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Migration and Modernization: The Case of Puerto Rico, 1950-60

Migration and Modernization: The Case of Puerto Rico, 1950-60
Author(s): George C. Myers
Source: Social and Economic Studies, Vol. 16, No. 4 (DECEMBER, 1967), pp. 425-431
Published by: Sir Arthur Lewis Institute of Social and Economic Studies, University of the
West Indies
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Migration and Modernization:
The Case of Puerto Rico, 1950-60
George C. Myers
The role of migration in the process of modernization and regional devel
opment is confounded in the case of Puerto Rico by the fact that both ex
tensive internal and international migration occurred in the post-World
War II era. In this respect, the case shares similar features with many
Western European countries during their heavy period of emigration.1 How
ever, in several important respects the experiences differ: (1) Puerto Rico
holds commonwealth status within the United States and Puerto Ricans, as
citizens, can travel freely between island and mainland; (2) the period of
very widespread movement, 1947-1960, lasted less than 15 years and has
apparently now run its course.2 Most scholars agree that the migration from
Puerto Rico to the mainland of the United States was motivated by the quest
for economic opportunities, not by a desire for a new way of life.3 For many
this meant only a temporary stay in the United States; a conclusion sup
ported by the substantial reverse migration even during years of the heaviest
out flow, and more recently the large return migration to Puerto Rico.4 This
is further facilitated by the inexpensive and rapid air transportation between
the two places. Therefore, it may be more reasonable to discuss all forms of
Puerto Rican migration as essentially "internal migration,'' treating external
migration as one feature of the general process. This report examines sev
eral forms of net migration for the 76 municipios of Puerto Rico between
1950 and 1960.
IB. Thomas, "Long Swings in Internal Migration and Capital Formation," Bulletin of Inter
national Statistical Institute, XL, 1963, pp. 398-412, and D. S. Thomas, Social and Economic
Aspects of Swedish Population Movements, 1750-1933, Macmillan Co., New York, ?941.
2According to published estimates on departures and arrivals in Puerto Rico, the net ex
ternal out-migration declined in 1959 and 1960, and actually recorded a net in-migration in
1961, 1963 and 1965. See: Puerto Rico Planning Board, Statistical Yearbook, Puerto Rico,
Volumes 1-11.
3J. L. Vazquez Calzada, La Emigracion Puertorriquena, Solucion O Problema? Seccion de
Biostadisticas Escuela de Medicina, San Juan, Puerto Rico, August, 1963. The high correlation
between economic conditions in the United States and Puerto Rican emigration has been clearly
established in several investigations.
4 There were 34,040 Puerto Rican natives enumerated in the 1960 census who reported
they resided in the United States in 1955. For an expanded discussion of this issue, see: J.
Hernandez Alvarez, Return Migration in Puerto Rico, Institute of International Studies, Uni
versity of California, Berkeley, 1967. It also should be noted that a total of 55,648
persons residing in Puerto Rico in 1960 were abroad in the United States in 1955.
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Modernization in Puerto Rico, 1950-1960
Puerto Rico in the decade between 1950 and I960 underwent a massive
development that touched upon all aspects of society. In the fields of edu
cation, public health, transportatiqn development and power sources, un
precedented progress was made. While the foundation for these advances
was laid in the previous decade through such programmes as Operation
Bootstrap, the results largely occurred in the 1950-60 period. In 1956 in
come from manufacturing exceeded that from agriculture, marking what
many consider the critical point in the development of a modern society.
The transition also can be examined in demographic terms as well.
The rapid increase in population that characterized Puerto Rico in prior
periods was definitely curtailed in the most recent intercens?l period, 1950
to 1960. From a percentage increase of 18.3 per cent between 1940 and
1950, the population increased by only 6,3 per cent during the ten-year
period 1950 to 1960. While some of this decline can be attributed to re
ductions in fertility levels, the major factor was out-migration from Puerto
Rico. In fact, without these migration losses Puerto Rico's population would
have increased by 27.5 per cent in the ten-year period, and this figure
excludes births that would have occurred to persons if they had not moved,
but remained in Puerto Rico.
