An extended semiparametric model for short-term and long-term hazard ratios

In survival analysis, one way to deal with non-proportional hazards is to model short-term and long-term hazard ratios. The existing model of this nature has no control over how fast the hazard ratio is changing over time. We add a parameter to the existing model to allow the hazard ratio to change over time at different speed. A nonparametric maximum likelihood approach is used to estimate the model parameters. The existing model is a special case of the extended model when the speed parameter is 0, which leads naturally to a way of testing the adequacy of the existing model. Simulation results show that there can be substantial bias in the estimation of the short-term and long-term hazard ratio if the speed parameter is fixed incorrectly at 0 rather than estimated. The extended model is fitted to three real data sets to shed new insights, including the observation that converging hazards does not necessarily imply the odds are proportional.     

From design to operations: a process management life-cycle performance measurement system for Public-Private Partnerships

Public–Private Partnerships (PPPs) have become a critical vehicle for delivering infrastructure worldwide. Yet, the use of such a procurement strategy has received considerable criticism, as they have been prone to experiencing time/cost overruns and during their operation poorly managed. A key issue contributing to the poor performance of PPPs is the paucity of an effective and comprehensive performance measurement system. There has been a tendency for the performance of PPPs to be measured based on their ex-post criteria of time, cost and quality. Such criteria do not accommodate the complexities and lifecycle of an asset. In addressing this problem, the methodology of sequential triangulation is used to develop and examine the effectiveness of a ‘Process Management Life Cycle Performance Measurement System’. The research provides public authorities and private-sector entities embarking on PPPs with a robust mechanism to effectively measure, control and manage their projects’ life cycle performances, ensuring the assets are ‘future proofed’.     

Politics and Scientific Expertise: Scientists, Risk Perception, and Nuclear Waste Policy

To study the homogeneity and influences on scientists'perspectives of environmental risks, we have examined similarities and differences in risk perceptions, particularly regarding nuclear wastes, and policy preferences among 1011 scientists and engineers. We found significant differences ( p 0.05)in the patterns of beliefs among scientists from different fields of research. In contrast to physicists, chemists, and engineers, life scientists tend to: (a)perceive the greatest risks from nuclear energy and nuclear waste management; (b)perceive higher levels of overall environmental risk; (c)strongly oppose imposing risks on unconsenting individuals; and (d)prefer stronger requirements for environmental management. On some issues related to priorities among public problems and calls for government action, there are significant variations among life scientists or physical scientists. We also found that–independently of field of research–perceptions of risk and its correlates are significantly associated with the type of institution in which the scientist is employed. Scientists in universities or state and local governments tend to see the risks of nuclear energy and wastes as greater than scientists who work as business consultants, for federal organizations, or for private research laboratories. Significant differences also are found in priority given to environmental risks, the perceived proximity of environmental disaster, willingness to impose risks on an unconsenting population, and the necessity of accepting risks and sacrifices.     

Communicating Geographical Risks in Crisis Management: The Need for Research

In any crisis, there is a great deal of uncertainty, often geographical uncertainty or, more precisely, spatiotemporal uncertainty. Examples include the spread of contamination from an industrial accident, drifting volcanic ash, and the path of a hurricane. Estimating spatiotemporal probabilities is usually a difficult task, but that is not our primary concern. Rather, we ask how analysts can communicate spatiotemporal uncertainty to those handling the crisis. We comment on the somewhat limited literature on the representation of spatial uncertainty on maps. We note that many cognitive issues arise and that the potential for confusion is high. We note that in the early stages of handling a crisis, the uncertainties involved may be deep, i.e., difficult or impossible to quantify in the time available. In such circumstance, we suggest the idea of presenting multiple scenarios.     

Asymptotic distributions for the intervals estimators of the extremal index and the cluster-size probabilities

Under appropriate long range dependence conditions, the point process of exceedances of a stationary sequence weakly converges to a homogeneous compound Poisson point process. This limiting point process can be characterized by the extremal index and the cluster-size probabilities. In this paper we address the problem of estimating these quantities and we consider the intervals estimators introduced in Ferro and Segers [2003. Inference for clusters of extreme values. J. Roy. Statist. Soc. Ser. B 545–556] and in Ferro [2004. Statistical methods for clusters of extreme values. Ph.D. Thesis, Lancaster University]. We establish asymptotic weak convergence to Gaussian random variables and we give their asymptotic variance.     

Adolescent parenthood,economic issues,and social policies

Adolescent parenthood has highly publicized adverse social and economic consequences, but these same social and economic disadvantages can be viewed as root causes of adolescent pregnancy. Recent research and revisionist debates about these issues are reviewed and summarized. Diverse implications for social policy are considered. Prevention approaches are emphasized that build on both postponing adolescent sexual intercourse and helping sexually active teens avoid pregnancy.Appreciation is expressed to Christine Bachrach and Kristin Moore for their comments on a previous version of this paper.Dr. Miller's current research interests are the family antecedents of adolescent sexual behavior and the design and evaluation of prevention programs for adolescent problem behaviors. He received his Ph.D. in family sociology from the University of Minnesota in 1975.     

Professional Relationship Boundaries: A Social Work Teaching Module

Social workers are often challenged by the complex and ever‐changing dynamics within their relationships with clients, and struggle to find ethical responses within professional boundary grey zones where boundaries with clients can be difficult to identify, yet easy to cross. Social work educators attempt to prepare students for these complex situations, yet in the United States research reveals rates of social work boundary violations that lead one to question the efficacy of social work ethics education. This article describes the educational competencies and instructional strategies that comprise an adaptable course module which was developed in response to this challenge, and intended to increase students' self‐awareness, motivation and professional judgment‐making abilities related to their professional boundaries. The educational competencies for this course include the abilities to: identify boundary violations, apply critical thinking skills to complex professional relationship contexts, increase awareness of self and other, and initiate prevention strategies. In contrast to traditional approaches to education, this article describes instructional strategies that are based on adult‐learning principles, which have the purpose of effectively and creatively teaching topic areas in such a way as to produce behavioural change. These course topic areas include a ‘Professional Relationship Boundaries Continuum’ conceptual framework, boundary violation impacts, personal boundary vulnerabilities, blurring boundary indicators, and risk‐minimizing strategies.     

“Something More”: The Meanings of Marriage for Religious Couples in America

This study focused on how couples’ beliefs about marriage and religion shape the meanings they find in their marriage. Interviews about connections between religion and marriage were conducted with 57 Christian, Jewish, and Muslim couples in New England and northern California. Qualitative analyses found the major theme, common across faith traditions, was that marriage is a sacred union that is “something more": more than the self, more than the couple, and more than the family unit. To these couples marriage is divine and institutional and a vital support for their relationship. Our findings raise an interesting counterpoint to the current scholarly discourse about the deinstitutionalization and individualization of contemporary marriage. Institutionalized features of marriage may retain their strength in contemporary society as many religious couples, and perhaps many other couples as well, believe marriage is something more than the deinstitutionalized, private relationship that many scholars now see.