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."     

The Decentralization Process of Rural Development Policy in Greece

This study aims at critically assessing the decentralization process of rural policy-making and delivery in Greece. Drawing upon a case study of the farm modernization scheme, research findings indicate that despite remarkable decentralization efforts, rural development in Greece seems to maintain its primarily state-emanated design and implementation. Long-standing top-down and sectoral orientation in the formulation of this policy still holds. Apart from the redistribution of responsibilities and the multiplication of competent authorities, a genuine delegation of competencies and resources is needed, coupled with a renewed awareness of integrated policies from the actors involved at all administrative levels.     

DISCRETE SPATIAL CHOICE MODELS FOR AGGREGATE DESTINATIONS*

ABSTRACT. In problems of spatial choice, the choice set is typically more aggregated than the one considered by decision-makers, often because choice data are available only at the aggregate level. These aggregate choice units will exhibit heterogeneity in utility and in size. To be consistent with utility maximization, a choice model must estimate choice probabilities on the basis of the maximum utility within heterogeneous aggregates. The ordinary multinomial logit model applied to aggregate choice units fails this criterion as it is estimated on the basis of average utility. In this paper, we derive and discuss a model which utilizes the theory underlying the nested logit model to estimate the appropriate maximum utilities of aggregates. We also demonstrate that the aggregate alternative error terms are asymptotically Gumbel, thereby relaxing the assumption of extreme value distributed error terms. This is accomplished with help from the asymptotic theory of extremes.     

METROPOLITAN OUTMIGRATION PATTERN OF CANADIAN LABOUR FORCE ENTRANTS, 1971–76

This paper analyses the 1971 -76 metropolitan out-migration pattern of Canadian males in the labour force entrance age group. Migration is conceptualized within a three-level choice framework, and statistical inference is based on a multinomial logit model. It was found (1) that the propensity to outmigrate and the destination choice pattern vary substantially among the 23 metropolitan areas; (2) that 83 per cent of the variation in the destination choice probabilities of metropolitanward migrants can be explained by only five variables (log of distance, cultural dissimilarity, temperature, employment growth, and population size); and (3) that housing conditions are essentially the results (rather than the causes) of intermetropolitan migration .     

THE DEMAND AND SUPPLY OF CHILD CARE: THE CASE OF THE CITY OF WATERLOO, ONTARIO*

The intention of this paper is to stimulate research on the demand and supply of child care services, an issue that has been largely neglected by geographers, although many of the problems involved lend themselves to geographical analysis. In addition, as the female labour force participation rate, the divorce rate, and the incidence of lone-parent families increase, so do the need for and importance of child care. We review the types of child care available in North America and provide statistics to demonstrate that the supply of child care falls short of demand. Furthermore, for the city of Waterloo, Ontario, through the use of 1981 and 1986 Census data we demonstrate that not only is the supply of licensed day care spaces insufficient to meet the demand, but also it is spatially arranged in a suboptimal way. Through population projections and net migration analyses we demonstrate that the demand for child care spaces in the near future is more likely to intensify in the periphery of the city, where the current supply is nonexistent. We thus argue that locational criteria should play a prominent role in the practice of licensing new day care centres. Cet article vise à encourager la recherche sur I'offre et la demande de services de garderie. Ce sujet a été largement négligé par les géographes měme si beaucoup des pro-blèmes rencontrés sont liés à des facteurs géographiques. De plus, la participation des femmes au marché du travail augmentant ainsi que le taux de divorce et le nombre de families monoparentales, les garderies deviennent de plus en plus nécessaires et importantes. Nous passons en revue les différents types de garderies qu'il est possible de trouver en Amérique du Nord et nous présentons des statistiques démontrant que le nombre actuel de garderies ne satisfait pas la demande. D'autre part, à I'aide des données du recensement canadien de 1981 et 1986 pour la ville de Waterloo, Ontario, nous prouvons que non seulement le nombre de places dans les garderies licenciées est insuffisant mais aussi que leur location géographique n'est pas optimale. À I'aide des études sur la population future et la migration nette, nous démontrons que la demande de garderies augmentera vraisemblablement à la périphérie de la ville où les garderies sont actuellement inexistantes. Par conséquent, nous estimons que le critère de localisation doit jouer un rǒle prédominant dans I'octroi des permis d'établissement de nouvelles garderies.     