While; the aggregate figures for Puerto Rico describe the general sit
uation, it is also necessary to examine the complex redistribution of popu
lation within Puerto Rico itself. Only five municipios put of 77 declined
in population between 1940 and 1950, while over half recorded population
losses during the 1950-1960 period. These losses reflect the important role
that urbanization and migration play in the process of population redistri
bution. In subsequent sections we will examine how these factors were in
strumental in producing variation in population growth. What type of areas
grew the most and which showed the least growth? And what factors were
responsible for municipio change in population?
The transition from an agricultural society to an industrialized modern
society has generally been accompanied by rapid urbanization of the popu
lation. In Puerto Rico this has certainly been true, although some confound
ing issues are introduced. Since rates of natural increase are usually highfer
in rural areas than in urban areas, the growth of urban places depends on
substantial net in-migration. For Puerto Rico the percentage of population
residing in urban places (places with more than 2,500 population)5 increased
from 14.6 per cent in 1899 to 40.5 per cent in 1950. However, the urban
percentage did not increase , at all between 1950 and 1960 and remained
In 1960 a new definition of urban population was introduced that includes
persons residing in urbanized areas around the larger cities as well as per
5The previous definition of urban population used in 1950 d?es n?t include the urbanized
areas of Mayaguez, Ponce, and San Juan, but only their municipal boundaries.
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sons Hying in places of over 2,500 population. Using this current definition,
urban population increased 16.1 per cent in the past intercensal period, and
constituted 44.2 per cent of the total population, while the population in
rural areas declined slightly (.4 per cent). This arises largely from the fact
that urbanized areas are included in this figure; when they are excluded,
the urban population increase was only 6.2 per cent between 1950 and 1960.
A more detailed examination of rural and urban growth by size of place is
provided by Table 1.
TABLE 1. Percentage Change Between 1950 and 1960 in Rural and Urban Places
According to Size in 1960 (Previous urban definition)
Type of Place
Places of
Places of
Places of
Places of
Places of
Places of
Percentage Change
100,000 or more
50,000 - 100,000
25,000 - 50,000
10,000 - 25,000
5,000 - 10,000
2,500 - 5,000
Places of 1,000 - 2,500
Places under 1,000
Other rural territory
Standard Metropolitan Statistical Areas
San Juan
(16.1% Current
- 1.0
- 6.2
- 4.0
Source: U.S. Bureau of the Census, United States Census of Population: I960, Number
habitants', Puerto Rico, 'inal Report PC(1)-53A, Table 3, p. 10.
The urban growth is concentrated primarily in the largest and sm
urban places,, those over 100,000, and below 5,000 population as sh
Table I. The cities with the heaviest losses are found in the 50,000 to
population interval in 1960, while cities over 100,000 show the largest gr
Much of this growth is in the Ponce and San Juan Standard Metrop
Statistical Areas. On the other hand, Mayaguez, a Standard Metrop
Statistical Area of 83,850 persons in 1960, lost population during the
censal period. The rural areas had a similar rate of intercensal growt
pared with the urban areas, using the previous census definition of u
but a slight loss using the current definition. Small rural towns over
lost population, while the very few places under 1,000 show a gain
more populated rural territory registered a gain of 6.7 per cent dur
decade. From these data, it is clear that the trend toward urbaniza
Puerto Rico was attenuated between 1950 and I960. Growth was pri
concentrated in the largest cities, while the intermediate-sized citi
population. The rural areas did not evince rapid growth, either, gai
about the same rate as the urban areas.
The population changes are examined by rural arid urban areas wi
municipios in Table 2. The overall impression is that a high deg
variation in municipio population change was evident for the perio
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TABLE 2. Distribution of Municipios by Change in Population Between 1950 and
1960 and Change in Rural and Urban Per Cent of Total Municipio Population
1950-60. (No change shown where less than . 1 per cent. )
1950-60 Change in Rural and
Urban Percentage of Total
Municipio Population Gain Loss No change Total
Urban gain ? rural gain 10 .... 10
Urban gain ? rural loss 3 8 11
Urban loss ? rural gain 12 7 1 20
Urban loss ? rural loss . . 7 . . 7
No urban change ? rural gain 1 . . . . 1
No urban change ? rural loss 1 1
No 1950 urbana ~- rural gain 6 . . 6
No 1950 urbana - rural loss 3 16 .. 19
No 1950 rural ? urban gain 1 . . 1
Internal and External Migration
According to the theoretical position taken in this paper one of the fea
tures of the modernization process is a complex redistribution of population;
attributable for the most part to migration. Thus, we expect the level of
migration to increase with economic development. In the case of Puerto Rico,
the decade of 1950-60 was marked by extensive movement of the popula
tion. However, the movement was of two types ? internal migration within
the island and external migration from Puerto Rico, mainly to the United
States. Therefore, it is necessary to examine both of these factors in some
detail, to determine how they are related, and to investigate the complex in
terplay of these two forms of migration in the redistribution of population.
