POPULATION DIVISION 

Working Paper #64 

Evaluating Components of International Migration: 

Migration Between Puerto Rico and the United States 

By Matthew Christenson 
Evaluating Components of International Migration:
 

Migration Between Puerto Rico and the United States
 

By Matthew Christenson
 

Synopsis 

On March 1, 2001, the U.S. Census Bureau issued the recommendation of the Executive Steering 

Committee for A.C.E. Policy (ESCAP) that the Census 2000 Redistricting Data not be adjusted 

based on the Accuracy and Coverage Evaluation (A.C.E.). By mid-October 2001, the Census 

Bureau had to recommend whether Census 2000 data should be adjusted for future uses, such as 

the census long form data products, post-censal population estimates, and demographic survey 

controls. In order to inform that decision, the ESCAP requested that further research be 

conducted. 

Between March and September 2001, the Demographic Analysis-Population Estimates (DAPE) 

research project addressed the discrepancy between the demographic analysis data and the 

A.C.E. adjusted estimates of the population. Specifically, the research examined the historical 

levels of the components of population change to address the possibility that the 1990 

Demographic Analysis understated the national population and assessed whether demographic 

analysis had not captured the full population growth between 1990 and 2000. Assumptions 

regarding the components of international migration (specifically, emigration, temporary 

migration, legal migration, and unauthorized migration) contain the largest uncertainty in the 

demographic analysis estimates. Therefore, evaluating the components of international 

migration was a critical activity in the DAPE project. 

This report focuses on the evaluation of the U.S. Census Bureau’s estimate of net migration 

between Puerto Rico and the United States in the 1980s and 1990s. Specifically, the review 

process evaluated and critiqued the previous estimates of net migration from Puerto Rico to the U.S. 

in the 1980s and created an estimate for the 1990s. To produce the estimate of net migration 

from Puerto Rico, the Census Bureau used an adjusted residual survival method. 

Our evaluation resulted in an estimate of net migration between Puerto Rico and the U.S. of 

126,465 in 1980s and 111,336 in 1990s. For both periods, migrants from Puerto Rico were more 

often male than female, were overwhelmingly Hispanic, and would have identified their race as 

being either "white" or "other". In addition, the pattern of the net migration varied by age, with 

flows being generally positive (toward the U.S.) for those below age 40 and negative (away from 

the U.S.) above age 40. Future research will focus on finding and processing administrative 

data that is available in the post-censal period and that will allow the estimation of both in- and 

out-flows of migrants between the U.S. and Puerto Rico. 
Methods 

The previous 1980-90 estimate: These estimates were done in a two-stage process. First, 

passenger traffic data for Puerto Rico were used to obtain an estimate of net international 

migration for Puerto Rico for the period 1980-1990. Subsequently, this estimate was adjusted 

using information on legal permanent international migration of foreign nationals into Puerto 

Rico during 1980-1990. The resultant figure, 288,163, was assumed to represent net migration 

from Puerto Rico to the United States for this period. 

The current approach: During the process of reviewing the methods used to produce estimates 

and projections in the 1990s, it was determined that the passenger traffic data were too unreliable 

to be used for this purpose. In its place, an adjusted residual survival method was adopted and is 

used to the present day. Hence, this method was used by Team 10 to produce the estimates of 

net migration from Puerto Rico to the United States for both the 1980-1990 and 1990-2000 

periods. 

The adjusted residual survival method can be summarized in the following steps: 

1)	 Calculation of annual average net international migration for period (i.e., 1980-1990 or 

1990-2000) by age and sex for Puerto Rico. 

a) The population by sex and 5-year age groups from the census of Puerto Rico in 

the base year (i.e., 1980 or 1990) is entered into the International Programs 

Center's Rural Urban Projection program (RUP). RUP is a population projection 

program that projects each age and sex cohort over time based on the components 

of growth (fertility, mortality, and migration). 

b)	 The base population is survived to the end year (i.e., 1990 or 2000) using vital 

registration data for each year (both births by sex and deaths by age and sex) and 

an assumption of zero net migration. 

c)	 The survived population by single years of age and sex is exported from the RUP 

program. It is then subtracted from the enumerated population in the end year 

(i.e., 1990 or 2000) by single years of age and sex to arrive at a 10-year estimate 

of net international migration for Puerto Rico by single years of age and sex. 

d)	 These totals are divided by 10 to arrive at an estimate of net annual international 

migration from Puerto Rico by age in the end year. Then, the total in each age 

group is moved back 5 years in order to approximate the age at which the 

migrants moved. 