Regulatory Reform and the Structure of For-Hire Motor Carrier Revenues in Ontario, 1987–1989

Regarding the impact of trucking regulatory reform in Ontario, the overall rate levels for trucking service and rate levels for shipments involving small / remote communities are examined. Analysis indicates that rate levels have not declined in most trucking service sectors. With respect to small / remote communities, the basic question concerns the existence of cross-subsidization, which was found to be present in some industry sectors.     

Population Synthesis: Comparing the Major Techniques Using a Small, Complete Population of Firms

Recently, disaggregate modeling efforts that rely on microdata have received wide attention by scholars and practitioners. Synthetic population techniques have been devised and are used as a viable alternative to the collection of microdata that normally are inaccessible because of confidentiality concerns or incomplete because of high acquisition costs. The two most widely discussed synthetic techniques are the synthetic reconstruction method (IPFSR), which makes use of iterative proportional fitting (IPF) techniques, and the combinatorial optimization (CO) method. Both methods are described in this article and then evaluated in terms of their ability to recreate a known population of firms, using limited data extracted from the parent population of the firms. Testing a synthetic population against a known population is seldom done, because obtaining an entire population usually is too difficult. The case presented here uses a small, complete population of firms for the City of Hamilton, Ontario, for the year 1990; firm attributes compiled are number of employees, 3-digit standard industrial classification, and geographic location. Results are summarized for experiments based upon various combinations of sample size and tabulation detail designed to maximize the accuracy of resulting synthetic populations while holding input data costs to a minimum. The output from both methods indicates that increases in sample size and tabulation detail result in higher quality synthetic populations, although the quality of the generated population is more sensitive to increases in tabular detail. Finally, most tests conducted with the created synthetic populations suggest that the CO method is superior to the IPFSR method.     

Representing the Shape and Orientation of Destinations in Spatial Choice Models

This paper illustrates the importance of spatial unit shape and orientation in spatial choice analysis. It also examines the implications of assuming spatial units to be dimensionless points in this context. Through theory and simulation experiments, it is shown how these aspects cannot be ignored and how the ordinary multinomial logit model applied at the spatially aggregate level is particularly vulnerable to such oversights. The aggregated spatial logit model in the end is recommended as a general formulation which addresses many of these fundamental issues of interest to geographers and regional scientists.     

Effects of residential exposure to steel mills and coking works on birth weight and preterm births among residents of Sydney, Nova Scotia

The Sydney Tar Ponds in Sydney, Nova Scotia, Canada, have been referred to as the most contaminated industrial site in the country. Area residents, aware of the contamination for close to 25 years, are very concerned about their health: past, present and future. In particular, they are concerned about cancer; this is followed closely by reproductive health concerns. The objective of this study was to assess the prevalence and determinants of birth weight and preterm birth among residents living in proximity to an industrial site contaminated with a mix of industrial wastes arising from a former steel mill and coking works (the Tar Ponds) in Sydney, Nova Scotia, Canada. A telephone survey was administered to 500 randomly selected women living in proximity to the site to document reproductive histories. The respondents reported 904 live birth pregnancies occurring in Sydney. The mean birth weight reported for live birth pregnancies was 3,391 g (standard deviation: 570). The reported prevalence of preterm births was 7 percent. Linear regression analyses showed a reduction in birth weight of approximately 85 g among residents in a zone estimated to have higher levels of deposition of airborne effluent from the site. Multivariate logistic regression analyses showed a decrease in the risk of preterm birth as residential distance from the site increased (odds ratio 0.65, 95 percent confidence interval 0.42, 0.98). These data suggest that community exposure to industrial contaminants had some, but little, impact on reported birth weights in this sample of respondents. The apparent increase in risk for preterm births suggests further investigation may be warranted, particularly in light of community concerns. Follow‐up investigations using validated birth records and more sensitive measures of environmental exposure could be used to confirm the findings and further explore the intra‐urban variation in health outcomes. These findings underscore the importance of ongoing clean‐up efforts in Sydney.     

Rent control measures of immediate post‐war period (1944–1952) and their impact on urban development in Greater Athens

The purpose of this paper is first to highlight the importance of the immediate post‐war period in influencing development trends and spatial policy in post‐war urban Greece and Athens in particular. Second in this respect, to stress on the critical impact of rent control measures adopted in response to specific social economic and political issues which emerged at the time. Rent control—together with other exceptional reconstruction measures—contributed above all to the reinforcement of the post‐war development pattern, founded on owner occupation and self‐financed Property development. This in the short run acted against a planned policy rationale and to the various planned attempts formulated during reconstruction. In the long run, it has also acted as a determinant for the consolidation of an ‘non‐planning policy’ situation persistent in Athens and in most urban areas in Greece.