they would not be counted. Although the system

records other persons’ legal entries and departures, a substantial portion

of the departure data is missing each year, and the assumptions INS uses to

differentiate missing departure data from actual overstays are

controversial.5

 Moreover, INS made its current (1996) estimate by

projecting old overstay estimates forward (Department of Justice, 1997).

(Data collected after 1992 are deemed not usable because of computer

processing problems and lack of agreement on what constitutes a valid

match.)

• Second, INS calculates the total number of Mexican illegals by comparing

administrative data on Mexican legal immigrants to CPS data on total

Mexican foreign-born. Here, uncertainty derives from not knowing survey

underrepresentation of illegals and from questions about the estimate of

emigration (see INS Yearbook).6

• Third, INS estimates the number of non-Mexican residents who “entered

without inspection” (i.e., EWIs from other countries around the world)

based on a variety of data, including data from the late 1980s amnesty (that

IRCA provided) as well as more recent data on trends in apprehensions.

Translating such data into an estimate of the number of current residents

necessarily involves assumptions and uncertainty.7

Turning to the size of the LPR population, this INS estimate is based on an

indirect method that includes subtracting the estimated number of

illegals (just discussed) from the number of foreign-born aliens (i.e.,

noncitizens) estimated in the CPS. Thus, the uncertainties regarding the

estimate of illegals are necessarily carried over to the estimate of the

number of foreign-born residents with green cards.

5

For a critique of INS’ method of calculating overstays, see GAO/PEMD-95-10.

6

The Mexican overstay data are used to divide the estimate of total Mexican illegals into overstays and

EWIs.

7

We also note that the INS estimate of illegal immigrants includes some persons in special categories

(such as temporary protected status) whom we have included as long-term temporary residents.

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The Resident Foreign-Born Population: Size,

Net Change, and Emigration

With respect to the INS estimate of net change in the size of the illegal

population from year to year (275,000), we note that this estimate is

derived by comparing composite estimates for two points in time

(October 1992 and October 1996) and dividing the total change into equal

amounts of change for each year.8

 Hence, this estimate is marked by the

uncertainty of the composite estimates of the size of the illegal population.

It also reflects a general level of change rather than depicting current

trends.

Existing Census and

Survey Data: Lack of

Evaluation

Valuable as the census and CPS data are—or can be—for estimates of the

size of the foreign-born population and other demographic concepts,

various analysts have raised questions about quality. The Bureau of the

Census believes that the foreign-born are less likely to be enumerated than

the native-born, but a rigorous evaluation has not been conducted.

Questions About

Underrepresentation of the

Foreign-Born in the Census

The Bureau of the Census has carefully evaluated the quality of 1990

census data in the Post Enumeration Survey (PES), but the PES does not

distinguish foreign-born residents from native-born. A wide variety of

factors have been hypothesized—or identified in indirect analyses and

qualitative studies—as contributing to underrepresentation of the

foreign-born (see table 4.2). However, it is also possible that reverse errors

could occur (Jasso and Rosenzweig, 1987; Schmidley and Robinson, 1998),

and in the absence of a rigorous evaluation targeting the foreign-born, the

level of net underrepresentation is unknown. For the 1990 census as a

whole, however, a rigorous evaluation indicated that undercounting was

the more important factor. (For a discussion of the net undercount in the

1990 census and the gross levels of overcounting and undercounting that

occurred, see GAO/GGD-91-113.)

8

The INS estimates are for all illegals; the Bureau of the Census estimates annual net change for the

counted population of illegals.

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The Resident Foreign-Born Population: Size,

Net Change, and Emigration

Table 4.2: Reasons for

Underrepresentation of Foreign-Born

in a Census or Survey and Type of

Evidence

Reason

Type and source of

evidence

Some long-term residents (e.g., those here on temporary

visas) may not identify the United States as their usual

place of residence—and thus would be omitted from the

census.

Hypothesis (Hollman, 1997;

Passel and Clark, 1998)

In ad hoc households of recently arrived illegal immigrants

with no special ties to each other, omissions on the

household roster are more likely; in extreme cases, more

than 10 men might share a single unit—working and

sleeping in shifts. Indeed, the person speaking with the

enumerator may not really know who else lives there.

Qualitative studies (de la

Puente, 1993; Velasco,

1992)

Some illegals intentionally avoid enumeration. Qualitative study (de la

Puente, 1993)

Recent immigrants are likely to be boarders in the homes of

a more established immigrant family—and thus may be

omitted from household rosters. Also, Mexicans from

villages do not recognize the Spanish word for boarders

(“inquilinos”), which is used in surveys; they use the

“Spanglish” term “renteros.”

Small qualitative studies

(McKay, 1993; McKay et al.,

1996)

Some immigrant households are hidden from enumerators,

such as when a newly arrived family rents a back bedroom

in an apartment—in violation of the lease—and the lease

holder omits the extra persons when enumerating the

household. Other examples include families in hidden

makeshift shacks, converted garages, or colonias

(shantytowns that lack streets, electricity, and other

services).

Qualitative studies

(Gabbard et al., 1993; de la

Puente, 1993; Davies, 1995;

Chapa and del Pinal, 1993)

Some Mexican immigrants may falsely claim U.S. birth. Demographic analysis

(Warren and Passel, 1987;

Woodrow, 1991; Woodrow

and Passel, 1990)a

aAs an example of demographic analysis, Woodrow used the number of Mexican-origin U.S.-born

persons reported in, e.g., 1980 and data on subsequent U.S. births to derive an expected level of

increase in the Mexican-origin U.S.-born population as of, e.g., 1989. The expected increase was

compared to survey data collected in 1989. An unexpectedly high number of Mexican-origin

persons claimed U.S. birth in the 1989 survey—a pattern that might be explained by immigration

combined with false reports of U.S. birth.

Underrepresentation is thought to be concentrated in certain groups of the

foreign-born, such as newcomers and illegals, who currently constitute

perhaps one-fifth of all foreign-born residents. Unofficial estimates by

Census staff put the undercount of illegal immigrants at about 33 percent

in the 1980 census; Passel (1986) has suggested a range between 33 and

50 percent. For the 1990 census, various anaylses put the figure at roughly

20-30 percent (Woodrow, 1991; Van Hook and Bean, 1997; WoodrowLafield, 1995.)

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Possible

Underrepresentation of the

Foreign-Born in the CPS

Post Enumeration Survey results are used to adjust the Current Population

Survey for misrepresentation of specific groups defined by age, sex, race

or Hispanic origin, and state of residence. However, it is not known

whether the PES adjustments sufficiently improve representation of the

foreign-born. If there were no differences between the coverage of

foreign-born and native-born persons of the same age, sex, race, and so

forth, the PES adjustments should produce accurate CPS estimates of the

foreign-born. But as delineated in table 4.1, foreign-born persons may be

less likely to be found or identified as residents than native-born persons

are, and it is possible that some foreign-born persons may also falsely

claim U.S. birth. Thus, despite the PES adjustments, the CPS data could

underrepresent the foreign-born.9

A different issue could contribute to added underrepresentation of the

foreign-born in the CPS: survey nonresponse. As in any survey, some

sampled CPS households do not respond to the CPS.

10 CPS response rates are

calculated (and adjustments to correct for nonresponse are applied) to

geographically large areas—on average, about five areas per state.11 If

foreign-born residents are as likely to respond to the CPS as native-born

persons who reside in the same area, there is no problem. But this may not

be the case; possible reasons for lower response rates among certain

groups of foreign-born include interviewer problems communicating with

non-Hispanic immigrants; possible distrust of government or strangers

among certain groups (those illegally here, asylees from repressive

countries); and for some groups of new immigrants, less familiarity with

polling. Thus, higher rates of nonresponse among the foreign-born may

contribute to underrepresentation. (An analysis of nonresponse in

subareas where foreign-born are concentrated would settle the issue.)

Questions About the

Estimation of Naturalized

Citizens

Turning to estimates of the number of naturalized citizens, the main

concern is not with undercoverage (because citizens are likely to be

counted) but rather with the potential for overrepresentation because of

false claims of citizenship. This issue is currently being disputed in the

literature (Passel et al., 1998; Schmidley and Robinson, 1998). We also note

9

When using CPS data on Mexicans to estimate illegals, the Commission on Immigration Reform and

Secretaria de Relaciones Exteriores (1997) used an additional adjustment to correct for

underrepresentation.

