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.     

Scenarios,uncertainty and conditional forecasts of the world population

This study is concerned with the methods available for the forecasting of future trends in the world's population. Particular attention is given to the problem of the uncertainties that these forecasts include. "The purpose of this paper is to show how subjective and data-based probabilistic assessments of error can be combined, to give a user a realistic assessment of the uncertainty of demographic forecasts, and to apply these concepts to forecasts of the world population. Moreover, we shall show how conditional forecasts can provide a simple conceptual framework in which to view scenarios. They can be particularly useful in the evaluation of proposed policies. Indeed, the so-called environmental impact assessments...that are now mandatory in many countries for major construction projects typically contain elements of conditional forecasting." The concepts discussed are illustrated by comparing a scenario of future global population growth prepared at the Institute of Applied Systems Analysis with a UN population projection.     

Nevada gaming: revenues and taxes (1945-95)

In 1931, Nevada legalized casino gambling, an act which allowed its gaming industry to develop. Because many jurisdictions outside Nevada are now embracing legalized gambling as a path to a brighter economic future and because this proliferation presents Nevada with new challenges and opportunities, it is a good time to review the Nevada experience. Here, the focus is on gaming revenues and gaming tax collections during the 1945–95 period. We find that the growth rate of Nevada's gaming industry has slowed over time, with the relative importance of gaming in the Nevada economy peaking in the late 1970's. The Nevada economy has since been gradually diversifying, something which will increasingly pressure Nevadans to look for government revenue sources other than gaming if current levels of government services are to be maintained.     

"How much do you spend gambling?" ambiguities in survey questionnaire items

The validity of a survey's findings is dependent upon the clarity and lack of ambiguity contained in each individual item yet minimal attention has been directed to this issue in most prevalence studies. Researchers have shown a tendency to accept the uncritical assumption that respondents interpret seemingly simple and straightforward items such as 'how much do you spend gambling?' in a consistent manner. No attempt is made to confirm the uniformity of responses by clarifying the mathematical formulae used by respondents to derive their answers. The purpose of this paper was to examine the consistency shown by a sample of 181 medical undergraduate subjects in estimating the level of gambling expenditure in a series of five case vignettes describing various scenarios of wins and losses during a session of gambling. Results revealed a wide variation in calculated figures depending upon whether or not subjects interpreted the item to mean net expenditure or turnover. Only two thirds or less of subjects calculated the figure to be the difference between the initial amount risked and the residual at the conclusion of the session. It is suggested that more attention be paid in prevalence and clinical studies to providing subjects with clear instructions on how to calculate expenditure estimates.     

Excessively pronated feet: a health hazard to developing children

There is a serious misconception on the part of the public as well as amongst a great number of professionals to equate the problem of flatfoot with excessively pronated feet in growing children. This is a matter of grave concern since flatness of the arch of the foot can be a normal or abnormal finding in foot posture, whereas the excessively pronated foot is flattened as part of a pathological structural malposition. This inherent biomechanical defect is commonly present in the great majority of human children and is the basic reason for most postural pathology of the lower extremity.Excessive pronation of the feet in children should in no way be interpreted as a normal condition to be automatically outgrown. As a matter of fact, Whitman, the famous Orthopaedic Surgeon, noted in 1917 in his text Orthopaedic Surgery that pronation of the feet commonly seen in children is more likely to worsen than improve over the years. This paper presents the probable cause of the condition, treatment and prevention of the problem and recommendations for the future.The deforming foot posture known as excessive pronation is familiar to Podiatric Medicine and to Medicine generally. Yet, in spite of this familiarity, only an insignificant number of the millions of children in our country receive the simple available help required to minimize the problem.The Podiatric profession has within its grasp the wherewithal to correct this situation, through education and counseling of parents, through cooperation with pediatricians and other professionals and by utilizing technological advances in children's footgear and orthotics. It is the intention of this paper to provide an overview of the literature and history associated with the problem of excessive pronation in children, as well as to suggest some simple techniques for improving this situation.Dr. Tax is an international renowned consultant to many Podiatric Hospital amon which is the Veterans Administration in New Jersey, New York College of Podiatric Medicine, Ohio College of Podiatric Medicine. He has written and lectured extensively on the subject of children and problems with their feet.     

