David A. Plane

Migration up and down the urban hierarchy and across the life course

In this article, we begin by reviewing the concept of step migration that originated in E. G. Ravensteins seminal papers “The Laws of Migration” (1885, 1889). As a result of the forces of the Industrial Revolution underway in 19th century Great Britain, migrants moved from farms to villages, from villages to towns, from towns to county seats, and thence to large cities. Throughout much of the industrialization era in the United States, net population movements similarly were upward within the urban hierarchy, and step migration today remains widespread throughout much of the still developing world. Our investigations of recent data and trends, however, suggest that the latest U.S. migration-pattern regime is a strongly contrasting one. Many of the major movements in the system of internal (or domestic) migration are flows down the urban hierarchy, although we note highly differentiated patterns for persons and households at specific stages of the life course. We make use of the newly defined metropolitan and micropolitan Core-Based Statistical Areas (CBSAs) and a seven-level size typology to tabulate origin-destination-specific migration flow data from both Census 2000 and IRS tax-return administrative records for the period 1995-2000. We discuss the causes for net movements being either upward or downward in the national urban hierarchy, including the effects of spatially focused immigration, and movement preferences at various ages, including migration in young adulthood associated with entering and leaving college and the military, as well as moves characteristic of the stages of family formation, childrearing, and retirement.

Ties That No Longer Bind? The Patterns and Repercussions of Age-Articulated Migration

Rates of geographical mobility vary greatly, and fairly predictably, across the life course. Our analysis of special county-to-county migration tabulations of Census 2000 data discloses that, when flows are disaggregated by age, radically different patterns of net population redistribution are taking place upward and downward within the national urban hierarchy. The movements at the late-career, empty-nester, and retirement stage are the most “demographically effective” or unidirectional. The elderly fleeing large metropolitan areas have been congregating in micropolitan and rural counties with special climatic and other natural amenities. The opposite net flow is found for younger adults, who have been flocking into megametropolitan conurbations. At the midcareer stage, the net movement is from larger to medium metropolitan areas. We detail the age articulation of county-to-county migration flows with novel graphical portrayals and statistical measures. We give some thoughts on the relationship between intergenerational dependency and migration trends, and we speculate about whether the current patterns of age-articulated movement up and down the urban hierarchy will continue as the baby boom retires and the echo cohorts come of age.

New Directions in Migration Research: Perspectives from Some North American Regional Science Disciplines

This paper takes several surveys of the literature concerning migration research as its starting point and directs the reader toward a number of potentially fruitful lines for future research. Major sections include one on modeling migrant choice in which the pros and cons of using gross versus net migration measures are discussed. A second introduces and discusses the concept of a “spatial” choice set, which has the potential to be implemented with laboratory experimental techniques. The third involves a wide-ranging discussion of new directions in modeling the interrelationships between employment and migration.

MEASURING SPATIAL FOCUSING IN A MIGRATION SYSTEM

Equality indexes used in other geographical contexts may be used to gauge the degree of spatial focusing in an entire migration system or within the gross in- and out-migration fields of specific regions. They provide useful indicators of overall shifts in the patterns of interregional migration and can help give insight into the population redistributive roles played by specific regions. Perhaps the most common equality index used to measure income distribution is the Gini coefficient, yet it appears almost never to have been applied in migration research. In this paper we set forth a variety of Gini indexes to be used for different migration analyses and illustrate their application with recent data on U.S. interstate movements. We argue that the Gini index provides some singularly useful insights that differ from those afforded by other measures more commonly found to date in the migration analyst’ s toolkit.

DYNAMIC FLOW MODELING WITH INTERREGIONAL DEPENDENCY EFFECTS: AN APPLICATION TO STRUCTURAL CHANGE IN THE U.S. MIGRATION SYSTEM

Causative matrix methods can be used to project levels of population change, to monitor changing migration trends, and to aid in forecasting movement during periods of consolidation and dissipation. They are appealing because they provide measures of the changing strengths of all interregional dependency effects. Separate competing destinations and competing origins perspectives on temporal change can be obtained. The column sums and the eigenvalues provide useful aggregate gauges of the relative strengths of regional shifts. Patterns of U.S. interregional migration from 1935 to 1982 are examined using the causative matrix approach. Trends in the gross migration streams underlying the dramatic increase in core-periphery net migration taking place in the 1970s are examined, as is a more recent shift in the major source area of core region net outflow.