10The CPS nonresponse rate is less than 10 percent overall, including foreign-born and native-born. It is

known to differ by geographic area; e.g., Los Angeles has a much higher nonresponse rate than Seattle.

11To illustrate how weights compensate for nonresponse, data from three areas with response rates of

100, 90, and 50 percent would receive relative weights of 1, 1.1, and 2, respectively.

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that the CPS, which reinterviews respondents over a 16-month period, has

thus far asked the citizenship question only at the first interview.

Consequently, the CPS estimates omit some of the most recent naturalized

citizens. Currently, this is important because of large numbers of

naturalizations—over 1 million persons were naturalized in fiscal year

1996. The Census Bureau is now considering asking the citizenship

question in every CPS interview.

Imprecision and Possible

Volatility in Estimates of

Year-To-Year Change

Census staff have stated that “The CPS nativity data provide a reliable basis

for tracking change in the size of the total foreign-born population at the

national level” (Schmidley and Robinson, 1998, p. 17). But various Census

staff told us that year-to-year change in the size of the total foreign-born

population could—and alternatively that it could not—be reliably

measured by CPS data. Current estimates of year-to-year net change in the

size of the foreign-born population (see table 4.1, total row) seem

imprecise; indeed, the confidence intervals are so broad that the estimates

might be deemed too imprecise for policy-making purposes. For example,

as shown in table 4.1, the 90-percent confidence interval for 1996-97 net

change in the size of the foreign-born population ranges from an increase

of under a half million to an increase of about 2 million. In other words,

the foreign-born population (24 million) may have increased by as little as

2 percent or as much as 8 percent—in a single year.

At our request, Census staff prepared an “annual averages” estimate for

the 1996 to 1997 change.12 The annual averages estimate is, again, an

increase of 1.2 million; the confidence interval (800,000 to 1.7 million) is

smaller, but still seems imprecise.

It is also somewhat troubling that the trends in year-to-year change appear

to be volatile—going from near zero in one year to an increase of over a

million the next. It is not known whether some degree of real change

occurred, whether an artifact caused the result, or whether the very large

difference in estimates is simply from sampling error.

Problems in Estimating

Emigration

In using 1980 and 1990 census data to estimate emigration of foreign-born

persons, analysts at the Bureau of the Census encountered inconsistent

12Such an estimate is more stable because it draws on larger samples—i.e., it includes the responses of

all persons interviewed throughout the 12 months of each year. A separate estimate of the size of the

foreign-born population is prepared based on data for each month of the relevant year, and then an

average is taken across all 12 months. This is done separately for each year, and the difference

between the years is calculated.

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results—apparently because of coverage problems. Bureau of the Census

analysts attempted to estimate emigration by tracking arrival cohorts—for

example, Mexicans who came to the United States to live during the

1970s—across the 1980 and 1990 censuses. The logic was that by

observing the extent to which the size of a cohort dwindled between 1980

and 1990 (while accounting for deaths), one could infer the level of

emigration.13 The approach is logical and reflects basic procedures of

demographic analysis. But no dwindling was apparent for Mexico and

several other countries; instead, cohorts that arrived in the 1970s appeared

to grow between 1980 and 1990, thus yielding negative estimates of

emigration—a logical impossibility.14

Census staff determined that data for certain countries were unusable, and

emigration rates were calculated only for residents from countries with

usable data (such as Spain). These rates were then extrapolated to

countries with unusable data (such as Mexico).15 The result was an

estimate of 195,000 emigrants each year. But a number of uncertainties are

involved; notably, emigration rates may differ for legals and illegals, and if

so, extrapolation from countries such as Spain (with mostly legal entries)

to countries like Mexico (with large numbers of illegal entries) would be

inappropriate. Census staff have recently determined that—in

hindsight—the 195,000 is best interpreted as an estimate of emigration on

the part of legal foreign-born residents only.16 One possible problem with

this interpretation is that in calculating the 195,000, the Bureau

extrapolated emigration rates to all foreign-born residents—a group that

includes some illegals.17

13An estimate of deaths is subtracted out.

14A similar pattern appears to hold for the 1990s. That is, a recent paper by Census staff indicates that

for Mexico and other countries in this hemisphere, the number of persons who say they arrived before

April 1990 appears to have grown slightly (rather than dwindled) between the 1990 census and the

1997 CPS (see table A.10 of Schmidley and Robinson, 1998).

15Specifically, it was assumed that the emigration rate for residents from countries such as Mexico was

half that for countries such as Spain or Argentina (chiefly because economic conditions in countries

like Mexico make returning there less attractive).

16The Census paper containing the 195,000 figure does not state this qualification, which emerged only

after we questioned staff about their figure for net migration. The estimate of 195,000 is used in

calculations of net migration that are used in intercensal estimates of the total population (and are

control totals for the CPS). In those calculations, the 195,000 estimate is treated as an estimate of

emigration by legals (see Hollman, 1998).

17Census staff agreed that a small number of emigrating illegals were included in the 195,000; they

believed that the resultant overestimation of emigrating legals was probably small.

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Reporting Data on

Size of the

Foreign-Born

Population, Change in

Size, and Emigration

A policymaker or interested member of the general public would have to

access four disparate sources to obtain the estimates shown in table 4.1:

(1) the 1996 INS Statistical Yearbook, (2) the INS Web page, (3) an issue of

Current Population Reports, and (4) a Bureau of the Census “working

paper” on trends and methodological issues. In no case does any one

publication refer to all the others, and we could find no central source

pointing the interested person to all four. In some cases, less widely

distributed publications are needed to understand the methodological

bases of the figures. The lack of a central publication relating the results

found in one source to those found in another means that readers must

gauge the relative quality and comparability of the various estimates, and

their interrelationship, for themselves.

In some cases, reporting has not provided the complete information that

readers need to judge the quality or stability of the estimates. For example,

the Bureau of the Census working paper, entitled “How Well Does the

Current Population Survey Measure the Foreign-born Population in the

United States,” reports that the nonresponse rate for the CPS is about

6.5 percent, but does not let readers know whether the level of response

for communities or areas dominated by foreign-born residents is roughly

the same as for other areas. To cite another example, the description of

the estimates of illegal overstays in the INS 1996 Statistical Yearbook fails

to inform readers that data on overstays have not been available since

1992 and that the 1996 estimates of illegals were achieved by projections

of data from earlier years.

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INS has some initiatives underway to fill data gaps, including an attempt to

develop a measure of illegal flow into the United States. In addition, we

have identified strategies to improve census and survey data on the size of

the foreign-born population. These include (1) eliminating data gaps by

collecting survey information on immigration status through a less

sensitive form of questioning—the three-card method—and (2) achieving

greater certainty for estimates of total foreign-born and naturalized

citizens through evaluative analyses, and where needed, corrective

adjustments.

Current Initiatives for

Improving

Information

A number of new initiatives are underway at INS. Notably, INS is attempting

to improve its data on foreign students—a key group of long-term

temporary residents. INS is also attempting to develop a measure of illegal

flow into the United States and a new measure of the size of the illegal

population. These initiatives do not address all of the problems identified

in chapters 3 and 4, however.

• For foreign students, INS has created a new approach to record-keeping

that should allow estimates of the number of new students who come to

reside here each year, the size of the student population, and net change in

size. A unique high-tech identification card (with digitally encrypted

identifying information) is prepared for each student in advance and

issued to him or her upon arrival in the United States. The special card is

used for each entry and exit. INS is pilot-testing that approach by tracking a

group of 10,000 students—that is, following them individually across

time—from prearrival through years of schooling, including exits from the

United States and reentries.1

 (Roughly a half-million students resided here

during the 1995-96 school year; U.S. Department of Education, 1997.)

• To fill the information gap for illegal flow, INS is currently working to

develop a new composite estimate. The new estimation method will utilize

CPS data on the number of foreign-born residents and their reported year of

1

Improved tracking is not only a statistical issue. Tracking of persons here on student visas is also of

concern from a law enforcement and intelligence perspective (see Hearing before the Senate

Subcommittee on Technology, Terrorism, and Government Information, Committee on the Judiciary,

Feb. 24, 1998). Tracking of tourist entries and exits is also needed to monitor the Visa Waiver Pilot

Program, which allows tourists from several foreign countries to visit the United States without a visa.