One of the serious problems in such research is that data on external migra
tion are seldom available for small areas; nor are they comparable to exist
ing data on internal migration.6 In this report an effort is made to estimate
the extent of these two forms of migration for Puerto Rico during the past
decade by specifically examining net migration patterns for total and in
ternal migration.
On the national level, net migration losses largely nullified the gain from
natural increase; thereby acting as a safety valve for the otherwise imminent
population upsurge. We can also infer that external net out-migration was
largely responsible for the slow-down in urbanization. The large cities were
6The major exception is the study of Sweden by D. S. Thomas, op. cit., where these data
could be obtained.
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clearing houses for the thousands who left Puerto Rico for the United States.
In turn migrants came from less populous urban places and rural areas into
the cities. Although the rural areas typically have higher natural increase
than urban areas, many lost population in the period 1950-60. While it is
not possible, given the existing data, to determine in detail the relative ex
ternal migration losses for rural and urban areas, it is suggested that external
migration drew heavily from rural as well as urban areas. In the former
case, this undoubtedly posed the double attraction for rural inhabitants of
going to the United States directly or going to a city in Puerto Rico. Once
located in a city, the possibility of leaving the island might be yet further
Information on Puerto Rican internal migration can most readily be
obtained from the census item relating present residence to that five years
earlier, which is available for both 1940 and 1960. In addition, special census
tabulations were made on lesidence in 1955 by present place of residence
for those living within Puerto Rico. Thus, it is possible to establish both in
and out- internal migration for each municipio and to derive the internal
net migration rates used in this paper. The proportion of population 5 years
of age and over that reported a move during the five-year period increased
only slightly from 6.8 per cent to 8.3 per cent of the population between the
two periods. Yet during the latter period a much larger amount of external
migration occurred. One can conclude that Puerto Ricans have become much
more mobile over this period; a conclusion no doubt related in part to the
general economic conditions prevailing during the respective periods as well
as the emergent nature of the society.
In order to gain some notion of the extent of external migration for in
dividual municipios between 1950 and 1960, estimates of total net migra
tion were obtained by use of the life table forward survival method. Sur
vival rates based on 1954-56 Life Tables for Puerto Rico were applied to
the 1950 populations of municipios. Although survival values from the mid
dle of the period were utilized, it should be noted that substantial improve
ments in life expectancy were made over this ten-year period. These im
provements probably occurred early in the decade, so that the average
mortality experience thereby underestimates the survival values, and con
sequently understates the net migration. In addition a graduation procedure
by which the five-year age groups were graduated using the formula of
"small extent" was used to reduce distortion in net migration estimates.
The value shown in Table 3 of net external migration derived by the life
table survival method is the uncompensated portion of total net migration
TABLE 3. External Net Migration Estimates, 1950-1960.
Life table survival estimate 420,925
Vital statistics residual estimate 468,746
Net passenger travel estimate 443,357
Source: U.S. Bureau of the Census, United States Census of Population: 1950 and United States
Census of Population: I960. Puerto Rico Planning Board, Statistical Yearbook, 1950 to I960.
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for the island and should be considered as a rough estimate of the net migra
tion for the population 10 years and over in 1960. Although the estimate can
be expected to differ from other estimates since it pertains to a selected
segment of the population exposed to migration and only represents migrants
surviving to the second census date, it seems reasonably comparable to the
estimates obtained by other approaches.
