Hospital-sponsored networks. The rush to consolidate and the future of medical practice

As the medical delivery system undergoes fundamental change, there is a growing pressure on hospitals to form networks with physicians. The prime motivation for these entities is to preserve market share and fill beds. There is likewise intense pressure on physicians to join them, even if these networks do not serve their best interests, or the goal of fostering physician-centered practice. A transformation is under way, however, that may well place doctors again in the central role of guiding the new modes of medical practice in the United States.     

China's "tidal wave" of migrant labor: what can we learn from Mexican undocumented migration to the United States?

"The purpose of this article is to place Chinese labor migration from agriculture within the context of the literature on labor mobility in developing countries by comparing it to undocumented Mexican migration to the United States. The similarities fall within three general areas: the migration process, the economic and social position of migrants at their destination, and the agrarian structure and process of agricultural development that has perpetuated circular migration. The last section of the article draws upon these similarities, as well as differences between the two countries, to generate predictions concerning the development of labor migration in China."     

Counterurbanisation and rural depopulation revisited: landowners,planners and the rural development process

"This paper reopens the debate between Weekley (1988) and Rowsell (1989) over why pockets of depopulation have persisted within parts of rural Britain which have experienced net growth through counterurbanisation. It argues that Weekley has not fully appreciated the context for local population losses, namely the emergence of a new structural relationship between people, households, and dwellings, and the growing tension between production and consumption interests in rural locales. Moreover, the paper disputes claims that depopulation is triggered by the actions of either the landowner or the planner. Drawing on case study material informed by critical realism, it argues that planners and landowners have been drawn into an asymmetrical power relationship. This has tended to buttress landed interests and, in so doing, reproduce mechanisms which protect the less populous communities from growth and change."     

Migration as a consumption activity

"While a generalized utility maximization approach to migration decisionmaking is not innovative, the principal extensions of this paper involve the search for an instrument capable of measuring changes in utility levels consistent with all preferences (i.e., with all forms of utility functions), requiring only data on observed behaviour. Our approach is to construct a Location-Specific Utility Index (LSUI), whose component variables serve as proxies for the arguments in [U.S.] households' utility functions.... The testable hypothesis is formulated as follows: Assuming constant household preferences and expansion of the household's feasible set over time, the household's utility level is greater following the migration decision.... The results are compared with the households' migration decisions. The empirical evidence shows that migration may reasonably be modelled as a consumption activity by households to maximize utility." (SUMMARY IN FRE AND SPA)     

Evaluation design for a community prevention trial. An environmental approach to reduce alcohol-involved trauma

The Community Prevention Trial was 5-year effort to reduce alcohol-involved injuries and death through a comprehensive program of community awareness and policy activities. The three experimental communities were of approximately 100,000 population each (one in Northern California, one in Southern California, and one in South Carolina). Matched comparison communities were used for each experimental community. This article describes the evaluation approach used in a program that sought to change environmental factors not a specific population or target group. This approach demanded unique evaluation approaches for determining overall community aggregate effects, that is, distal outcomes, as well as changes in key mediating variables, that is, process effects. The problem of trending and lagged effects of community prevention programs are discussed.     

Summing up. Recommendations and experiences for evaluation of community-level prevention programs

This article provides recommendations and observations about evaluation of a locally based prevention project to reduce problems at a total community or aggregate level. The shift from targeting specific individuals or subpopulations to the overall structure and environment of a community is most demanding. Evaluation tools and analysis techniques have lagged behind program development because community-level interventions are not linked to a specific target group who can be separately studied. Thus assumptions about using random assignment and/or comparison communities as means to control for confounding variables are weakened when the unit of analysis is the community itself and dependent measures are subject to trending and the effects of history.     

On the shrinkage of local linear curve estimators

Local linear curve estimators are typically constructed using a compactly supported kernel, which minimizes edge effects and (in the case of the Epanechnikov kernel) optimizes asymptotic performance in a mean square sense. The use of compactly supported kernels can produce numerical problems, however. A common remedy is ridging, which may be viewed as shrinkage of the local linear estimator towards the origin. In this paper we propose a general form of shrinkage, and suggest that, in practice, shrinkage be towards a proper curve estimator. For the latter we propose a local linear estimator based on an infinitely supported kernel. This approach is resistant against selection of too large a shrinkage parameter, which can impair performance when shrinkage is towards the origin. It also removes problems of numerical instability resulting from using a compactly supported kernel, and enjoys very good mean squared error properties.