By law, the waiver for an individual country must be revoked if the number of overstays exceeds 2

percent of tourist entries. (See GAO/PEMD-95-20 and U.S. Department of Justice, 1997.)

INS also told us that it (1) is pilot-testing an automated entry-and-exit tracking system for all classes of

nonimmigrants at two airports (and is planning to expand this test to 10 airports) and (2) is continuing

its attempts to solve the computer and other problems that have prevented reliable matches of entries

and exits since 1992. However, even if successful, these efforts would not address the issue of

distinguishing reentries from new entries—which is crucial for estimating the number of foreign-born

persons who newly take up residence here each year.

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entry to the United States. It will also utilize INS administrative records for

data on the number of new legal residents. Assuming that the method is

successful, it will produce estimates of flow and trends in flow that

include both EWIs and overstays who remain in the United States longer

than a year. (The new method will not provide separate estimates for the

flow of EWIs and the flow of overstays, however.) The approach also

produces an estimate of the size of the illegal population without relying

on the usual overstay data.

With respect to improving the reporting of information on flow, INS

statistical staff told us that, intermittently, they have discussed plans for

an analytic report that is oriented to policy-information needs. However,

due to lack of staff time, such plans have always been shelved.

We know of no new initiatives or special analyses being conducted or

planned at the Bureau of the Census. The agency told us that its budget

and mission do not allow substantial resources to be devoted to estimates

of the foreign-born. However, Census also told us that if the planned

American Community Survey is implemented, it will include questions on

nativity and U.S. citizenship. The resulting estimates of the foreign-born

population would be more stable than CPS estimates because a very large

sample is planned for this survey. (Statistically, the larger the sample, the

more likely it is that the resulting estimate will fall close to the value that

would be obtained in a complete census.)

Strategies for

Improving Census and

Survey Data on the

Foreign-Born

Strategies for improving census and survey information include

(1) research on a new survey technique that asks less sensitive questions

about immigration status (the three-card method) and (2) low-cost

evaluations of existing census and survey data on the foreign-born.

Survey Data to Fill Gaps

for Legal Status: the

Three-Card Method

To confirm or improve existing uncertain estimates—and to fill data

gaps—we determined that a new approach to asking survey respondents

about their legal status might be helpful. Previously developed methods

for reducing question threat and protecting respondent privacy (see app.

III) do not seem suitable for use with the foreign-born population. We

therefore devised a new method that builds on earlier techniques but

requires no unusual interview procedures. We discussed this method

(which we term the three-card method) with INS staff and with officials

and staff at the Bureau of the Census. We also discussed it with a number

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of statistical and survey experts. And we conducted a preliminary

qualitative test of its acceptability to respondents and interviewers.

The three-card method is designed to encourage truthful responses

concerning legal status—yet no foreign-born person need reveal whether

he or she (or anyone else) is an illegal immigrant. Indeed, no one could

ever discover, even through a series of deductions, whether a respondent

was here illegally. Yet when all data are combined, survey-based estimates

are available for all legal statuses—including illegal immigrants.

The key to the approach is to use three random subsamples of persons

from the foreign-born population (different individuals in each

subsample). The following explanation uses a hypothetical example that

will be carried through for each of the three cards. The hypothetical

example helps explain how an estimate of illegal immigrants is obtained,

once information from all responses is gathered and combined.

Respondents in the first subsample are shown a card with three boxes

such as that shown in figure 5.1. The card in figure 5.1 is in Spanish

because we pretested the three-card method in Spanish. The English

translation is:

• Box A: legal permanent resident (with an official, validly obtained green

card);

• Box B: U.S. citizen; student, work, or tourist visa; undocumented; and

refugee or asylee;

• Box C: some other category, not in Box A or Box B (specify).

Respondents are asked which box applies to them and are told that if it is

Box B, we do not want to know which specific category applies to them.

For respondents who pick Box B, it is the end of the interview. However,

for respondents who pick Box A, a number of follow-up questions are

possible. The purpose of interviews with the first subsample is to obtain a

valid estimate of the percent of foreign-born who have officially obtained

green cards. (Hypothetical example: 35 percent of the resident

foreign-born population have official green cards.)2

2

Respondents who pick Box C are asked what their specific immigration status is. In our preliminary

test, no respondents picked Box C.

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Figure 5.1: Card 1 of the Three-Card Method

B

C

A

PASSPORT

Ciudadano de los 

Estados Unidos

Otra categoria

que no se encuentra en A or B 

(especifique)

Indocumentado

'

Visa de estudiante,

de trabajo, o de turista

RESIDENT ALIEN

U. S. Department of Justice-Immigration and Naturalization Service

SAMPLE

NAME

DOB

ALIEN NUMBER

POE CLASS

052356

A335000000

LOS NPA

Extranjero residente legal 

con cedula de imigracion 

(o como dicen la cedula verde)

permanente obtenida oficialmente

'

'

'

Refugiado o asilado USA

GARCIA-LOPEZ ROSA MARIA

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Respondents in the second subsample (completely different individuals)

are shown a different card (see fig. 5.2). It also has three boxes. The

difference is that Box A shows the status of a (naturalized) U.S. citizen,

whereas Box B includes legal permanent resident (LPR) along with other

immigration statuses. Respondents in this subsample are also asked to

pick the box that applies to them—and told that if it is Box B, we do not

want to know which category applies to them. The purpose of

interviewing this sample with this card is to obtain a valid estimate of the

percentage of the foreign-born who are naturalized citizens. (Hypothetical

example: 30 percent are naturalized citizens.)

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Figure 5.2: Card 2 of the Three-Card Method

B

C

RESIDENT ALIEN

U. S. Department of Justice-Immigration and Naturalization Service

SAMPLE

NAME

DOB

ALIEN NUMBER

POE CLASS

052356

A335000000

LOS NPA

A

PASSPORT

Ciudadano de los Estados Unidos

Otra categoria

que no se encuentra en A or B 

(especifique)

Extranjero residente legal 

con cedula de imigracion 

(o como dicen la cedula verde)

permanente obtenida oficialmente

Indocumentado

'

'

'

Visa de estudiante,

de trabajo, o de turista

Refugiado o asilado

'

USA

GARCIA-LOPEZ ROSA MARIA

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Respondents in the third subsample (again, different persons) are shown

yet another card (see fig. 5.3). It also has three boxes, but this time, Box A

features refugees and persons granted asylum, as well as residents here

legally with temporary visas. Those who pick Box A are asked follow-up

questions to determine their exact legal status. Respondents are told that if

they are in Box B, we do not want to know which specific category applies

to them. The purpose of interviewing this sample is to get estimates of the

percentages in the categories in Box A. (Hypothetical example: 5 percent

are refugees or asylees; an additional 5 percent are here on temporary

visas.)

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Figure 5.3: Card 3 of the Three-Card Method

B

C

A

RESIDENT ALIEN

U. S. Department of Justice-Immigration and Naturalization Service

SAMPLE

NAME

DOB

ALIEN NUMBER

POE CLASS

052356

A335000000

LOS NPA

Indocumentado PASSPORT

Extranjero residente

legal 

con cedula de imigracion 

(o como dicen la cedula verde)

permanente obtenida oficialmente

'

'

'

USA

Visa de estudiante,

de trabajo, o de turista

Ciudadano de los

Estados Unidos

Otra categoria

que no se encuentra en A or B

(especifique)

'

GARCIA-LOPEZ ROSA MARIA

Refugiado o asilado

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Assuming that the categories are mutually exclusive and exhaustive, it is

possible to obtain an estimate of illegals. That is, extending the

hypothetical examples above, we would estimate that 75 percent of the

foreign-born are in the major legal statuses (35% + 30% + 5% + 5% = 75%).3

Suppose also that 1 percent picked Box C (some other category).

Subtracting these hypothetical estimates from 100 percent yields

 100% - 75% - 1% = 24%.

In this hypothetical example, an estimated 24 percent did not claim to be

in any legal status, and the implication is that 24 percent of the

foreign-born population are illegal immigrants.