A comparison of the total net migration rates which cover a ten-year
period, and the five-year net internal migration rates yields some pertinent
information about variation among different types of municipios in migra
tion (see Table 4). These rates are based on the appropriate 1960 popu
lations in order to assure some comparability in the rates.7 In the intercensal
period only four municipios (Bayamon, Carolina, Guaynabo, and Trujillo
Alto) showed total net migration gains. Since these areas are all located con
tiguous to San Juan municipio, the gains can largely be attributed to sub
urban movement within the metropolitan area. However, municipios con
taining the largest cities all show total net migration losses and the overall
metropolitan rate is the lowest of the combined rates. In contrast, the rural
and smaller urban categories have the highest net out-migration
TABLE 4. Rates of Internal Net Migration, 1955-60, and Total Net Migration,
1950-60, per 1,000 Population for Combined Municipios,
Puerto Rico (Weighted average rates)
Internal Net
Total Net
Typ? of
Migration Rates
(Five-year period)
Urban to rural
Rural to urban
Small urban
Migration Rates
(Ten-year period)
Large urban
? 7
+ 12
+ 7:
San Juanb
+ 70
Number of
- 59
- 5
a The rural category contains municipios with no urban places (over 2,500 population) in 1950 and
1960. The urban to rural and rural to urban designation describes municipios which lost or gained an
urban place between the two census dates. The large urban category contains municipios with over 50 per
cent urban population or more than 15,000 urban population exclusive of municipios in metropolitan
b The metropolitan area of San Juan determined for this analysis includes Bayamon, Carolina, C
Guaynabo, San Juan, and Trujillo Alto municipios.
Source: U.S. Bureau of the Census, United States Census of Population: 1950 and United
Census of Population: 1960. Also special tabulations of the Puerto Rican Planning Board.
The rates of internal net migration are much lower than correspon
rates for total net migration,8 and in the case of metropolitan areas
are positive. The rural areas and small urban areas show the highest
ternal net out-migration, as was true in the case of tot?l net migratio
the metropolitan areas, San luan had the highest internal in-mieration ra
7It might be noted that the correlations between rates derived with different base p
lations ( average population, etc.) were generally . 99.
8B. Thomas* (op. cit.) also has noted a strong inverse relationship between swings
ternal migration and international migration for countries sending migrants abroad,
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and naturally the largest numerical in-migration as well.
Considering both types of rates, it is clear that there was extensive external
net migration from virtually all the municipios and different types of areas
in Puerto Rico. If we arbitrarily double the internal net migration rates and
take the difference between them and the total net migration rates, it yields
an approximation of external net migration.9 The resulting negative rate
values are very high. Although the highest external out-migration is appar
ently from rural and small urban areas, the external net migration negative
rates in the metropolitan areas are also quite large. Numerically, this means
a substantial portion of the external out-migration was from municipios that
contain the major cities. In short, the net flow of internal migration is from
rural municipios and those that contain smaller cities into the metropolitan,
areas. Although it is risky to speculate on the specific streams of migration
without further information, the results suggest a migration step-flow
phenomenon from rural to small cities and finally to metropolitan areas.
During this period of heavy external out-migration from the island as a
whole, these same areas also experienced substantial external out-migration
A correlation of .70 between the two net migration rates indicates some
correspondence in the patterns of migration, but leaves 50 per cent of the
variance to be explained by other factors.
The highlights that emerge from this research can be summarized as fol
lows: (1) In the decade 1950-60, Puerto Rico made spectacular progress in
social and economic development (2) The increasing.migration of population
was of two kinds, internal and external migration with the latter assum
ing the greater importance. (3) Among the consequences of this external
out-rnigration were the curtailment of substantial population growth for the
island as a whole and the attenuation of the trend toward increased urban
izatipn of the population. (4) Total net migration losses were experienced
by nearly all of the island's municipios, particularly rural municipios and
those containing small urban places. The rates of internal net migration were
negative forcali types of areas except the metropolitan areas. (5) Puerto Rico
appears to have passed from an emigration phase into one in which internal
migration, including inter-urban migration, should assume new importance.
There also is likely to be accelerated growth of urban population. Further
more, the population growth that was controlled in part by external out
migration in the 1950-60 decade may be expected to rise unless further re
ductions in birth rates are established.
?These approximations should be viewed with extreme caution since they assume similar
internal net migration during the first half of the decennial period and they also concern only
the migration?survivors. Th? general tendency would be to underestimate the internal net
migration. Another approach would, be to derive estimated annual proportions of net movers.
For a general discussion of the subject, see H. S. Shryock, Jr., Poptihtion Mobility Within
the Uhit?d States, Community and Family Study Center, University of Chicago, Chicago, 1964,
pp . 25-26. .
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