Requiem for the Net Migrant

Despite recent research that has demonstrated the clear superiority of a multiregional perspective in measuring and projecting the dynamics of internal migration flows, many scholars continue to adopt the uniregional perspective that is forced to focus on net migrants, a nonexistent category of individuals. Net migration models are misspecified because the rates that they use confound changing migration propensities with changing population stocks. Moreover, they obscure regularities in age profiles of migration and thereby further misspecify the spatial dynamics generating observed settlement patterns. Thus, the use of the net migration rate as the dependent variable in explanatory models of migration can produce a misspecification of the fundamental relationships that are the subject of inquiry. This paper considers deficiencies of the net migration concept and illustrates them with numerical examples.     

Population Forecasting with Nonstationary Multiregional Growth Matrices

Though the mathematics of multiregional population projections were defined over twenty years ago, and the methodology has seen some adoption internationally, most practitioners in the United States still use rudimentary cohort component projections techniques. Both the stationarity assumption and the implicit five‐year retrospective time scale imposed by the census migration data have probably contributed to the limited use of multiregional projections methods. This paper reviews previous attempts to overcome the stationarity assumption and proposes a decompositional approach using log linear models estimated via the ECM algorithm. The paper discusses the advantages of the decompositional approach and implements the model for intrastate migration in California.     

Population growth and redistribution in Australia: 1911-1966

Concentration and redistribution indices are used to analyze the redistribution of population among the Australian states and territories, between 1911-1966. The relative importance of internal migration in this population redistribution is assessed. It is found that although the pattern of redistribution altered after WWII, the share of land and population held by each state came into closer agreement. Net internal migration was always small in comparison to natural increase and net international migration, but its role in population redistribution was far from insignificant.     

Population growth and redistribution in Australia: 1911–1966

Concentration and redistribution indices are used to analyse the redistribution of population among the Australian states and territories, between 1911 and 1966. The relative importance of internal migration in this population redistribution is assessed. It is found that although the pattern of redistribution altered after the Second World War, the share of land and population held by each state came into closer agreement. Net internal migration was always small in comparison to natural increase and net international migration, but its role in population redistribution was far from insignificant.     

Serial correlation in multiregional migration models

"In this paper, we outline the specification and estimation of a time series of multiregional net-migration equations subject to first-order serial correlation. We show that the necessary nonstochastic adding-up constraint, which requires that net migration in the system sum to zero, imposes restrictions on the serial-correlation coefficients. We estimate equations under these restrictions using data for the ten Canadian provinces for the period 1962-1985. The results confirm the significance of the serial-correlation coefficient and, hence, the importance of incorporating this correction in future time-series models of multiregional migration."     

Requiem for the Fixed-Transition-Probability Migrant

In a recent paper titled “Requiem for the Net Migrant” Andrei Rogers persuasively argues for the use of a multiregional perspective rather than a uniregional one in measuring and projecting the dynamics of internal migration. In particular, he highlights the deficiencies of using net migration rates in population projections, giving illustrations of the very large differences that can occur if constant net migration rates are assumed versus fixed interregional transition probabilities. Net migration rates are conceptually unsound because their denominators are not true “at-risk” populations. Fixed interregional transition probabilities, however, are inconsistent with a sound behavioral representation of migration system dynamics. Whereas such stationary Markov models posit a role for shifting origin region populations, they do not embed the assumptions intrinsic to gravity or opportunity model concepts about the role of changing destination region populations. This paper explores alternative, more behaviorally pleasing interregional models that posit a role for shifting destination populations in altering the attractiveness of migration alternatives. Density-dampened, destination-population-weighted transition probability structures are explored. The importance of modeling intraregional migration separately from nonmovement is stressed.     

TESTING THE SPATIAL SCALE AND THE DYNAMIC STRUCTURE IN REGIONAL MODELS (A CONTRIBUTION TO SPATIAL ECONOMETRIC SPECIFICATION ANALYSIS)*

This article addresses the problem of specification uncertainty in modeling spatial economic theories in stochastic form. It is ascertained that the traditional approach to spatial econometric modeling does not adequately deal with the type and extent of specification uncertainty commonly encountered in spatial economic analyses. Two alternative spatial econometric modeling procedures proposed in the literature are reviewed and shown to be suitable for analyzing systematically two sources of specification uncertainty, viz., the level of aggregation and the spatio-temporal dynamic structure in multiregional econometric models. The usefulness of one of these specification procedures is illustrated by the construction of a simple multiregional model for The Netherlands.     