Preliminary Test of the

Three-Card Method

We conducted a preliminary test of the acceptability of the card shown in

figure 5.1—that is, its acceptability to interviewers and respondents. Our

test population consisted of foreign-born farmworkers, chosen because it

is thought to have a high percentage of illegals and because almost all

speak Spanish. This population also has few naturalized citizens—only

about 3 percent of foreign-born respondents claimed to be naturalized

citizens in the 1994-95 National Agricultural Workers Survey (Mines et al.,

1997). Very few farmworkers are here on legal temporary visas.4

 Nearly

one million farmworkers acquired valid green cards under the IRCA

amnesty of the late 1980s, although many of them have now moved to

other types of work. Thus, we expected that most foreign-born

farmworkers would either be illegals or have valid green cards.

The specific questions for use with the cards and the icons shown on the

cards were developed through a series of pretests that we conducted with

farmworkers and other foreign-born Hispanics. We conducted the pretests

using staff who are fluent in both Spanish and English.

The preliminary test consisted of a contract with the survey firm that

conducts the National Agricultural Workers Survey for the Department of

Labor. Under this contract, 81 interviews featuring the card shown in

figure 5.1 were added to the 1997-98 National Agricultural Workers Survey.

3

As worded in figs. 5.1-5.3, the category for refugees and asylees may overlap with the LPR category. (A

refugee who has attained green-card status may identify as both a refugee and a person with a valid

green card.) Thus, we suggest that in future field tests, the cards be modified, adding the phrase

“without a green card” to the refugee-asylee category.

4

According to our recent report, in fiscal year 1996 only about 15,000 farmworkers were brought into

the United States with H-2A visas for temporary agricultural work, and this represents less than 1

percent of the agricultural field labor force (GAO/HEHS-98-20).

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Each interview was with a foreign-born farmworker.5 All chose to be

interviewed in Spanish. None of those interviewed refused to answer the

question on immigration status, using the card shown in figure 5.1. Of the

81 respondents, 30 picked Box A, claiming to have a valid green card. The

remaining 51 respondents chose Box B, which contains the illegal category

as well as various legal statuses. None chose Box C.

In debriefing sessions, the interviewers told us that overall, the method

was acceptable to them and to respondents. Respondents did not voice

suspicion of the 3-box card. Rather they appeared to accept it at face

value. No special explanations were needed about why we were asking the

questions. Criticisms focused on points such as improving the icons

(symbolic pictures) used on the cards. (More details concerning the

three-card method are included in app. III.)

Possible Use of the Method

in Current Surveys

We also considered how the three-card method might be used with

foreign-born respondents in a more conventional federal household

survey. There are two constraints. First, as currently developed, the

technique is used in a face-to-face personal interviewer survey, rather than

a telephone survey. Second, federal agencies are generally concerned that

the sensitivity of a question on legal status (even using the three-card

method) might affect responses and so would prefer that it be the last

question asked—or that it be used in a linked follow-back survey.6

 The

latter is expensive—costing perhaps as much as $300 per interview,

according to Census staff. Eventually, if the three-card method were

demonstrated to be nonthreatening, it might be possible to incorporate it

as part of a regular federal survey, which would be much less expensive.

However, we believe more testing is needed before the technique is used

in a large-scale survey. Such testing should be done under conditions

similar to those of a federal household survey, and not only farmworkers

should be tested. The tests should further explore the acceptability of the

technique to respondents and should involve cognitive testing to ensure

that questions are worded and the cards are designed for optimal

communication with respondents. There should also be a validity test to

estimate whether, or to what extent, respondents tell the truth when

answering.

5

The contractor did not provide the identities of farm employers to us.

6

A follow-back survey would interview foreign-born respondents identified in a larger federal survey,

such as the CPS or the proposed American Community Survey. The follow-back interviews would be

conducted within a few months of the main survey interview.

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Achieving More Certain

Estimates Through

Evaluative Analyses

Evaluations of the representation of the foreign-born population and key

groups within that population, such as illegals, would allow more

confident (and through adjustments, potentially better) estimates of the

size of the foreign-born population, net change in size, and emigration.

There are a range of possible methods for evaluating data and trends.

Some methods might be costly, while others would be relatively low cost.

• High-cost approaches would involve new data collection. For example, a

survey of self-identified foreign-born workers might be based on a

sampling frame that is independent of the typical census or household

survey approach. That is, it might be possible to draw a sample of work

places and conduct or schedule interviews with foreign-born employees as

they enter or exit those work places. Data on foreign-born persons

interviewed in this way could then be compared to census results.

• A more moderate-cost approach might involve adding a nativity question

to the census short form—but only for households in areas where the Post

Enumeration Survey will be conducted. This would allow separate

estimates of undercoverage for foreign-born and native-born persons

within sex, age, and race (and Hispanic origin) groups. Although no new

interviews would be required, some cost is associated with adding

questions.

• Less costly methods involve no expansion of data collection. For example,

a pilot survey of new green-card holders, sponsored by INS and the

National Institutes of Health, draws its sample from recent INS

administrative records rather than mail lists or neighborhood

enumerations. The pilot survey takes extensive immigration histories, so if

the full survey is implemented on an on-going basis, records for

respondents in the survey could be matched to results of the decennial

census—with a nonmatch indicating a likely lack of coverage. A similar

matching approach might be used for persons new to other legal statuses

(although we recognize that less information would be available on them).

Turning to coverage of illegals, it might be feasible to access records of

interior apprehensions just after the decennial census. Again, records

could be matched to check coverage.

• Another example of a relatively low-cost approach would involve checking

survey claims of U.S. birth against state birth records. The checking might

be limited to a few key states, such as California, New York, Florida, and

Texas. It might be concentrated among (or begin with) respondents

deemed to be at high risk of providing a false answer—perhaps because

they live in areas with a high concentration of foreign-born or even areas

where a high concentration of illegal immigrants seems likely, based, for

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example, on data on all respondents in the area regarding country of

origin, recency of arrival in the United States, and occupation.

• Other low-cost analyses are also possible. For example, the possibility of

underrepresentation of foreign-born respondents because of high

nonresponse rates would be ruled out if response rates separately

calculated for areas with high concentrations of foreign-born were similar

to those for other areas. Alternatively, if response rates are shown to be

different, compensatory adjustments might be used. Other data analyses

could help investigate apparent trends (year-to-year change). These would

include technical analyses such as, for example, checking whether

increases in the number who reported recently arriving correspond to

trends showing increases in the estimated number of foreign-born

residents—and vice versa.

The high- and moderate-cost methods have the advantage of more

generalizable results; for example, they are not limited to persons who

recently received green cards. Some of the less costly methods require

cooperation and data-sharing between, for example, INS and the Bureau of

the Census; but besides lower cost, these have the advantage of allowing

checks on valid reporting of nativity as well as checks for coverage.

Equally important, the data-sharing methods can provide information on

specific legal-status groups.

While we have outlined some of the possible approaches, we realize that

other strategies might also be possible.

Conclusions For informed decisions on immigration issues, policymakers need

information on immigration flow, by legal status. Separate information is

needed on the two different types of flow—new entries into the United

States and transitions to new legal statuses—because, for example,

Congress sets levels of funding for programs to deter illegal immigrants

from coming into the United States and also defines conditions for

allowing illegals to transition to legal status.

Policymakers also need information on the size of the foreign-born

population—again by legal status. And information on emigration helps to

gauge the meaning of statistics on immigration flow and on population

sizes; that is, it balances information on entries with information on exits,

and it indicates the amount of turnover in the resident population.

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and New Strategies

INS records that are maintained for administrative purposes describe the

number of new legal permanent residents (green-card holders), new

refugees and asylees, and new naturalized citizens. As reported in the

Yearbook, however, these statistics are limited by (1) conceptual problems

and confused reporting, (2) undercounts, and (3) information gaps.

• Annual trends in the number of green cards issued—a potentially key

trend in legal immigration flow—is difficult to interpret because of

conceptual problems, and the way it is reported in the Yearbook can

confuse readers. Similarly, invalid comparisons of legal flow to data on

illegals may occur—again because of conceptual problems exacerbated by

confused reporting.

