Rethinking measures of migration: On the decomposition of net migration

The purpose of this paper is to “resurrect” the measure of net migration and defend its continued use under specific research circumstances, despite the current dissatisfaction with the measure as expressed by some scholars. We employ data from the 1980 Census of Population to compare five measures of migration, including net migration rates, in- and out-migration rates, migration efficiency ratios and migration turnover rates. We demonstrate the additivity of in- and out-migration rates with net migration rates and migration turnover rates. Also, we show how the migration efficiency ratio and turnover rates are conceptually and mathematically related. Finally, a simple multivariate model is estimated to show how regression coefficients from in-and out-migration rate models are related to net migration and migration turnover rates.     

Volume,characteristics and consequences of internal migration in Colombia

More than one-third of the Colombian population can be classified as migrants. The prevailing direction of movements is urbanwards, yet it is significant that better than a third of all movements are to rural destinations. Nationwide comparisons of migrants and residents on demographic characteristics would indicate that all streams are selective of the younger and unmarried population, with women predominating in urbanwards movements and men in those to rural areas. However, when compared in terms of socioeconomic characteristics, migrants are more sharply differentiated among themselves than they are from the resident population at each of their respective destinations. Within the migrant population, a natural funneling of the more able migrants to the largest centers suggests itself. Migrants have consistently higher activity rates than the remainder of the population and, in the case of men at least, appear capable of competing for jobs on an equal basis with residents at their respective destinations. Female migrants, however, are consistently overrepresented in lower-status activities, particularly in domestic services.     

Immigration and native migration in New York City, 1985–1990

The 1990 Public Use Micro Sample is used to analyze the relationship between immigration and outmigration of the native born in New York City. The study population is limited to native born males who lived in the five boroughs in 1985. The relationship between immigration and the probability of various kinds of moves is assessed using logistic regression. Results suggest that immigration has an insignificant effect on migratory behavior, with the exception of inter-borough migration. Unlike prior work, this study examines a single metro area, and does not limit itself to inter-state migration. These results are consistent with more recent work (Card 2001; Kritz et al. 2001), which has failed to find a positive labor market level effect of immigration on native migratory behavior. The inter-borough finding is consistent with the occurrence of voluntary residential segregation within the city, in which the native born move away from areas of immigrant concentration but do not leave the labor market, yet there is no direct evidence that this process occurred.     

Effect of census errors on the measurement of net migration

This paper traces the history of the use of vital statistics, survival rates, and ratios in the estimation of net migration from one decade to another. Net migration studies by Hart (1921); Baker (1933) ; Hamilton (1934); Thornthwaite (1934); Lively and Taeuber (1939) ; Henderson (1943); Hamilton and Henderson (1943); Hamilton (1951); Siegel and Hamilton (1952); Lee and Bowles (1954); Price (1955); Lee, Miller, and others (1957); Hamilton (1959); Zachariah (1962); Tarver (1962); Shryock (1964); Eldridge (1965); Hamilton (1965); and the United States Census Bureau are cited as the principal users of various residual methods of estimating net migration. All these demographers have either implicitly or explicitly recognized that errors in census enumeration and in the registration of births and deaths have been reflected in errors of estimated net migration.The underlying characteristic of all the methods used by these demographers has been the estimation of net migration as a residual obtained by subtracting natural increase in an area during a decade from the population change during the same decade. This method has been most generally stated in the classic formula {fx394-1} This formula has been used both with total populations and with aging cohorts. The principal variations of the basic formula have involved the use of life table and census survival ratios as a means of measuring natural increase (B - D), or of estimating "expected" populations assuming no migration. The main points of controversy have involved life table v. censm survival ratios, assumptions regarding the similarity in national and state census enumeration errors, and ways and means of estimating the errors involved in estimates of migration and of migration rates by the various methods.Daniel O. Price (1955) and Zachariah (1962) made important mathematical contributions and attempted to evaluate the errors involved in the me of census survival rates. Eldridge (1965) discovered that, in the United States between 1950 and 1960, the use of the census survival rate method usually gave much lower estimates of net migration than did the classic vital statistic method. Hamilton (1965), using some suggestions by Hope T. Eldridge, developed a mathematical theory or explanation of not only why the CSR estimates were usually lower than the VS estimates but also why the CSR estimates would usually give closer estimates on the true net migration than would the EVS method, which itself is subject to errors of census enumeration and of underregistration of births and deaths. The author also discusses the effect of improvement in census enumeration between 1950 and 1960 on estimates of net migration and derives a generalized formula which takes the timing of migration into consideration.The author acknowledges with sincere appreciation important constructive suggestions made by Dr. Hope T. Eldridge, Population Studies Center, University of Pennsylvania, and the authors of the many papers used as original material. This paper is a revision of a paper read before the annual meeting ot the Population Association of America, Hotel Roosevelt, New York, New York, April 29-30, 1966. Contribution from the Departments of Sociology and Experimental Statistics, North Carolina Agricultural Experiment Station, North Carolina State University. Published with the approval of the Director of Research as Paper No. 2227 of the Journal series.     

