Factors affecting regional differences in population growth in the United States are explored. "In this study, we estimated the contributions of births, deaths, and migration to changes in population size between 1950 and 1980 for the 48 contiguous states in the United States. We found that population momentum (i.e., the growth that would occur in a closed population if fertility and mortality rates remained constant) had the largest effect on population growth in most states, but that differences in net migration were the major cause of state-to-state differences in growth rates. We also found that net migration has been gaining in importance compared to natural increase as a component of population growth. We expect this trend to continue in coming decades." This is a revised version of a paper originally presented at the 1988 Annual Meeting of the Population Association of America (see Population Index, Vol. 54, No. 3, Fall 1988, p. 429).
"A model of private local labor demand and interjurisdictional migration is presented and estimated using data from Swedish counties and municipalities for 1979-84. Our goal is to compare the effects on local labor markets of distinctive public-sector programs with those of traditional market variables. We find that local income taxes and tax-equalization grants have important effects on local labor markets; regional development policy measures and geographical-mobility subsidies do not. Thus, recent efforts scaling back some of these programs may not materially alter the regional economy's performance. Wages and other traditional market variables are also often found to influence significantly local labor markets."
"Regional scientists remain interested in studying interregional differences in the growth rates of population and employment. Following the earlier work of Carlino and Mills, this paper examines growth trends at the county level in the U.S. during the period 1981-1989. Five major sectors of employment are examined. A partial adjustment model is developed that captures intercounty differences in amenities, business and fiscal conditions, demography, employment structure, and relative location. Some evidence is given that population and employment growth was simultaneous, although feedback effects apparently were not strong."
The Beckmann and McPherson model systematically formulates city sizes according to the central place principles of Christaller with the tenets of economic base theory. This paper continues the analysis of this hierarchical model by exploring some of its more implicit properties. -from Author
A nonlinear model of population migration is presented in order to provide a dynamic explanation for the formation of metropolitan areas. "In Section 2 the model is introduced in terms of the rate equations for the mean values of the regional population numbers with specifically chosen individual transition rates. Section 3 gives a survey of concepts and results for the convenience of the reader not interested in the details of the mathematical derivations. Section 4 derives the stationary solutions of the rate equations, that is, the equilibria of the system. Section 5 treats the time dependent solutions of the model equations focussing on the exact analytic solutions along so-called symmetry paths. Section 6 analyzes the dynamic stability of the symmetry path solutions and decides which stationary states are unstable and which are stable equilibrium states."
The persistence of HIV/AIDS has seen a revival of academic interest in the development of modeling systems to assist understanding the population dynamics of this infection. Moreover, it has become increasingly recognized that a key component of these systems for interpreting disease prevention is their reproduction rate, which provides an indication of whether an epidemic might start in a community described by a particular set of epidemiological characteristics. The properties of these rates have been explored in detail for models of a single risk behavior but not for multiregion formats that allow for the transfer of infection between geographical units. Therefore, in this paper the author derives reproduction rates for a multiregion HIV/AIDS model together with their associated critical thresholds that estimate the minimum population of susceptibles necessary for an epidemic to begin. These statistics are interpreted for a simplified global setting representing regional variations in the potential onset of HIV/AIDS. In the discussion the author examines the potential applicability of these results to understanding HIV/AIDS prevention.
Specifies a general functional form suggested by Zarembka (1974) for the study of interstate migration in USA and uses the maximum likelihood method suggested by Box and Cox (1964) to estimate the parameters in the general form. The empirical results obtained from alternative functional forms are presented and compared. The validity of linear and log-linear specifications are examined along with other functional forms commonly used in econometric studies. A general functional form and the estimation procedures are introduced. -Authors
"The paper is devoted to modeling the relationship between the density of service centers and the density of population (or...the density of demand). Several models lead to an exponential function with the exponent equal to [two-thirds]. For a number of real systems of centers, the power is considerably different from [two-thirds] (more often it is nearer to 1). I describe a series of models that explain this difference." The application of the model to U.S. data is discussed.
"The role of location-specific amenities in human migration decisions, and subsequently regional development, is explored. A framework is developed which motivates a new assessment of existing alternative models of regional development, indicating the need for additional modeling efforts which focus upon amenities as critical elements in such analyses. The approach hinges upon the notion that amenity values are capitalized into wages, rents, or other local prices. This process of capitalization enables researchers to explore the implicit value that society places upon amenities, which can then be used in assessing future regional-development trends in a more comprehensive manner."