• The number of new asylees is an undercount, because the Yearbook tally

omits certain categories of persons, such as those who are granted asylum

on appeal. The number of persons who newly attained citizenship is also

an undercount.

• Federal statistics are not available for some categories of immigration

flow, such as the number of long-term temporary residents who come to

the United States each year. Perhaps most importantly, there is no

estimate of the total number of foreign-born persons who take up

residence in the United States each year.

Turning to relevant demographic concepts other than flow, statistics are

reported in a more scattered fashion; indeed, a variety of INS and Bureau of

the Census publications, including the INS Web page, must be accessed.

The Bureau of the Census provides information on the size of the resident

foreign-born population, annual net change in size, and emigration.

However, decennial census and survey data on the foreign-born have not

been evaluated with respect to coverage, misreporting of nativity, and

nonresponse. Moreover, there are no separate data for legal permanent

residents, illegal immigrants, or most other statuses. (Neither the

decennial census nor surveys that target the general population ask

questions about foreign-born respondents’ legal status. This is so, in part,

because such questions are very sensitive and might result in problems,

such as distorted answers to the legal-status question or to other items on

the questionnaire.)

The inability to differentiate between key subgroups of the foreign-born

population is important from a policy perspective because virtually all

laws on immigration are based on specific legal statuses. INS has made

efforts to fill gaps for some legal statuses by using the limited data that are

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Improving Information: Current Initiatives

and New Strategies

available and creating assumption-based models. The resulting estimates

are necessarily uncertain because assumptions and judgments are

substituted for data.

We identified or developed strategies that might improve immigration

statistics. Specifically, we devised a new method for collecting survey data

on the legal status of foreign-born respondents. The “three-card method”

asks questions that are less sensitive than a direct question requiring the

respondent to state his or her specific legal status. It ensures absolute

privacy of response and requires no unusual interview procedures. Yet this

method allows statistically unbiased survey estimates for all major legal

statuses. A preliminary qualitative test of the new method indicated that

no one refused to answer the questions. The test population consisted of

farmworkers, and although the test was not designed to make statistical

estimates, farmworkers’ answers were consistent with an interview

population that contains a high proportion of illegal immigrants. Thus, the

new method appears to show promise and to merit further testing and

development.

We also identified strategies for evaluating survey data on the foreignborn. For example, if a household does not respond to a survey, it is not

known whether the residents are foreign-born. Nevertheless, levels of

nonresponse can be compared across communities or areas that are

known to differ in terms of nativity (based on decennial census data or on

the nativity of those who did participate in the survey).

Recommendations To help correct undercounts, eliminate conceptual problems, and where

possible, fill gaps for information on immigration flow, we recommend

that the Commissioner of INS (1) evaluate and, where feasible, improve

data on flow and (2) utilize an effective information typology (either the

one put forward in table 2.1 or an alternative designed by INS) to clearly

distinguish different demographic concepts and to determine which

statistics can fairly be compared to others.

To eliminate confused reporting of data and estimates concerning

immigration flow, we recommend that the Commissioner of INS more

clearly report information about trends in legal immigration flow and

about the difference between the concepts of flow and net change in the

INS Yearbook—or develop a new reporting format that communicates

effectively to policymakers and interested members of the general public.

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Improving Information: Current Initiatives

and New Strategies

To reduce the uncertainty associated with statistical estimates of relevant

demographic concepts other than immigration flow, fill information gaps

for specific legal statuses, and address fragmented reporting, we

recommend that the Commissioner of INS and the Director of the Bureau

of the Census together

• devise a plan of joint research for evaluating the quality of census and

survey data on the foreign-born;

• further develop, test, and evaluate the three-card method that we devised

for surveying the foreign-born about their legal status; and

• either publish a joint report or closely coordinate reports that present

information on population size, net change, and emigration.

Agency Comments INS indicated that it is currently working to improve the clarity of statistical

reporting in the Yearbook and that it finds the typology very useful. INS

also indicated that attempts to fill certain information gaps may be limited

by inherent difficulties and cost considerations. In response to this

concern, we added the phrase “where feasible” to the relevant

recommendation.

With respect to our recommendation concerning the three-card method,

INS made two comments:

• First, INS suggested that because it is not an expert in survey methodology,

its appropriate role would be limited to providing support and

consultation to Census in that agency’s efforts to develop, evaluate, and

test the new method. We believe that, as stated above, the

recommendation for joint INS-Census work allows latitude for INS and

Census to determine their appropriate roles.

• Second, INS indicated that it would need an independent evaluation of the

three-card method before committing funds to the method’s development.

We agree that INS’ obtaining an independent evaluation of the method

before proceeding with further development would be prudent.

The Bureau of the Census provided written comments, which raised no

objections to our findings on data gaps and the quality of federal statistics

on immigration. The Census Bureau also did not object to our

recommendation that Census improve reporting and further evaluate

existing data on the foreign-born.

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Improving Information: Current Initiatives

and New Strategies

However, the Census Bureau stated a concern about its involvement in a

survey designed to obtain information on the legal status of the

foreign-born. Specifically, Census is concerned that even with the privacy

protections of the three-card method, such data collection might

compromise the trust and cooperation of the public. Our recommendation

is only that the Census Bureau be involved in the development, testing,

and evaluation of the new method—not necessarily in any resulting

survey. We believe that Census would bring essential expertise to

designing and overseeing this work. Testing—even large-scale

testing—need not involve data collection by the Census Bureau. We have

not revised our recommendation, but in the interest of clarity, we modified

appendix III to indicate that contractors or other federal agencies might be

used for actual data collection involving the three-card method.7

7

The full text of the Census Bureau’s written response is reproduced in app. IV.

Page 62 GAO/GGD-98-164 Quality of Immigration Statistics
Page 63 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix I 

Experts on Immigration Whom We

Consulted

Experts on

Immigration

Charles B. Keely, Center for Immigration Policy and Refugee Assistance

and Chair, Department of Demography, Georgetown University,

Washington, D.C.

Daniel B. Levine, Westat, Inc., Rockville, Md.

Demetrios G. Papademetriou, Senior Associate and Director, Immigration

Policy Program, Carnegie Endowment for International Peace,

Washington, D.C.

Jeffrey S. Passel, The Urban Institute, Washington, D.C.

Michael S. Teitelbaum, Alfred P. Sloan Foundation, New York, N.Y.1

1

Mr. Teitelbaum was Vice Chair of the President’s Commission on Immigration Reform.

Page 64 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix II 

Demographic Characteristics

This appendix summarizes the available published data on demographic

characteristics of foreign-born persons with respect to current (1996) flow

and “stock”—that is, the size of the total foreign-born population. Major

demographic characteristics include country of origin or birth, age or age

group, sex, race and Hispanic origin, and marital status. Other variables of

interest include area or state of U.S. residence and economic

characteristics such as occupation, employment status, homeownership,

poverty status, benefit receipt, and so forth. Not all demographic and other

characteristics identified above were available for all legal statuses of

foreign-born persons.

Flow of Foreign-Born

Population

This section discusses the available demographic information for

categories of flow for which we were able to identify relevant published

data—legal permanent residents (LPRs), refugees and asylees, and

naturalized citizens (see ch. 3, table 3.1).1

Legal Permanent Residents The 1996 INS Statistical Yearbook reports only one demographic

characteristic separately for new entries, transitions (adjustments),2

 and

combined-flow (total) legal permanent residents: the country of birth.

Other demographic characteristics—age group, sex, marital status, and

state of intended residence—are reported only for combined-flow LPRs,

which totaled 915,900 in fiscal year 1996. For one group of new

LPRs—employment-based principal immigrants—the 1996 INS Yearbook

also reports occupation.3

 Occupational detail is shown for just 261,000 of

the remaining 864,000 LPRs; over 551,000 of these LPRs are students,

children, homemakers, retirees, or unemployed workers.

1

As explained in chapter 3, relevant flow data are not available for (1) foreign students, persons with

temporary work visas, and others admitted temporarily who stay for longer than a year, and (2) illegal

residents, i.e., EWIs and overstays who stay longer than a year. We also were unable to identify

relevant flow data for the total number of foreign-born residents into the United States. Therefore,

demographic characteristics are not discussed for these groups.