Evaluating the relative accuracy and significance of net migration estimates

This paper presents the elements of a theory for evaluating the quality of a set of net migration estimates. The total error in a net migration estimate is decomposed into total bias and total variation. The bias is further decomposed into three bias elements-selection bias, estimator bias, and measurement bias. Tables of bounds for measurement and estimator biases in the vital statistics and the forward survival ratio estimates of net intercensal migration are presented. Both net migration levels and net migration ratios are treated, and provision is made for both life table and census survival ratio estimates. Some of the statistical tables are applied illustratively to net migration data for Canadian counties or census divisions during the 1951-61 decade. Tests of significance and confidence intervals are indicated for net migration estimates, and the basic technical notes are presented in appendices.     

The influence of rural-urban migration on migrants' fertility in Korea,Mexico and Cameroon

The paper presents a comparative analysis of the relationship between rural-urban migration and fertility in Korea, Mexico, and Cameroon. Using an autoregressive model, the results show a significant rural-urban migration adaptation effect in Korea and Mexico, a reduction of 2.57 and 1.45 children during the entire childbearing period, respectively, when compared to a rural stayer, even after the effect of selection has been controlled. Rural-urban migration has a very small impact on fertility in Cameroon. The unexpected result for Cameroon is due to the fact that the fertility-increasing effect of urban residency on the improved supply conditions of births, such as reduced infertility, offsets the fertility-depressing effect of urban residency on the demand for births. As a result of the adaptation to urban fertility norms, the number of country-wide births was reduced significantly in Mexico and Korea over the time periods studied.     

Fertility transition in Communist Albania, 1950-90

In 1945, at the end of the Second World War, Albania had the highest fertility in Europe with an average of more than six live births per woman. However when Albania emerged from behind the 'olive curtain' in 1990, fertility had fallen to three children per woman, despite a pro-natalist environment and in the virtual absence of contraception and abortion. Nevertheless, after five decades, Albania's position at the top of the European fertility league remains unchanged. This paper documents the fertility transition in Albania during the period 1950-90 and places the demographic results in the context of recent socioeconomic and cultural change.     

Associations between overseas,intra-urban and internal migration dynamics in Sydney, 1976–91

Between 1976 and 1991 metropolitan Sydney experienced unprecedented internal migration losses to other states and coastal regions of New South Wales. Levels of overseas immigration were also high and housing costs increased markedly, especially between 1986 and 1991. This paper investigates spatial statistical associations between overseas in-migration rates and internal migration loss within Sydney and between housing costs in Sydney and internal migration outflows. The hypothesis was that housing cost changes and overseas migration contributed additively to migration losses from the metropolis. A complementary analysis of the relationship between migration and housing cost changes is also undertaken. There was a strong positive association between overseas in-migration and intra-urban out-migration and a strong negative spatial association between overseas in-migration and internal out-migration. In consequence, housing cost associations with internal migration loss were found, although not all were in the expected direction. There were stronger associations between housing factors and intra-urban migration. The integration of metropolitan Sydney and Australia into the ‘Pacific rim’ economy is examined with reference to wider explanations of house cost changes and migration flows.     