2)	 Adjustment of (1) with estimate of annual average legal migration into Puerto Rico. 

a)	 The number of migrants with intended residence in Puerto Rico by single years of 

age and sex is extracted from the INS micro-data files for each year of the period 

under investigation (i.e., 1980-1990 or 1990-1998) 

Note: 2000 INS micro-data file was not available at the time of this work, so it 

was not considered in the analysis. 

b)	 The panels of data (migrants by age and sex) for the time period under analysis 

are added together and then divided by the number of panels in order to arrive at 

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an estimate of the average annual number of legal migrants moving to Puerto 

Rico in that period. 

c) The results from (b) are added to the results from 1(d) to arrive at the estimate of 

the annual average net migration from Puerto Rico to the United States 

3) Calculate 10-year totals of net migrants from Puerto Rico to the United States. 

a) "Cohortize" the assumed number of net migrants for each year from Puerto Rico 

to the United States in the period under investigation. Specifically, take the 

estimate of the average annual number of net migrants, assume these migrants 

moved in one of the years under investigation (i.e., 1980-1990 or 1990-2000), and 

convert the age of these migrants to the age in the end year (i.e., 1990 or 2000). 

b) Sum the totals by age and sex from (a) This gives the "cohortized" estimate of net 

international migration for Puerto Rico for the 10 year period by age in the target 

year and sex. 

4) Distribution of net migration from Puerto Rico to the United States by race and Hispanic 

Origin. 

a) Use data from 1990 census on US residents in 1990 who lived in Puerto Rico 5 

years earlier by age, sex, race (5 categories), and Hispanic Origin (yes/no) as 

pattern for flow of migrants from the United States to Puerto Rico. 

b) Use data from 1990 census on Puerto Rico residents in 1990 who lived in United 

States 5 years earlier by age and sex as pattern for flow of migrants from Puerto 

Rico to the United States. 

c) Apply race/Hispanic Origin proportions from (a) to (b) to obtain age, sex, race, 

and Hispanic Origin pattern of flow of migrants from Puerto Rico to the United 

States. 

d) Subtract (a) from (c) to get an age, sex, race, and Hispanic Origin pattern of net 

migration from Puerto Rico to the United States. 

e) Apply pattern from (d) to 10-year totals from 3(b) (above) to arrive at the 10-year 

estimate of net migrants from Puerto Rico the United States by age, sex, race, and 

Hispanic Origin. 

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Limits 

Aside from the obvious questions that could be raised about the adequacy of the chosen methods 

to give an accurate estimate of migration between Puerto Rico and the United States, there are 

two limitations of the estimates that deserve mention. 

1)	 The estimation of the number of legal migrants into Puerto Rico ignored the date of entry 

of these migrants and, instead, was based on the date of registration. The drawback of 

this is that the actual year of entry into Puerto Rico was not captured. However, the 

actual difference in the estimated number of net legal migrants into Puerto Rico using the 

two different methods is minimal (approximately 3,000 extra for 1990-2000). In 

addition, we know that there are migrants who moved into Puerto Rico in the late 1990s 

who will subsequently become legal migrants but who are not captured in the data 

because the time series does not extend far enough into the future. Consequently, the 

estimation of migrants for these years is artificially suppressed. Therefore, it was 

concluded that "migrants by date of registration" was an adequate proxy for migrants by 

date of entry for the purposes of this exercise. 

2)	 The assumptions used to distribute migrants by race and Hispanic Origin may be 

inadequate. Particularly, the estimates include an "other race" category that was not used 

in the broader DAPE project. Ultimately, these migrants were simply distributed 

proportionally across the rest of the age, sex, race, and Hispanic Origin groups. 

However, this "other" category contained a large proportion of the overall migrants, so 

this method may have been inadequate. 

Results 

The work of Team 10 resulted in this document, two SAS program files, and two excel 

spreadsheets containing the estimates of migration by age, sex, race, and Hispanic Origin. The 

locations of each of these files are listed below. In addition, Tables A and B give a summary of 

the two sets of estimates: 

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Table A: Net migrants from Puerto Rico to the U.S. by Age and Sex: 1980s and 1990s. 