2

As noted elsewhere in this report, aliens who transition to LPR status have often already been living in

the United States for years; therefore, the demographic characteristics enumerated should be

understood in that context, rather than interpreted as uniformly applying to the group of aliens newly

arriving in the United States in 1996.

3

Employment-based principal immigrants are persons who qualify for green-card status based on their

labor market skills. Employers wishing to sponsor an alien for permanent residence in order to fill a

job must first apply for labor certification from the Department of Labor. Labor certification is

awarded when there are insufficient numbers of U.S. workers available to undertake the employment

sought by an applicant and when the alien’s employment will not have an adverse effect on the wages

and working conditions of U.S. workers similarly employed.

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Appendix II 

Demographic Characteristics

More detailed tabulations for the 915,900 LPRs can be achieved by

analyzing public use files.4

 Education and income are not included in these

administrative records. When fully implemented, the new green-card

survey (now in pilot stage) should provide a wealth of demographic

information about new LPRs (Jasso et al., 1997). Such information will, no

doubt, prove useful in policy-related analyses, such as assessing potential

labor market impacts.

Refugees and Asylees The 1996 INS Yearbook reports the country of birth for 93,347 newly

admitted refugees and approved asylees in fiscal year 1996. No other

demographic data on refugees or asylees are reported in the 1996 INS

Yearbook, other than for those who became LPRs that year (there is no

requirement for a refugee or asylee to become an LPR). The Department of

Health and Human Services annually reports country of citizenship and

state of initial resettlement (in the United States) for newly admitted

refugees.5

Naturalized Citizens The 1996 INS Yearbook reports the sex, age group, marital status, state of

residence, major occupational group, region, and country of former

allegiance for 1,044,689 aliens who became naturalized citizens in fiscal

year 1996. As noted in chapter 2, these persons were already living in the

United States.

Foreign-Born

Population (“Stock”)

This section discusses the available demographic characteristics for

categories of the resident foreign-born population for which we were able

to identify relevant published data—legal permanent residents, illegal

4

The public use files contain information on aliens granted legal permanent resident status. They are

available on magnetic tapes or cartridges from the National Technical Information Service. These files

contain information on demographic characteristics, which may be broken out separately for new

entries and transitions by the computer-oriented analyst. More information about the public use files,

which are currently available for fiscal years 1972-96, is listed on p. 201 of the 1996 INS Yearbook.

5

The fiscal year 1996 data are reported in “Table 4: Amerasian, Entrant, and Refugee Arrivals by

Country of Citizenship and State of Initial Resettlement” (U.S. Department of Health and Human

Services, 1998, p.A-8). The report also contains certain overall 1996 demographic characteristics (such

as employment rate, labor force participation rate, and unemployment rate, by sex, and English

proficiency, hourly wages, and homeownership at time of arrival). However, these data refer to

refugees age 16 and older in a “five-year sample population consisting of Amerasians, Entrants, and

Refugees of all nationalities who arrived in the years 1991-1996.” Thus, demographic characteristics for

1996 refugees are not reported separately, but the capacity to report them separately may exist,

depending upon the characteristics of the sampling frame and whether the sample of refugees would

be sufficiently large to obtain reliable statistical results.

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Appendix II 

Demographic Characteristics

residents, naturalized citizens, and the total foreign-born (see ch. 4, table

4.1).6

Legal Permanent Residents On its Internet site, the INS reports the estimated state of residence for its

estimated 10,525,000 legal permanent residents (plus or minus 350,000,

and ranges for each state) as of April 1996.7

 No other demographic data

are reported. The state-level distributions of LPRs are based on separate

calculations for each state as follows: (1) adding post-1990 LPRs to the 1990

census count of noncitizens, (2) subtracting 1990 estimates of illegal aliens

and nonimmigrants, (3) subtracting estimates of post-1990 illegal aliens

and nonimmigrants, and (4) adjusting for emigration and mortality. The

ranges are based on adjustments to the 1990 Census. The ranges in the

estimates, INS stated, resulted from adjustments made to the number of

noncitizens counted in the 1990 census.8

Illegal Aliens The 1996 INS Yearbook reports two demographic characteristics—the top

20 countries of origin and the top 20 U.S. states of residence—for 5 million

illegal aliens as of October 1996.9

 No other demographic data are reported.

A separate publication (Warren, 1997) provides estimates for all states

(with upper and lower ranges) and point estimates for 97 countries.

The 1996 state-level distributions of illegals in the 1996 INS Yearbook were

constructed from separate estimates of the distribution of EWIs and

6

As explained in ch. 4, we were unable to identify published statistics on the size of (1) the current

population of refugees and asylees or (2) the current population of foreign students, legal temporary

workers, and others legally here for a temporary period who have stayed longer than a year. We do not

discuss demographic characteristics for these groups.

7

The Internet address is <http://www.ins.usdoj.gov/hqopp/>. Some details of the estimation

procedures are not stated there, however.

8

Specifically, “the census undercount of non-citizens was assumed to range between 5 and 7 percent,

while the percentage of aliens who reported that they were citizens but who were actually non-citizens

was assumed to range between 1 and 5 percent.”

9

The countries are Mexico, El Salvador, Guatemala, Canada, Haiti, Philippines, Honduras, Dominican

Republic, Nicaragua, Poland, Bahamas, Colombia, Ecuador, Trinidad and Tobago, Jamaica, Pakistan,

India, Ireland, Korea, and Peru. The states are California, Texas, New York, Florida, Illinois, New

Jersey, Arizona, Massachusetts, Virginia, Washington, Colorado, Maryland, Michigan, Pennsylvania,

New Mexico, Oregon, Georgia, District of Columbia, Connecticut, and Nevada. The information in the

1996 INS Yearbook is also listed on the INS Internet site at <http://www.ins.usdoj.gov/stats/

illegalalien/index.html>.

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Appendix II 

Demographic Characteristics

overstays.10 For EWIs who entered the United States from 1988 to 1996, the

totals were distributed to states “using INS statistics for the early 1990s on

the destination of the beneficiaries of aliens who legalized” under the

Immigration Reform and Control Act (IRCA) of 1986. Estimates of overstays

who arrived during 1988-96 were distributed to state of residence “based

on annual estimates of overstays by state of destination for 1986 to

1989” (emphasis added). The state-level data for 1996, therefore, reflect

the distributions of illegal immigration for earlier years or legal (rather

than illegal) immigrants and thus may not represent the actual current

distributions.

Naturalized Citizens In the Bureau of the Census Current Population Reports, the

characteristics reported for naturalized citizens include age group, sex,

race, year of entry to the United States, educational attainment, labor force

status, income, receipt of means-tested cash benefits (Aid to Families With

Dependent Children, Supplemental Security Income, and general welfare),

poverty status, and homeownership.

Total Foreign-Born Also in its publication Current Population Reports, Census reports age

group, sex, race, citizenship (naturalized citizen or not a citizen), period of

entry to the United States, educational attainment, labor force status,

income, receipt of means-tested cash benefits (Aid to Families With

Dependent Children, Supplemental Security Income, and general welfare),

poverty status, and homeownership for 24,557,000 foreign-born persons in

1996.11 It reports, for selected states, the percentage of state populations

that were foreign-born.12 It also reports the number and percentage of

foreign-born from selected regions of the world and countries of birth.13

10As explained in ch. 4, these estimates were made by combining estimates of illegal aliens from two

major groups. The first group is aliens who entered surreptitiously across land borders, usually

between official ports of entry, who often are referred to as EWIs (entries without inspection). The

second group is “nonimmigrant overstays”—aliens who were legally admitted to the United States

temporarily and stayed beyond the specified period of admission..

11The Bureau of the Census has placed numerous publications, including those pertaining to the

foreign-born population, on its Internet site at <http://www.census.gov>.

12The states are those with the highest level of concentration: California, New York, Hawaii, Florida,

New Jersey, Nevada, Texas, Arizona, and Rhode Island.

13The regions are Central America, Caribbean, South America, Europe, and Asia. The countries are

Mexico, Canada, El Salvador, Cuba, Dominican Republic, Jamaica, Germany, Great Britain,

Philippines, China, India, Vietnam, and Korea.