西安市人口的分布变动研究

基于三次人口普查数据,对西安市80年代以来的人口分布变动进行了系统研究。结果表明:西安市在20世纪80年代便已形成"中心区人口减少、内圈和中圈人口快速增长、外圈人口低速增长"的区域差异格局,90年代这种区域差异格局更明显。通过人口分布模型的回归拟合,尝试性预测了西安市未来人口分布的趋势。结果显示:2010年西安市人口分布的峰值将出现在距市中心约2.5km的城墙与二环线之间。最后探讨了西安市人口分布变动的促进机制。     

基于GIS的中国省际人口迁移流的空间特征分析

文章基于中国第五、六次人口普查与2005年1%人口普查数据资料,采用流数据分析方法,运用GIS空间分析技术,选用省际人口迁移的最大联系线、最大迁出流、最大迁入流、期望线、迁移效率、粗迁移率等方法系统地研究了我国1995-2010年间省际迁移的时空动态特点及其区际联系。结果表明:全国省际人口迁移的流动性不断增强,东部地区更明显;省际最大人口迁出与迁入流反映了中国省际区域间空间相互作用整体框架,全国大致可以分为3个人口吸引片区和5个辐射片区;省际最大净迁移流主要分布在东南沿海地区,中、西部地区分布较少,其空间分布与各省的MEI_(i)指数密切相关。     

Spatial Dimensions of the Easterlin Hypothesis: Fertility Variations in Italy

The paper re–evaluates the Easterlin hypothesis in a multiregional context by conceptually and methodologically accounting for two processes of spatial interdependence in an open subnational demo–economic system: diffusion of fertility norms and values across space, and movements between labor markets. The empirical analysis estimates pooled cross–sectional, time–series models using data for 18 Italian regions from 1952 to 1995. The results suggest that accounting for spatial interdependencies is necessary to avoid model misspecifications. Moreover, the models lead to space–time landscapes of fertility elasticities that suggest, for the majority of space–time units, an inverse Easterlin effect for the diffusion component but support of the Easterlin hypothesis due to labor movements across space.     

Estimating Migration Flows from Birthplace‐Specific Population Stocks of Infants

When adequate data on migration are unavailable, demographers infer such data indirectly, usually by turning to residual methods of estimating net migration. This paper sets out and illustrates an inferential method that uses population totals in the first age group of birthplace‐specific counts of residents in each region of a multiregional system to indirectly infer the entire age schedule of directional age‐specific migration flows. Specifically, it uses an estimate of infant migration that is afforded by a count of infants enumerated in a region other than their region of birth to infer all other age‐specific migration flows. Since infants migrate with their parents, the migration propensities of both are correlated, and the general stability of the age profiles of migration schedules then allows the association to be extended to all other age groups.     

A Hierarchical Migration Model of Population Redistribution within a Central Place Hierarchy

A simple hierarchical migration model is proposed as a mechanism for the redistribution of population within a Christaller central place hierarchy. Given a predefined functional hierarchy, the migration process causes any initial population distribution to converge to an equilibrium distribution. Under certain special conditions, the equilibrium is identical to a central place population distribution derived from economic base concepts.     

Alan Wilson – contributions to research on population and migration

ABSTRACT

This article reviews Alan Wilson's research on population and migration in the 1970s and the 2010s, which supplements his principal contribution - mathematical modelling of urban and regional systems. In the 1970s, drawing on input-output models of economies and working with Philip Rees, Wilson established the accounting basis for Andrei Rogers' multi-regional projection model, adding international migration. Innovative methods were developed to complete demographic accounts, where there were data gaps. In the 2010s, working with Adam Dennett, Wilson systematized methods for estimating migration flows between regions in Europe, employing his family of spatial interaction models. The key aim of both research strands was to ensure that no information was ignored to ensure consistency in population and migration models. The influence of Wilson's contributions to research on population and migration is traced through a survey of subsequent research.     

INTERPRETING SPATIAL ECONOMETRIC ORIGIN‐DESTINATION FLOW MODELS

Spatial interaction or gravity models have been used to model flows that take many forms, for example population migration, commodity flows, traffic flows, all of which reflect movements between origin and destination regions. We focus on how to interpret estimates from spatial autoregressive extensions to the conventional regression‐based gravity models that relax the assumption of independence between flows. These models proposed by LeSage and Pace ( 2008 , 2009 ) define spatial dependence involving flows between regions. We show how to calculate partial derivative expressions for these models that can be used to quantify these various types of effect that arise from changes in the characteristics/explanatory variables of the model.     

