Evaluating Components of International Migration:
Migration Between Puerto Rico and the United States
By Matthew Christenson
U. S. Bureau of the Census
Washington, D.C. 20233
Working Paper Series No. 64
This paper reports the results of research and analysis undertaken by
Census Bureau Staff. It has undergone a more limited review than
official Census Bureau publications. This report is released to inform
interested parties of research and to encourage discussion.
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
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.
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
Calculation of annual average net international migration for
period (i.e., 1980-1990 or 1990-2000) by age and sex for Puerto
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
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.
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.
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
Adjustment of (1) with estimate of annual average legal migration
into Puerto Rico.
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
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 an estimate
of the average annual number of legal migrants moving to
Puerto Rico in that period.
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
Calculate 10-year totals of net migrants from Puerto Rico to
the United States.
"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).
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.
Distribution of net migration from Puerto Rico to the United
States by race and Hispanic Origin.
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.
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
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.
Subtract (a) from (c) to get an age, sex, race, and Hispanic
Origin pattern of net migration from Puerto Rico
to the United States.
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
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.
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.
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.
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:
Table A: Net migrants from Puerto Rico to the U.S. by Age and Sex:
1980s and 1990s.
Table B: Net migrants from Puerto Rico to the U.S. by Race and Hispanic
Origin: 1980s and 1990s.
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
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"
Demographic Analysis-Population Estimates
(DAPE) Research Project Reports Related to Evaluating Components of
International Migration (in order of Working Paper Series
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
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.
Source: U.S. Census Bureau, Population Division,
Population Studies Branch
Author: Matthew Christenson Questions? / 1-866-758-1060
Created: June 27, 2002
Last Revised: October 31, 2011 at 10:03:11 PM