Page 68 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix III 

The Three-Card Method

This appendix presents the logic of the three-card method and its roots in

the literature; a summary of the development and initial field test of the

method; the statistical expression of the three-card estimator, together

with its variance and a discussion of the “technique effect” (i.e., variance

costs); and finally, a discussion of how the method might be applied.

Logic of the Method The three-card method involves two processes: First, separate estimates of

each legal status—that is, each status except that of illegal

immigrant—are obtained through subsampling (i.e., by drawing three

random nonoverlapping samples of foreign-born respondents) and asking

each subsample a different legal-status question. Second, an estimate of

the percentage who are here illegally is derived through subtraction.

Specifically,

• As explained in chapter 5, the first subsample of respondents is shown the

3-box card in figure 5.1, which features the status “legal permanent

resident” in Box A. The percent of subsample 1 who choose Box A

represents an estimate of the percentage of the foreign-born population

who are legal permanent residents.

• The second subsample (completely different persons) is shown the 3-box

card in figure 5.2, which features the status “U.S. citizen” in Box A. The

percent of subsample 2 who choose Box A represents an estimate of the

percentage of the foreign-born population who are U.S. citizens.

• The third subsample (again, completely different persons) is shown the

3-box card in figure 5.3, which features two statuses—temporary visas and

refugees or asylees (who have not obtained a green card) in Box A. The

percentage of subsample 3 who choose Box A represents an estimate of

the percentage of the foreign-born who are in these statuses.

• Box C on each card allows an estimate of the percentage who fall into

categories not covered in Boxes A or B.1

No respondent is ever asked about illegal status—nor is any specific

respondent ever identified as illegal. Each respondent is shown one (and

only one) immigration status card, so no one could ever deduce whether a

particular respondent is here illegally. However, an estimate of the

percentage of foreign-born who are here illegally can be obtained by

subtraction, that is, by subtracting from 100 percent each of the estimates

of legal statuses detailed above.

1

We expect that most respondents choosing Box C would be recoded as Box A or B, depending on

their explanation of what their status is. A very small percentage of respondents should fall into

immigration statuses not covered by the categories shown on the cards.

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Appendix III 

The Three-Card Method

While the three-card method is unique, previously reported survey

techniques also involved subsampling. These techniques include

“randomized response” (Warner, 1965; Greenberg et al., 1969; Locander et

al., 1976), “aggregated response” (Boruch and Cecil, 1979), and “item

count” (Droitcour et al., 1991). The stratagem used in the three-card

method of obtaining an estimate of illegals by subtracting estimated legals

from total foreign-born is a “residual method” that derives from

demographic techniques (Schryock, Siegel, and Associates, 1980; Warren

and Passel, 1987).

Depending upon the sample design, the three-card method can be used to

obtain a separate estimate of illegals for a sizable geographic area (such as

California), simply by separately analyzing the data for the area of interest.

This would require the sample design to include enough respondents from

a particular subgroup or geographic area. In this way, estimates could

potentially be obtained for several key states—for example, California,

New York, and Texas—and the main characteristics of the illegal

population could be described. Similarly, a separate estimate of illegals

can be obtained for a particular demographic subgroup (such as women of

child-bearing age or persons below the poverty line).

A unique element of the three-card method consists of a set of follow-up

questions addressed to respondents who choose Box A. These questions

are essential because they can help confirm the validity of answers for

respondents choosing Box A or, alternatively, provide the information

needed to reclassify certain respondents into Box B or C.2

Development and

Initial Field Test

We developed a bilingual (English-Spanish) questionnaire through a series

of pretests and then contracted for an initial, qualitative field test of the

technique. Only one immigration-status card was tested: the card with

“legal permanent resident” in Box A (see fig. 5.1). The field test was

intended to gauge the acceptability of the 3-box card and the question

series to both respondents and interviewers.

2

For example, some subsample 1 respondents who initially choose Box A in fig. 5.2 (U.S. citizenship)

may actually have only applied for U.S. citizenship. By a line of questioning that asks when the

respondent applied for citizenship and whether he or she has as yet actually received a notification

and attended a swearing-in ceremony, those who have only applied for citizenship should be identified.

Such respondents would then be recoded into Box B or C as appropriate.

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Appendix III 

The Three-Card Method

The pretests to develop the three-card survey method were conducted by

four GAO staff who are fluent in Spanish.3

 The pretest respondents

consisted of Hispanic immigrants. GAO staff introduced themselves to

prospective respondents and gained their cooperation at four locations—a

“drop-in” center in Los Angeles; a legal clinic in Arlington, Virginia; and

farms and farm-related facilities in Colorado and Pennsylvania.4

 In all, 27

pretest interviews were conducted by GAO staff.

Throughout the pretests and questionnaire revisions, our aims were to

emphasize respect for the respondent; make sure the respondent

understood the questions; and minimize “question threat.” For example, to

reassure the respondents, just before being shown the immigration status

card, they were told that the topic of the card would be immigration

status. They were also told that the categories were arranged in such a

way that the questions would not zero in on anything they might not want

to tell us.

For respondents who picked Box A (legal permanent resident), follow-up

questions were designed to help us judge the validity of the response. For

example, respondents who picked Box A were asked to state the specific

program through which they obtained their green card. No follow-up

questions were asked of anyone who picked Box B.

We subjected the three-card survey method to a preliminary test of

respondent (and interviewer) acceptance. Specifically, we contracted with

Aguirre International, the survey organization that conducts the

Department of Labor’s (DOL) National Agricultural Workers Survey (NAWS),

to administer our survey in interviews that would be added on to the

regular NAWS data collection effort.5

 A total of 81 interviews were

completed by four interviewers at multiple sites in six states (Arizona,

California, Florida, Georgia, Kentucky, and Texas) between November

1997 and February 1998. Consistent with NAWS procedures, farmworker

respondents were paid $10 cash as an incentive to participate.

Interviewers reported encountering varying degrees of apprehensiveness

on the part of respondents. For example, in Florida, the interviewer’s

impression was that all respondents were illegal, fearful of the

3

Three are bilingual Hispanics; the fourth had lived and worked in Hispanic countries for a total of 5

years.

4

We identified these locations through the help of charitable organizations and health clinics, and by

directly contacting farms in the vicinity of our Denver Field Office.

5

The contractor did not provide the identities of farm employers to GAO.

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The Three-Card Method

Immigration and Naturalization Service (INS), and nervous about the

survey. At some locations, there were instances where respondents voiced

hostility, seemed to identify the survey with INS, or initially mistook the

interviewer for a tax collector. At other locations, respondents appeared

to be relaxed, and some even volunteered to the interviewer that they

were here illegally.

All 81 respondents answered the immigration questions. Interviewers in

Arizona, California, and Kentucky specifically mentioned, in debriefings,

that respondents did not find the 3-box question on legal status too

intrusive.

Of the 81 respondents, 30 selected Box A, that is, claimed to have a valid

green card. Each respondent who selected Box A was able to identify a

specific category or program under which he or she obtained a green card.

Most of these (23 out of 30) said they had obtained their green cards

through the amnesty (Immigration Reform and Control Act/Seasonal

Agricultural Workers) program or through the Family Unity program.

Fifty-one respondents selected Box B, which contained the undocumented

worker category and three other legal immigration categories. Most of

those who selected Box B were probably working without legal

authorization, based on NAWS and our prior work; that is, the population of

foreign-born farmworkers is thought to contain few naturalized U.S.

citizens and very few workers here with temporary work visas.6

The interviewer working in Florida said that some respondents hesitated

to select a box. However, the data indicate that all Florida respondents did

make a selection—and all picked Box B.

No one selected Box C—“Other categories not included in Box A or B.” No

one was coded as “unsure” about which box applied to him or her.

Overall, the general approach—including the 3-box card, the explanation

leading up to the card, and the specific questions asked—appeared to be

acceptable to respondents. However, three issues emerged, as follows:

6

Only about 3 percent of farmworkers claim to be naturalized citizens in National Agricultural Workers

Surveys (Mines et al., 1997). According to a recent GAO report, in fiscal year 1996, only about 15,000

farmworkers entered the country through the H-2A nonimmigrant guestworker program (i.e.,

temporary agricultural work visas); this “represents less than 1 percent of the agricultural field

workforce” (GAO/HEHS-98-20, p. 18).