中国城市群空间结构演化的影响因素分析——基于铁路客运的功能联系视角

以中国13个城市群为研究对象,采用铁路客运班次构造多中心指数来表征基于功能联系的城市群空间结构,在分析城市群空间结构演变基础上重点分析其影响因素。研究发现,基于功能联系视角的城市群空间结构总体呈单中心化趋势,但地区差异化明显,珠三角、山东半岛和闽东南城市群已表现出多中心化特征;城市群空间结构的多中心程度随经济发展水平的提高表现为先单中心后多中心的演变过程;城市群规模的增大和城市间联系加强促进了城市群向多中心方向演化;而面积小、三产比重高的城市群更有利于形成单中心的结构;政府干预作用对城市群空间结构影响并不显著。鉴于不同城市群空间结构演化趋势不同,未来政策取向应该遵从各个城市群自身规律。     

江苏省流动人口分布的格局演变及其驱动因素——基于城乡建设用地的探讨

基于乡镇单元人口普查数据以及相应年份的城乡建设用地数据,运用空间分析和统计分析方法,尝试分析城镇-农村尺度江苏省流动人口分布格局的时空演变特征,并揭示驱动人口流动的动力机制。结果表明：①规模分布特征是具有较长大值右尾部的正偏分布,总体的集聚趋势增强,城镇和乡村集聚流动人口差距变大;②空间呈现高值集聚特征,热点区主要集中在长江以南的城镇,沿江地区流动人口高密度区域逐渐连绵化;③增长变化呈现长江以北地区城镇的流入人口增加、农村的输出人口减少,以及长江以南地区城镇的流入人口快速增加、农村的流入人口普遍增加的特征;④经济发展水平差异、乡镇企业繁荣、交通可达和政策导向是影响江苏省流动人口集聚的四大动力。     

基于村域微尺度的人口流动类型空间分异及作用机理——以云南玉龙县为例

村域微尺度人口流动过程对县级单元就近城镇化发展、小城镇发展和新型农村社区建设等方面影响凸显.以云南玉龙县为研究区域,以行政村为基本空间单元,深入剖析人口流动村域类型空间分异特征,识别人口流动村域类型空间分异的关键影响因素及其作用机制.研究表明:①玉龙县村域人口流动特征呈现明显的空间分异,具体表现在人口流动强度和人口流动...     

俄罗斯中国新移民现状及其课题研究

1991年以来的俄罗斯中国新移民是一个涉及面广泛的问题, 这一问题的复杂性及其对俄罗斯产生的正负面影响, 在俄罗斯引起了广泛争议。本文分析俄罗斯中国新移民产生的背景、特点及其人口统计学特征, 探讨俄罗斯官方对中国新移民的态度和政策, 概述俄罗斯各方面专家学者对这一问题的研究与看法。作者认为, 要很好地解决这一问题, 需要俄中两国开展明确的具有建设性的合作, 需要一个加强双边关系的更强大的社会平台, 也需要俄罗斯方面实行一种平衡的移民政策。     

Bayesian Model Averaging for Spatial Econometric Models

We extend the literature on Bayesian model comparison for ordinary least-squares regression models to include spatial autoregressive and spatial error models. Our focus is on comparing models that consist of different matrices of explanatory variables. A Markov Chain Monte Carlo model composition methodology labeled MC ³ by Madigan and York is developed for two types of spatial econometric models that are frequently used in the literature. The methodology deals with cases where the number of possible models based on different combinations of candidate explanatory variables is large enough such that calculation of posterior probabilities for all models is difficult or infeasible. Estimates and inferences are produced by averaging over models using the posterior model probabilities as weights, a procedure known as Bayesian model averaging. We illustrate the methods using a spatial econometric model of origin–destination population migration flows between the 48 U.S. states and the District of Columbia during the 1990–2000 period.     

Incorporating the effects of spatial structure in discrete choice models of migration

Discrete-choice theory and logit models are evaluated for their usefulness in analyzing migration patterns in a zonal system. The authors "argue that spatial effects and more specifically the relative location of zones are not taken into account in such analyses. We, therefore, introduce a measure of spatial structure and advocate its usage as a predictor of migration in such models. In an example of intrametropolitan migration in Toronto [Canada], we demonstrate that this variable is not only significant but also it improves the performance of all the other variables with the greatest impact on the distance between zones. In addition, inclusion of this variable improves the overall performance of the model in terms of residuals."