Modeling temporal change in flow matrices

Regional analysts are often faced with the task of forecasting future flows. The ability to carry out such a task is often limited to a reliance on either a Markovian assumption or other techniques that use only one or two observed flow matrices. This paper explores alternative methods that may be used to combine the information contained in an observed temporal sequence of flow matrices. Information theoretic principles, lag structures, and constant causative matrix operators are among the techniques discussed. These methods are applied and evaluated using inter-regional migration flow data for the United States.

Recent Migration Patterns in the Developed World: A Clarification of Some Differences between our and NASA's Findings

This paper is a reply to two recently published critiques of our finding of a discontinuity in the recent internal migration patterns of Europe, Japan, and North America. Using data from the HAS A Human Settlements Systems Task, Hall–Hay and Gordon both fail to detect any significant narrowing in the differential between the growth rates of metropolitan areas and the growth rates of rural areas in Europe and Japan over the period 1950–1970 (they concede that this difference has disappeared, and has even been reversed in the United States). Our rejoinder here consists simply of a clarification of our own independent research on regional population change in these same countries. Unlike the IIASA project, this research has been confined, in the case of Europe and Japan, to a study of the trends in net internal migration to their politically and economically dominant core regions, for which data are available for the post-1970 period as well. Most of the disagreement over the presence or absence of a discontinuity in the regional population trends in the countries of western Europe and Japan can be explained by this simple difference in the principal orientations of the two studies, the first towards all metropolitan areas in these countries for the period 1950–1970, and emphasizing the total population growth of these areas, the other towards their densest, richest, and generally most important regions for the longer period 1950–1980, and emphasizing net internal migration to these regions rather than their overall population growth. For there is little doubt, as we demonstrate here, that there has been an abrupt and precipitous reduction in net internal migration towards the core regions of many countries in the developed world in the 1970s, though a comparable reduction may not have taken place to all metropolitan areas in the aggregate. Gordons and Hall–Hays claim to have rebutted our thesis is thus seen to be based on a misconception of the subject of our study.

Migration and the quasi-labor market in Russia

This paper explores the twin concepts of labor demand and labor mobility during the Soviet and post-Soviet periods. The study uses a detailed data set on labor stock, industrial labor demand, and labor flows for the 1980s in the Yaroslavl Oblast, and data on migration and regional labor markets for all Russian regions in the 1990s. Contextual features, such as the social contract, full employment, methods of labor allocation, and a generally low rate of geographic mobility, distinguish the centrally planned quasi-labor market from the labor market in capitalist democracies. The findings suggest that net in-migration induces employment change in the current period rather than in a future period. The job creation effects appear concurrent with migration during the Soviet period. In the post-Soviet period, migration and employment relationships are not predictable based on the same relationships during the Soviet period.

The Wax and Wane of Interstate Migration Patterns in the USA in the 1980s: A Demographic Effectiveness Field Perspective

Demographic effectiveness (or efficiency) is a measure of the unidirectionality of migration to and from geographic areas. This author explores the structure of temporal change in the demographic effectiveness of migration in the United States during the 1980s. The analysis is based on a times series of (51×51) matrices of state-to-state movements derived from matched income tax forms. A number of hypotheses are explored about how in-migration and out-migration fields wax and wane, thereby giving rise to the overall shifts in demographic effectiveness measured over the period. The results highlight the characteristics of recent (1980–88) shifts in US internal migration patterns including net migration reversals from strong net in-migration to strong net out-migration for states with significant energy sectors, the stanching of net out-migration from many states of the American manufacturing belt, the turnaround to net in-migration for all of northern New England, and the continuance of highly effective net in-migration to the sunbelt states of Florida, Arizona, and Nevada.

Estimation of place-to-place migration flows from net migration totals: a minimum information approach.

A truism in demography has been that net migration may be derived from information on gross place-to-place flows, but that gross place-to-place flows cannot be inferred back from information on the net population movements in a system. Some recent work on maximum entropy and minimum information models, however, suggests a possible means for estimating just such a set of place-to-place flows. The net migration constrained model presented here could prove particularly useful for updating detailed migration matrices on the basis of current net migration estimates, and could even provide some clues as to the nature of the still poorly understood relationship between gross and net migration. Performance of the model is demonstrated using flow matrices from the 1960 and 1970 U.S. Censuses of Population.