PIP
An attempt is made to analyze the phenomenon of migration using rent as the single variable that could serve as a proxy for the many amenities that might affect migration patterns. A theoretical treatment of the implications of rent capitalization for migration is first outlined. Empirical results indicating the usefulness of this approach are then presented. The geographic focus of the study is on the United States.
"In this brief study, I ask the most elementary question about the coherence of [U.S.] central cities and suburbs: are their population changes correlated in any simple way?...Specifically, I ask the following question: suppose one knows the national population growth rate, whether an SMSA component is the central city (cities) or suburbs, and the region in which the SMSA is located, then would the ability to explain the component's population growth rate be improved by knowing which SMSA the component is in?... The conclusion is that there appears to be an SMSA effect on population growth."
In recent articles Evans (1990) and Harrigan and McGregor (1993) (hereafter HM) scrutinized the equilibrium model of migration presented in a 1989 paper by Schachter and Althaus. This model used standard microeconomics to analyze gross interregional migration flows based on the assumption that gross flows are in approximate equilibrium. HM criticized the model as theoretically untenable, while Evans summoned empirical as well as theoretical objections. HM claimed that equilibrium of gross migration flows could be ruled out on theoretical grounds. They argued that the absence of net migration requires that either all regions have equal populations or that unsustainable regional migration propensities must obtain. In fact some moves are inter- and other are intraregional. It does not follow, however, that the number of interregional migrants will be larger for the more populous region. Alternatively, a country could be divided into a large number of small regions that have equal populations. With uniform propensities to move, each of these analytical regions would experience in equilibrium zero net migration. Hence, the condition that net migration equal zero is entirely consistent with unequal distributions of population across regions. The criticisms of Evans were based both on flawed reasoning and on misinterpretation of the results of a number of econometric studies. His reasoning assumed that the existence of demand shifts as found by Goldfarb and Yezer (1987) and Topel (1986) invalidated the equilibrium model. The equilibrium never really obtains exactly, but economic modeling of migration properly begins with a simple equilibrium model of the system. A careful reading of the papers Evans cited in support of his position showed that in fact they affirmed rather than denied the appropriateness of equilibrium modeling. Zero net migration together with nonzero gross migration are not theoretically incompatible with regional heterogeneity of population, wages, or amenities.
"This paper questions the plausibility of the assumption of interregional equilibrium in recent research into migration and the valuation of amenities in the United States. It is shown that it is difficult to develop a satisfactory explanation for continuing net migration which is compatible with the equilibrium assumption, and that recent relevant research generally fails to support the idea that the U.S. economy is in equilibrium. The association of higher rent levels with in-migration is explained as a short-run phenomenon. If the spatial economy is in disequilibrium, then the valuations of amenities assuming equilibrium will be biased, being probably too low in areas of net in-migration and too high in areas of net out-migration."
The question of regional differentiation is analyzed in terms of a population of individuals, characterized by a frequency distribution of risk averseness, inhabiting two stochastically distinct regions. The principal question posed in the analysis concerns conditions under which significant differences occur between the distributions of risk averseness in the two regional populations. The equilibrium distribution of preferences for risk bearing in either region depends on the initial regional distribution of such preferences and on the level of transport costs. There is still, however, a simple partition in terms of risk averseness between those who do and those who do not migrate from a given region.-from Author
"This study examines the effect of information and psychic costs on the remigration propensity of the U.S. labor force. Specifically, the study investigates how the proximity of a potential migration destination to a previous residence, and familiarity with this residence, affect information and psychic costs, and thus, remigration propensity. In this respect it is hypothesized that familiarity with, and location of, a prior residence are significant determinants of both the migration destination and the allocative efficiency of the remigration process." Several specific hypotheses are developed and tested using data on interstate, nonreturn, repeat migration of the white male labor force over the period 1965-1970.
"By ignoring individual unemployment compensation benefits and conditions of job termination, past migration research has concluded that personal unemployment doubles the likelihood of interstate labor-force migration. Findings from the present study indicate that aggregating the unemployed, without adjusting for these two factors, overstates the probability of migration for the involuntarily unemployed benefit recipient and understates the likelihood of migration for the voluntarily unemployed benefit recipient. The results suggest that federal discretionary unemployment-compensation programs, which are implemented during recessionary periods, likely serve to retard out-migration of those who are involuntarily unemployed." Data are from a 1982 sample of unemployed U.S. workers.
