ALTERNATIVE MODELS FOR ORGANIZATION OF STATE COURT SYSTEMS*

The dominant theme in court reorganization has been to state judiciaries by consolidating trial courts and centralizing their administration in a state level office. This article suggests that the debate over the relative merits of a centralized vs. a decentralized (or fragmented) court system ignores the rich variety of organizational structures used in other fields. The potential judicial implications of three models-franchise, corporate, and federal-are examined in detail. Their underlying assumptions are compared with those of the centralization approach. The argument is made that none of the models is appropriate for all circumstances. Each approach to court organization emphasizes a particular set of objectives at the expense of another set. An effort is made to identify what each approach has to offer.     

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.     

ADDITIVE-INTERACTION MODELS OF SPATIAL AGGLOMERATION*

A wide variety of existing models of spatial agglomeration postulate additive-interaction effects among agents. In this paper, a synthesis of such models is achieved by establishing certain mathematical equivalences between them. In particular, it is shown that Rockafellar's conjugacy theory of concave functions yields a symmetric one-to-one correspondence between three classes of existing models, here designated as spatial-accessibility models, endogenous-contact models, and fixed-contact models. These correspondences not only allow the transference of results between models, but also suggest new economic interpretations of each model in terms of its conjugate model. A series of examples are drawn from the literature to illustrate these results.     

ELASTICITIES OF CONSTRAINED GRAVITY MODELS*

ABSTRACT Doubly constrained gravity models require a balancing procedure to make estimated origin and destination totals consistent. We show through a series of examples that not just the magnitudes but even the signs of derivatives and elasticities of gravity model flows depend on the specific balancing procedure used. Hence, if such elasticities are regarded as meaningful, then the balancing of origin and destination totals must be regarded as an integral part of the gravity theory itself.     

POISSON GRAVITY MODELS OF SPATIAL FLOWS*

ABSTRACT The purpose of this paper is to bring together a number of results on spatial flow models, and to reformulate them within a unified probability framework based on Poisson frequencies. To do so, a class of discrete stochastic processes, designated as independent flow processes, is developed which not only yields a complete characterization of Poisson flow frequencies, but also allows a wide range of gravity-type flow models to be formulated within this distributional framework. In particular, a hierarchical classification of 12 model types is developed, and each model type is shown to be characterizable directly in terms of behavioral axioms on independent flow processes.     

THE ECONOMICS OF AIR TRAVEL GRAVITY MODELS*

Starting with the aggregate demand model of economics, a model of demand for intercity air travel is developed which contains the gravity model as a less general submodel. The more general model is referred to as the alternative opportunities model since it takes account of alternative destinations open to travelers, not just origin and destination as does the gravity model. The demand model approach has the virtue of providing a theoretical basis for understanding and analyzing the gravity model. The gains from treating alternative locations and demand motivation variables are a substantial increase in explanatory power over that yielded by the gravity model, the identification of statistically significant determinants of air travel, and better measurement of the coefficients of population and distance by taking account of these other variables and somewhat better forecasts. A shortcoming of procedures used here is aggregation of air trips with different purposes and thus lack of clear specification of the size of effects of different variables on different types of travel. Overcoming this difficulty must await origin-destination data listed by trip purpose.     

TESTING CRITERIA FOR DETERMINING LEADING REGIONS IN WAGE TRANSMISSION MODELS*

In this study, we use a vector autoregressive modeling framework to test the zero restrictions implied by alternative criteria for ranking regions into hierarchies in the wage-transmission debate. This approach allows formal statistical tests to be carried out for competing criteria suggested for determining leading and following regions. The ability of the modeling technique proposed here to produce a set of nested hypothesis tests of alternative criteria is in stark contrast to the historical literature in this debate. Researchers have traditionally proposed a criterion for ranking regions into a hierarchy, and then argued for the merits of their particular criterion by demonstrating that an econometric model of wage formation produces statistically significant coefficient estimates when their criterion is used to rank the regions of their data sample. We apply the methods proposed here to a sample of eight midwestern cities in the U.S. in order to test the following criteria: Beaumont (1983), Hart and MacKay (1977), Reed and Hutchinson (1976), unemployment rate, and earnings level. The test is for consistency with the Granger-causal structure of wage interactions inherent in the wage diffusion idea. We argue that the technique set forth here is a real step forward that should allow a resolution of this particular debate. The proposed procedures might also be applied to empirically test other regional science hypotheses concerning for example, intercity and interindustry causal structures.     

STATISTICAL PROPERTIES OF MATHEMATICAL PROGRAMMING MODELS OF STOCHASTIC NETWORK EQUILIBRIUM*

ABSTRACT. Boyce et al. (1981, 1983) have proposed and implementd the use of observed entropy levels to estimate the travel-cost coefficient in mathematical programming models of network equilibrium which involve logit route-choice probabilities. This so-called “dispersion-constrained” model is shown to give severely biased and statistically inefficient underestimates. A natural counterpart, the entropy-maximizing model, is proposed here and overestimates the travel-cost coefficient with much lower bias and much higher statistical efficiency. Even though the two models are mathematically homeomorphic in some respects, they have vastly different statistical properties. It follows that the use of observed entropy levels is undesirable and should be avoided, since maximizing entropy provides an unambiguously superior alternative.     

NEW DIRECTIONS FOR URBAN ECONOMIC MODELS OF LAND USE CHANGE: INCORPORATING SPATIAL DYNAMICS AND HETEROGENEITY*

ABSTRACT We review the usefulness of urban spatial economic models of land use change for the study and policy analysis of spatial land use–environment interactions. We find that meaningful progress has been made in econometric and monocentric models extended to account for multiple sources of spatial heterogeneity and in the development of general equilibrium models with spatial dynamics. Despite these advances, more work is needed in developing models with greater realism. Most agent‐based computational models of urban land use change currently lack economic fundamentals, but provide a flexible means of linking microlevel behavior and interactions with macrolevel land use dynamics. In combination with empirical methods to identify parameters, this framework provides a promising approach to modeling spatial land use dynamics and policy effects.     

MODELS OF MAN'S BIOSOCIAL ADAPTATION IN AN INDUSTRIAL SOCIETY*

The morphological, physiological, and behavioral adaptation of professional athletes can be viewed as a model, being close to the successful hunter's adaptation in a foraging society. Physique, endocrine status, and personality traits were studied in athletes of various professional levels. A set of traits believed to be adaptive for this group is described. Athletes display masculine proportions of head and body, higher testosterone levels, early onset of sexual activity, extroversion, and thoroughness. These fi ndings are discussed from the standpoint of modern ethology and evolutionary anthropology.     

SUPPLY-SIDE MULTIREGIONAL INPUT-OUTPUT MODELS*

ABSTRACT This paper introduces a new class of supply-side multiregional input-output (MRIO) models and provides the necessary and sufficient conditions on the regional trade matrices that ensure that a generalized supply-side model will be convergent. The paper also introduces a new version of the row coefficient model, conceived as the “mirror image” of the Chenery-Moses demand-side column coefficient MRIO model. Given that the conventional supply-side input-output model has been shown to perform equally as well as the demand side model in forecasting exercises, the supply-side MRIO model is expected to be of value for policy and planning purposes. Moreover, this model is of potential theoretical value for a broad synthesis of demand-side and supply-side MRIO models.