Treatment issues for survivors of physical and sexual abuse*

Many clients who participate in family therapy have experienced trauma such as physical and sexual abuse in their families of origin. Extensive literature suggests that abusive experiences can result in post-traumatic stress disorders, depression, anxiety, personality disorders, and other long-term effects. Without recognition of the effects that abuse can have on individuals, it is possible to misdiagnose clients or fail to provide them with adequate assistance. This study is an attempt to compare the symptomology of nonabused clients with physically and sexually abused clients using an empirically sound measure. The results demonstrate that the majority of clients who experienced physical and/or sexual abuse in their backgrounds scored in the clinical range on scales from the Millon Clinical Multiaxial Instrument (MCMI) (Millon, 1984). In contrast, clients who did not report abuse had significantly lower scores than the abused clients, and the majority of the nonabused clients scored in the nonclinical range on the scales of the MCMI. Treatment and theoretical implications surrounding the issues of abuse are discussed, and recommendations for marriage and family therapists are provided.     

Subsidized elderly housing: public-private partnerships on the brink

Starting in the early 1960s, the federal government joined with the private-sector housing developers in a partnership: in return for subsidized mortgages and tax benefits, developers would rent to low- and moderate-income tenants. Today, many elderly people live in these "publicly subsidized" units. The initial agreement, however, held out an escape clause: after 15 to 20 years, for-profit developers that wanted to end the partnership could prepay their mortgages, leaving tenants in those buildings "at risk" of rent increases and/or evictions. This article discusses that partnership, its options for dissolution, and the current solutions to the problem of the expiring agreements, including a moratorium, vouchers, and incentives. The compromise legislation responds to all interested parties--owners, current and would-be tenants, local governments, tax-payers--through a multi-stage sequence of dissolution, yet such a finely tuned, acutely sensitive legislative solution may not work easily or efficiently.     

A guide to journal articles on strategic management in nonprofit organizations, 1977 to 1992

This article is a guide to over a hundred journal articles on strategic management in nonprofit organizations, published from 1977 to 1992 in nineteen leading general management or nonprofit journals. The guide provides brief summaries of articles, organized into widely accepted strategic management topic areas and research categories. The article indicates areas where substantial foundations of knowledge exist and where such bases are lacking. It distinguishes between works on general nonprofit management and those on empirical research.     

The double-edged sword of social service contracting: public accountability versus nonprofit autonomy

The increased role of government contracts in the funding of nonprofits has heightened tensions as governments seek accountability and nonprofits seek to preserve autonomy. Considering both sides of the contract market this article suggests that the threat of government funding is exaggerated. Nonprofits are attractive contractor options because of their experience and trustworthiness. Governments should recognize that excessive intrusions limit the advantages of the nonprofit sector. At the same time, nonprofits should be conscious of the implications of public funding, just as they must be of other sources of funding.     

A probablistic analysis for an optimal screening problem

Summary We consider a lotL formed byN apparently similar unitsW ₁,…,W _N, where each of theW _i may come from one of two different populationsP ₁ andP ₂;T ₁,…,T _N denote the corresponding lifetimes. The units fromP _i undergo a failure of kindi and their survival function isS _i (t). We assume that the failure rate function are known and that the units fromP ₁ are ?substandard?: λ ₁ (t)≥λ ₂ (t), ∀t≥0. We want to putW ₁,…,W _N under a pre-operational test (burn-in test) in order to eliminate at least a great part of the substandard units and we face the problem of obtaining a rule for stopping the test under the assumption that, with the failure of a unit, it is possible to recognize the population from which the unit comes. Such a problem will be formalized as an optimal stopping problem for a suitably defined Markov process. Our study shall evidentiate some fundamental aspects of the problem and the role of the prior distribution of the (random) numberM ₀ of those units inL coming fromP ₁ (substandard). The latter distribution has a great influence on the form of the solution. This research was supported by the C.N.R. Project ?Statistica Bayesiana e Simulazione in Affidalità e Modellistica Biologica?.