A study of internal migration in England and Wales

Abstract The main trend in urban/rural migration is a continuous gain, in net terms, of towns from villages and large cities. But this is a result of two distinct migration streams associated with the process of family formation. While before marriage there is positive net migration from villages to both large cities and towns (and from large cities towards towns), after marriage there is a tendency for couples to move towards villages. This is explained by the desire of families, particularly those belonging to the middle class to move out of the urban centres to better accommodation in smaller communities. Considerable variations in migrations within and into regions are observed. These reflect the continuation oflong-term trends in internal migration (as described in Part I of this paper) in particular, population dispersal from Greater London and larger distance migration into the Southern and Eastern regions. Some social characteristics of migrants and non-migrants are compared. Associations between the intensity of internal migration on the one hand, and occupational status, education, social mobility and family size on the other are observed. An attempt is made to assess the extent of migration associated with the marriage process. Although this process increases mobility, its relative contribution to total adult mobility appears to be only slight.     

"Safety" in gay men's personal ads, 1985-1996

A content analysis was conducted of a sample of gay men's personal ads over the period 1985-1996. Ads (591) were analysed, comparing those which contained references to "safety" and those which did not. Approximately 10% of ads included such a reference and this proportion did not change over time. "Safety" was not associated with the personal characteristics of advertisers or their desired partners but was more commonly mentioned by older men. There were strong associations between oral sex, anal sex and mentioning safety. However, the differential risks of HIV transmission associated with oral sex and anal sex were not reflected in the extent of reference to safety, suggesting uncertainty about the risks of HIV transmission associated with oral sex.     

Growth of small and intermediate cities in Korea, 1975-1980

"This paper examines the urban growth of 33 small and intermediate Korean cities during 1975-1980 from the ecological perspective. Using the multiple regression analysis, population growth of a city is measured by variables such as industrial structure, distance from a metropolitan city, and educational level of residents in a corresponding city. At the present development stage in Korea, those cities whose industrial structure is more specialized in the transformative sector rather than other sectors have grown more rapidly. The closeness to a metropolitan city and the educational level of residents for each city strongly influence urban growth of small cities."     

A preliminary analysis of the internal migration of Indonesia]

Like most developing nations, Indonesia is facing a serious population problem. According to statistics, Indonesia has a population of 147,490,298, the fifth largest in the world. The distribution of its population, however, is rather out of balance. For example, the island of Java has an area which constitutes 6.89% of the entire country, but the population of this island is about 61.9% of the country's total. In other areas of the country, population density is low. In the overpopulated areas, there is a surplus of labor. In the areas where the population is scarce, there is a shortage of labor. Because of this situation, the land and natural resources in Indonesia cannot be fully utilized. The Indonesia government is becoming increasingly interested in internal migration in order to solve the population problem and revive the national economy. A series of measures has been taken to redistribute the internal population. First of all, individuals and their families who accept internal migration are entitled to economic benefits in land selection, housing, a food and seed supply, and tax exemptions. With the establishment of migration centers, economic development, expansion of arable land, factories, and construction of roads and development of transportation, the newly developed areas may eventually become administrative units under a province or county. Government offices are being established to handle special problems of migrants. The government is taking care of the migrants' needs in education, medicine and health care, and banking and loans. The measures have been helpful to encourage internal migration and reduce the imbalance of the population distribution, but they have proved to be insufficient. The Indonesian government has realized that birth control is a necessary measure to be taken in order to solve the population problem.     

Social factors as predictors of internal migration patterns in Israel

The influence of 1975 crime and poverty-dependence factor scores on 1976–1980 internal migration rates in Israel was studied. Lag correlations between the two factor scores and in and out migration revealed that poverty-dependence was strongly and negatively related to in-migration and moderately and negatively related to out-migration. No relationship was found between crime and in-migration over the five year period, but a strong positive relationship was indicated between crime and outmigration. It was thus shown that social indicators such as crime and poverty-dependence revealed lasting effects on migration rates, and may be an aid to social planners.     