1980s 1990s 

Age Males Females Males Females 

<1 63 55 46 40 

1-4 1,405 1,203 1,124 998 

5-9 3,229 2,862 3,431 3,250 

10-14 2,894 2,597 4,716 4,512 

15-19 10,670 7,629 10,130 8,221 

20-24 26,954 19,395 21,821 16,841 

25-29 28,200 21,809 25,931 20,208 

30-34 12,254 11,069 16,493 13,322 

35-39 1,455 2,903 5,284 5,095 

40-44 -1,248 941 -245 1,339 

45-49 -2,444 36 -3,330 -1,111 

50-54 -2,632 -391 -5,412 -3,519 

55-59 -3,070 -1,170 -5,798 -4,166 

60-64 -4,211 -2,428 -6,478 -4,587 

65-69 -4,331 -2,541 -6,134 -4,195 

70-74 -2,685 -699 -3,668 -1,983 

75-79 -1,735 -205 -1,322 -259 

80+ -686 -682 201 540 

64,082 62,383 

126,465 

Table B: Net migrants from Puerto Rico to the U.S. by Race and Hispanic Origin: 1980s and 

1990s. 

56,790 54,546 

111,336 

Race 

1980s 

Hispanic Non-Hispanic Total 

1990s 

Hispanic Non-Hispanic Total 

White 

Black 

AIAN 

API 

Other 

50,487 3,358 

5,539 696 

182 31 

462 306 

65,196 208 

53,845 

6,235 

213 

768 

65,404 

42,961 2,392 

4,866 645 

145 38 

385 271 

59,471 162 

45,353 

5,511 

183 

656 

59,633 

Total 121,866 4,599 126,465 107,828 3,508 111,336 

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To summarize these tables, three points stand out: 

•	 The estimates of net migration during both the 1980s (126,465) and 1990s (111,336) are 

substantially below the figure used in the previous demographic analysis for the 1980s 

(288,163). 

•	 The age-sex patterns of the new estimates for both time periods are similar, with 

movement to the U.S. at its height for both sexes at young adult ages (especially 15-39) 

and with return migration to Puerto Rico for both sexes at older ages (especially 50+). 

•	 The race and Hispanic Origin patterns for both time periods are also similar, with the 

great majority of migrants being Hispanic and with migrants primarily identifying 

themselves as "white" or "other." 

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Demographic Analysis–Population Estimates (DAPE) Research Project Reports Related to 

Evaluating Components of International Migration (in order of Working Paper Series Number) 

Deardorff, K. and L. Blumerman. 2001. Evaluating Components of International Migration: 

Estimates of the Foreign-Born Population by Migrant Status: 2000. (Population 

Division Working Paper #58) (December 2001) U.S. Census Bureau. 

Perry, M., B. Van der Vate, L. Auman, and K. Morris. 2001. Evaluating Components of 

International Migration: Legal Migrants. (Population Division Working Paper #59) 

(December 2001) U.S. Census Bureau. 

Cassidy, R. and L. Pearson. 2001. Evaluating Components of International Migration: 

Temporary (Legal) Migrants. (Population Division Working Paper #60) (December 

2001) U.S. Census Bureau. 

Costanzo, J., C. Davis, C. Irazi, D. Goodkind, R. Ramirez. 2001. Evaluating Components of 

International Migration: The Residual Foreign Born. (Population Division Working 

Paper #61) (December 2001) U.S. Census Bureau. 

Mulder, T., B. Guzmán, and A. Brittingham. 2001. Evaluating Components of International 

Migration: Foreign-Born Emigrants. (Population Division Working Paper #62) 

(December 2001) U.S. Census Bureau. 

Gibbs, J., G. Harper, M. Rubin, H. Shin. 2001. Evaluating Components of International 

Migration: Native Emigrants. (Population Division Working Paper #63) (December 

2001) U.S. Census Bureau. 

Christenson, M. 2001. Evaluating Components of International Migration: Migration Between 

Puerto Rico and the United States. (Population Division Working Paper #64) (December 

2001) U.S. Census Bureau. 

Cresce, A., R. Ramirez, and G. Spencer. 2001. Evaluating Components of International 

Migration: Quality of Foreign-Born and Hispanic Population Data. (Population 

Division Working Paper #65) (December 2001) U.S. Census Bureau. 

Malone, N. 2001. Evaluating Components of International Migration: Consistency of 2000 

Nativity Data. (Population Division Working Paper #66) (December 2001) U.S. Census 

Bureau. 

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