A monte carlo investigation of a statistic for a bivariate missing data problem

Testing the equal means hypothesis of a bivariate normal distribution with homoscedastic varlates when the data are incomplete is considered. If the correlational parameter, ρ, is known, the well-known theory of the general linear model is easily employed to construct the likelihood ratio test for the two sided alternative. A statistic, T, for the case of ρ unknown is proposed by direct analogy to the likelihood ratio statistic when ρ is known. The null and nonnull distribution of T is investigated by Monte Carlo techniques. It is concluded that T may be compared to the conventional t distribution for testing the null hypothesis and that this procedure results in a substantial increase in power-efficiency over the procedure based on the paired t test which ignores the incomplete data. A Monte Carlo comparison to two statistics proposed by Lin and Stivers (1974) suggests that the test based on T is more conservative than either of their statistics.     

Fisher's Hypergeometric Test for a Comparison in a Finite Population

Graphical methods have played a central role in the development of statistical theory and practice. This presentation briefly reviews some of the highlights in the historical development of statistical graphics and gives a simple taxonomy that can be used to characterize the current use of graphical methods. This taxonomy is used to describe the evolution of the use of graphics in some major statistical and related scientific journals.

Some recent advances in the use of graphical methods for statistical analysis are reviewed, and several graphical methods for the statistical presentation of data are illustrated, including the use of multicolor maps.     

Gay,Lesbian, and Heterosexual Couples About to Begin Couples Therapy: An Online Relationship Assessment of 40,681 Couples

We currently have little idea of precisely who goes for couples therapy. This is a report of the results of a validated online assessment of relationship and individual functioning based on 39,251 heterosexual, 1,022 lesbian, and 438 gay couples about to begin couples therapy. Using validated and reliable questionnaires of relationship and individual functioning, this report presents and compares, for each sexual-orientation, the percentage of couples, pre-therapy, who are coping with a variety of relationship problems. To test for the replicability of results, the sample was divided randomly into two subsamples and statistical tests were performed on each sample. Couples initiating therapy suffer from greater distress and many more co-morbidities than has been presumed in previous literature, and same-sex couples present a particular set of both strengths and challenges compared to heterosexual couples. Gay-male and lesbian couples were very different on trust and monogamy, as were heterosexual and lesbian couples. Based on this epidemiologically sized sample, the challenge to our field may be to create interventions with much larger effect sizes than we currently have.     

A Network Therapy Clinic for Clients with Intellectual Disability

Over the past 30 years a systemic approach has been applied to complex cases involving intellectual disability and behaviours of concern. This paper describes a model that draws on systemic family therapy and network therapy as well as the use of a reflective team. A single session intervention was provided for families of people with intellectual disability. A systemic consultation was used as a pre‐session meeting for professionals working with the family. The systemic consultation and single session therapy allowed the family and the professional network to gain insight. Involving the professionals in the therapy session also enhanced the alliance between professionals and family. This approach assists everyone involved in the case to find a way to progress.     

Physician credentialing. A centralized verification system

The current system for credentialing physicians in the U.S. is staggeringly redundant, prone to error, and expensive. The process for establishing a recent graduate's practice can involve an average of five applications to have privileges at several hospitals and HMOs. A centralized verification system needs to be developed to streamline this process. The amount of information that would have to be stored for all physicians in the country would be immense. However, the technology currently exists to store such information on a much grander scale. Credit unions, banks, and insurance companies utilize such computer systems effectively and with reasonable confidentiality.     

Principles for Conduct of Pest Risk Analyses: Report of an Expert Workshop

The North American Free Trade Agreement (NAFTA) and the General Agreement on Tariffs and Trade (GATT) have focused attention on risk assessment of potential insect, weed, and animal pests and diseases of livestock. These risks have traditionally been addressed through quarantine protocols ranging from limits on the geographical areas from which a product may originate, postharvest disinfestation procedures like fumigation, and inspections at points of export and import, to outright bans. To ensure that plant and animal protection measures are not used as nontariff trade barriers, GATT and NAFTA require pest risk analysis (PRA) to support quarantine decisions. The increased emphasis on PRA has spurred multiple efforts at the national and international level to design frameworks for the conduct of these analyses. As approaches to pest risk analysis proliferate, and the importance of the analyses grows, concerns have arisen about the scientific and technical conduct of pest risk analysis. In January of 1997, the Harvard Center for Risk Analysis (HCRA) held an invitation-only workshop in Washington, D.C. to bring experts in risk analysis and pest characterization together to develop general principles for pest risk analysis. Workshop participants examined current frameworks for PRA, discussed strengths and weaknesses of the approaches, and formulated principles, based on years of experience with risk analysis in other setting and knowledge of the issues specific to analysis of pests. The principles developed highlight the both the similarities of pest risk analysis to other forms of risk analysis, and its unique attributes.     

Evidence‐based Management in Practice: Opening up the Decision Process,Decision‐maker and Context

Evidence‐based management (EBM) has been subject to a number of persuasive critiques in recent years. Concerns have been raised that: EBM over‐privileges rationality as a basis for decision‐making; ‘scientific’ evidence is insufficient and incomplete as a basis for management practice; understanding of how EBM actually plays out in practice is limited; and, although ideas were originally taken from evidence‐based medicine, individual‐situated expertise has been forgotten in the transfer. To address these concerns, the authors adopted an approach of ‘opening up’ the decision process, the decision‐maker and the context (Langley et al. ( 1995 ). ‘Opening up decision making: the view from the black stool’, Organization Science, 6, pp. 260–279). The empirical investigation focuses on an EBM decision process involving an operations management problem in a hospital emergency department in Australia. Based on interview and archival research, it describes how an EBM decision process was enacted by a physician manager. It identifies the role of ‘fit’ between the decision‐maker and the organizational context in enabling an evidence‐based process and develops insights for EBM theory and practice.     

Aiming for Excellence: Reflections on the Advanced Institute of Management Research and its Elite

In 2002, the UK government launched the Advanced Institute of Management Research, a major initiative intended to raise the quality of research in business schools. Rather than offering research grants in open competition, AIM deliberately funded a select few leading lights in management. Insufficient allowance was made for the Research Assessment Exercise, which measured research excellence in terms of papers published in top journals. The AIM's elite exploited its existing publishing advantage, and AIM provided further resources to aid their efforts. The AIM recruited willing acolytes to work with its elite in fashioning the sort of papers required by the top journals of management – positive papers, consensual and endlessly citable. Analysis of the publishing patterns of AIM senior fellows reveals research cliques and publication silos rather than a network organization. Much as the elite saw its AIM funding as recognition of its own excellence, so AIM itself came to be seen as acknowledgement of the excellence of management research as a whole. That AIM existed to raise management research from intellectual poverty was forgotten. The AIM was wound up in 2012, having spent £30 million, most of it on the subject's elite. The problems that beset management research remain.     

Image warping using radial basis functions

Image warping is the process of deforming an image through a transformation of its domain, which is typically a subset of R². Given the destination of a collection of points, the problem becomes one of finding a suitable smooth interpolation for the destinations of the remaining points of the domain. A common solution is to use the thin plate spline (TPS). We find that the TPS often introduces unintended distortions of image structures. In this paper, we will analyze interpolation by TPS, experiment with other radial basis functions, and suggest two alternative functions that provide better results.