The contribution of HIV to fertility decline in rural Zimbabwe, 1985-2000

HIV-related sub-fertility has been reported for those populations in sub-Saharan Africa in which contraceptive use is low. We use data from a retrospective survey in rural Zimbabwe and multivariate logistic regression models to show that recent birth rates and current pregnancy rates are also lower among HIV-positive women than among HIV-negative women in those African populations where contraceptive use is high. The fertility reduction is smaller than where contraceptive use is low because age at first sexual intercourse is later and birth rates at older ages are already low. Nevertheless, total fertility is approximately 8.5 per cent lower and HIV-associated sub-fertility may account for as much as one-quarter of fertility decline in Zimbabwe since the late 1980s. Mechanisms for HIV-associated sub-fertility in rural Zimbabwe include more frequent widowhood and divorce, reduced coital frequency, increased amenorrhoea, and possibly, pelvic inflammatory disease. Miscarriage appears to be a less important factor than elsewhere possibly because syphilis is rare.     

The impact of U.S. immigration upon internal migration

The potential adverse effect of immigrants on job opportunities for natives continues to influence debate about immigration policy in the United States. Many studies have examined wage and employment outcomes; by contrast, we examine internal migration. We ask whether or not natives are more likely to depart from or less likely to move to metropolitan areas with high concentrations of immigrants. After controlling for other influences on migration, we find that metropolitan areas with higher concentrations of immigrants have only slightly lower rates of inmigration of natives. Such metropolitan areas also exhibit slightly lower rates of out-migration, contrary to expectation. These results suggest that the effect of immigrants on labor market redistribution of natives is modest.Research reported here was supported by a grant from the Alfred P. Sloan Foundation. We would like to thank Kofi Benefo for helpful comments.     

Comparative empirical evaluations of internal migration models in subnational population projections

While population forecasters place considerable emphasis on the selection of appropriate migration assumptions, surprisingly little attention has been given to the effects on projection outcomes of the way internal migration is handled within population projection models. This paper compares population projections for Australia's states and territories prepared using ten different internal migration models but with identical assumptions for fertility, mortality and international migration and with the internal migration model parameters held constant. It is shown that the choice of migration model generates large differences in total population, geographical distribution and age-sex composition. It is argued that model choice should be guided by balancing model reality with practical utility and model performance is examined against these criteria. Of the ten models evaluated the authors argue that the migration pool, biregional, and biregional with net constraints models offer a good compromise between conceptual rigour and practicality. If the projected origin-destination flows are required then one of the versions of the standard multiregional model with reduced data inputs is preferred. The large variation in projection outputs points to the need for a better understanding of the spatio-temporal structure of migration in Australia.     

Selective migration and health in the USA, 1984-93

Using data from the Panel Study of Income Dynamics, we investigated the impact of health on domestic migration within the USA. We find that, for men below 60 years of age, a move from the middle to the bottom of the health distribution reduces mobility by 32-40 per cent. Non-random attrition from the panel implies that these are lower bounds. By contrast, we find evidence that, among older men, there is higher mobility at the top and bottom of the health distribution than there is in the middle. For women, we find no evidence of a relationship between their own health and mobility, although spouse's health does affect the mobility of married women.     

The impact of immigration on the internal migration of natives and immigrants

In this paper we examine the internal migratory response, by native-born non-Hispanic white men and foreign-born men in the United States, to recent immigration. Our analysis does not support the claim that natives have made a migratory response to recent immigration. Native-born men and foreign-born men were less likely to leave states that received large numbers of immigrants in the 1980s than they were to leave other states, and native-born men had less propensity toward out-migration than did foreign-born men. Out-migration was most likely to be deterred if recent immigrants originated in Europe or Asia. Although native-born non-Hispanic white men showed a tendency toward out-migration if recent immigrants originated in Latin America or the Caribbean, this result was insignificant after we controlled for state economic and regional context.     

Levels and patterns of internal migration in Europe: A cohort perspective

Europe displays important variations in the level of internal migration, with a clear spatial gradient of high mobility in northern and western Europe but lower mobility in the south and east. However, cross-national variation in levels of internal migration remains poorly understood, because it is analysed almost exclusively using cross-sectional data and period measures. This paper seeks to advance understanding of cross-national variation in migration levels in 14 European countries by drawing on a recently proposed suite of migration cohort measures, coupled with internationally comparable retrospective residential histories. It shows that differences in migration levels are mainly attributable to variation in the extent of repeat movement, which is underpinned by the differences in mean ages at first and last move that together delineate the average length of migration careers. Cohort analysis provides a robust foundation for exploring the demographic mechanisms underpinning variation in migration levels across countries and over time.