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The Three-Card Method

• Although most respondents did not appear to be confused about which

box to choose, a few respondents who told interviewers that they had

“fake” green cards or had “border crossing cards” were unsure which box

to pick. There was also one respondent in Arizona who was initially not

sure which of two legal categories applied to him. Interviewers had been

trained to help respondents, when necessary, by restating (paraphrasing)

questions and providing explanations. In the future, to help protect the

privacy of illegal immigrants (by avoiding the need for them to ask a

question that reveals their status), more specific instructions might be

voiced to all respondents at the outset. For example, “Persons with a ’fake’

green card—not a valid one—belong in Box B.”

• Although some respondents in Florida said they found the icons (pictures)

on the cards useful, others voiced criticisms. Interviewers reported that

some respondents thought the icons were childish and unnecessary, and

even that the card was unnecessary because they had understood the

verbal instructions and felt that they did not need help. The California

interviewer indicated that respondents with less education tended to like

the card more than those with more education—perhaps reflecting

reactions to the icons.7

• There were also criticisms of some specific icons: The icon for refugees

shows a person running toward the United States, and some respondents

interpreted the icon as being an undocumented worker running away from

U.S. law enforcement officers. The icon for student, worker, or tourist visa

is a suitcase with various stickers, and some felt that a suitcase was not

clearly linked to an immigration status.

The reactions to the icons suggest there is a need for focus groups or other

qualitative work aimed at evaluating and possibly revising the icons and, if

possible, finding a way to present them that is more acceptable to those

respondents who do not need them.

More generally, as stated in chapter 5, we believe that extensive

testing—including testing to explore the acceptability of the technique to

respondents and to estimate the validity of responses—should be

conducted before the technique is used in a large-scale survey.

7

In addition, one might reason that not all respondents would appreciate the 3-box card. Specifically,

those respondents who do have their green cards would not need the 3-box card; i.e., logically, they

might just as soon answer a direct question. By contrast, illegal immigrants might appreciate the card.

(The Florida interviewer, who said that some respondents found the 3-box card useful, thought that all

respondents there were working illegally; all chose Box B.)

Page 73 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix III 

The Three-Card Method

Statistical Expression

of the Estimator and

Variance

The statistical expression of the three-card estimator of the percent illegal,

its variance, and the “technique effect” are shown in figure III.1. Clearly,

there are variance costs associated with using an indirect method. First,

each estimate of legal status is based on a subsample, rather than the full

sample. Second, the indirect estimate of illegals is affected by the variance

of each of the estimates that is included in its calculation. Assuming that

the three subsamples are of equal size and that for each card 25 percent of

respondents belong in Box A, the confidence interval for a three-card

method estimate of illegals would be three times as large as a

corresponding direct estimate. However, it must be kept in mind that

variance costs depend heavily upon (1) the distribution of immigration

status in the population surveyed and (2) the relative sizes of the three

subsamples. Two examples are presented below to give the reader a flavor

of what “real world” precision might be:

• Example 1: In a population of foreign-born agricultural workers, the

distribution of immigration status might be 55 percent illegal; 36 percent

legal permanent residents; 3 percent U.S. citizens; and 6 percent temporary

workers, refugees, or asylees. Assuming this distribution and a total

sample size of only 1,000, allocated with 100 respondents to answer the

card with U.S. citizen in Box A; 200 to answer the card with temporary

visas, refugees, or asylees in Box A; and 700 to answer the card with legal

permanent resident in Box A, the 95-percent confidence interval for an

estimate of 55 percent illegal would be 49-61 percent.

• Example 2: In the residential foreign-born population of the United States,

taken as a whole, the distribution might be 22 percent illegal; 30 percent

U.S. citizens; 38 percent legal permanent residents; and 10 percent

temporary workers, refugees, or asylees (without green cards). Assuming

this distribution and a total sample size of 13,000—the approximate

number of foreign-born in the March Current Population Survey (CPS)

supplement—with 6,000 respondents allocated to answer the card with

legal permanent resident in Box A; 5,500 allocated to answer the card with

U.S. citizen in Box A; and 1,500 to answer the card with temporary

workers, refugees, or asylees in Box A, the 95-percent confidence interval

would be 20-24 percent.

Page 74 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix III 

The Three-Card Method

Figure III.1: Statistical Expression of

the Three-Card Estimator, Its Variance,

and Technique Effect

We note that in the foregoing examples, the sizes of the three samples

were chosen according to the general statistical principle of “optimal

allocation.”8

 The confidence intervals in the examples would have been

larger if three equal-sized samples had been used.

8

Optimal allocation minimizes the variance of an estimate by assigning a greater proportion of the

sample where the variance is highest—and a smaller proportion where the variance is lowest.

Page 75 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix III 

The Three-Card Method

Possibilities for

Implementation

This section considers possibilities for implementing the three card

method—assuming that further research proves its viability. There are two

key points: First, the three-card method is designed for use in a

face-to-face survey in which the questionnaire is administered by a

professional interviewer. It cannot be used in a telephone survey, because

respondents could not see the cards.9

 Second, because the relevant

population consists of the foreign-born, an appropriate survey to utilize

the method would be either (1) a survey that targets populations with high

concentrations of foreign-born (e.g., NAWS or a survey of a community with

high concentrations of foreign-born) or (2) an ongoing survey conducted

for other purposes that is large enough to include a sizable foreign-born

group.

The CPS is one example of a relatively large survey. The proposed

American Community Survey is much larger. Neither survey conducts all

interviews in person. (The CPS, e.g., repeatedly interviews the same

households, but of eight total interviews, only the first and the fifth are

conducted in person.) A special plan would be required if the three-card

method were to be used with surveys that do not conduct all interviews in

person. Various other federal surveys conducted by agencies other than

Census—or surveys conducted by contractors—might also be considered.

Another issue is that—at least initially—the sponsors of ongoing surveys

would probably deem the three-card method too sensitive to include.

Therefore, one possibility that was suggested in conversations with staff

and officials at the Bureau of the Census is a “follow-back” survey. For

example, a large ongoing survey might be used to identify a sample of

foreign-born respondents who would be “followed back” within, for

example, a few months of the survey interview; a brief reinterview would

then be conducted, including the three-card method.10

It would be more costly to conduct house-to-house canvasing to identify

foreign-born respondents, but the specific costs would depend on the

extent to which canvasing efforts could be targeted, based on existing

census and survey data on the locations where foreign-born persons are

concentrated.

9

It is not known at this time whether the three-card method could be modified for use in a mail survey.

10If such a plan were acceptable to an ongoing survey, the cost might be roughly $300 per completed

follow-back interview. This would put the cost of 12,000 interviews at roughly $3.5 million. Of course,

if the three-card method were eventually accepted as an add-on to the questions asked in an ongoing

survey, the cost per interview would be a small fraction of $300.

Page 76 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix III 

The Three-Card Method

Agency Comments The Census Bureau indicated a concern that appendix III gives an “overly

optimistic evaluation” of the three-card method. To ensure clarity, we

added a sentence to appendix III, which summarizes the caveat stated in

chapter 5—that is, that extensive testing is needed before including the

new method in a large-scale survey.

Page 77 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix IV 

Comments From the Bureau of the Census

Now on p. 69.

Now on p. 56.

Page 78 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix IV 

Comments From the Bureau of the Census

Page 79 GAO/GGD-98-164 Quality of Immigration Statistics
Appendix V 

Major Contributors to This Report

General Government

Division, Washington,

D.C.

Eric M. Larson, Evaluator-in-Charge

Barry Reed, Technical Adviser

Elizabeth W. Scullin, Communications Analyst

Denver Field Office Maria Vargas, Evaluator

Office of the General

Counsel, Washington,

D.C.

Ann H. Finley, Senior Attorney

Office of the Chief

Economist,

Washington, D.C.

Venkareddy Chennareddy, Referencer

We would like to thank Juan Gobel, Los Angeles Field Office, and Nilsa

Perez, General Government Division, for helping with interviews with

Hispanic immigrants.

Page 80 GAO/GGD-98-164 Quality of Immigration Statistics
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