PIP
The authors investigate an agriculturally based policy for improving rural incomes and for retarding the rural-urban migration flow. The production of agricultural goods is characterized by a production function in which output increases with increases in agricultural labor inputs, capital, public infrastructure, land, and technology. Differences among regions in agricultural technology will reflect regional differences in education, the institutionalized form of productive organization, and differences in access to technological information channeled through more technically advanced cities. To pick up the effect of out-migration changes in state agricultural labor supply and upon agricultural output, the state's agricultural out-migration rate is included together with the agricultural labor force. The gross migrant flow between 2 locations is hypothesized to depend upon a set of variables influencing the individual's perception of the economic rate of return to be gained by moving, a set of variables reflecting the individual's propensity to relocate, the labor displacement effects of investments, and the at risk population at 1 location available to migrate. It is also taken into account that individuals differ in their response to information about origin and destination wage differentials and that individuals may or may not perceive a new ecnomic gain from migration but may base the decision on other considerations. Results of a statistical analysis using data from the Mexican census of population for 1960 and 1970 are: 1) size of the rural labor force was negatively associated with agricultural wages, contrary to expectations; 2) small farmers have benefited from the expansion of irrigation in Mexico; and 3) higher urban wages attract migration, and higher growth rate of agricultural income retards rural-urban migration. With respect to the 1950-60 decade both agricultural income and rural out-migration impacts could have been substantial but both the impact on local urban growth and on the rate of in-migration to the primate city would have been slight.
"The primary objective of this paper is to investigate procedures for detecting and handling existing border biasing in spatial statistical analysis." Six conventional solutions to the boundary value problem are criticized, and three alternate statistical solutions are proposed.
"The purpose of this study is to construct a dynamic model of migration in Great Britain based on time-series data developed from the records of the National Health Service Center Register (NHSCR) on male migrants of working age between 1975 quarter 2 and 1979 quarter 2." A two-stage methodology "was developed...which differed in many important respects from the techniques adopted in previous studies of time-series migration flows. Regional push and pull factors were derived on the basis of the revealed preferences of migrants, using a two-stream gravity model, and then subsequently related to vectors of regional characteristics, within a general dynamic setting. Factors affecting the overall volume of migration nationally were separated out from those determining the internal direction of migration flows, and factors affecting distance sensitivity. Despite weaknesses in the available data set, the results achieved...suggested many interesting dynamic responses, implying lengthy and important lags in the estimated relationships."
"An empirical test of the effects of exogenous shocks upon a region's population size is conducted in the framework of an equilibrium locational model. The model emphasizes the separation of endogenous from exogenous factors, a point omitted in most empirical studies of aggregate migration. Exogenous changes are manifested in the local relative cost of living and the local relative unemployment rate. Hypotheses are tested using a national sample of youth, in addition to census, data [for the United States]. Surprisingly, a simple measure of the size of shock to a regional economy has the greatest explanatory power compared to more sophisticated measures based on prior business cycles."
"This paper examines the role of the migration mechanism in the context of a general interregional factor flow adjustment model. Using an estimation technique, which pools cross-section and time series data, the direct effects of migration flows and regional investment on the growth of regional wages and unemployment [in Canada] are examined. The results suggest that migration has a small, but significant impact on regional wages and unemployment rates."
"This paper explores theories of population growth, and implied economic growth, among the major U.S. metro areas and regions. One set of theoretical arguments [favors] the growth of large cities, while an alternative set of arguments [favors] the growth of the smaller urban areas. Still another set of arguments [combines] economic space and urban size in the concept of regional growth centers as the engines of regional growth. Granger causality tests are applied to determine the role of urban size or growth centers as engines of regional growth. The test results indicate no causal relationship exists."
The paper analyzes the spatial dynamics of a class of systems in which many agents continually reassess decisions of where to locate in a given region. Each agent gives rise to an externality whose impace diffuses to other agents. Thus every agent experiences a composite of externalities emitted by other agents. This composite is termed a spatial externality. On the one hand, the level of the externality at any location depends on the spatial distribution of the population. On the other hand, the distribution of the externality induces changes in the distribution of the population. It proves of interest to analyze this joint unfolding of a population distribution and an externality distribution, particularly for the case of several classes on interacting agents.-Authors
"Using the basic summary of urban structure given by the population density function, this paper estimates changes which have occurred in the structure of the Detroit [Michigan] metropolitan area during the past two decades. Both overall density changes and direction-specific changes are estimated using census data and the method of cubic spline regression. The results give more revealing insight into the structural changes which have occurred in the city than has been possible with traditional models of urban population density."
