Bayes and robust Bayes predictions in a subfamily of scale parameters under a precautionary loss function

ABSTRACT

This paper deals with Bayes, robust Bayes, and minimax predictions in a subfamily of scale parameters under an asymmetric precautionary loss function. In Bayesian statistical inference, the goal is to obtain optimal rules under a specified loss function and an explicit prior distribution over the parameter space. However, in practice, we are not able to specify the prior totally or when a problem must be solved by two statisticians, they may agree on the choice of the prior but not the values of the hyperparameters. A common approach to the prior uncertainty in Bayesian analysis is to choose a class of prior distributions and compute some functional quantity. This is known as Robust Bayesian analysis which provides a way to consider the prior knowledge in terms of a class of priors Γ for global prevention against bad choices of hyperparameters. Under a scale invariant precautionary loss function, we deal with robust Bayes predictions of Y based on X. We carried out a simulation study and a real data analysis to illustrate the practical utility of the prediction procedure.     

Inference on proportional hazard rate model parameter under Type-I progressively hybrid censoring scheme

ABSTRACT

In this paper, under Type-I progressive hybrid censoring sample, we obtain maximum likelihood estimator of unknown parameter when the parent distribution belongs to proportional hazard rate family. We derive the conditional probability density function of the maximum likelihood estimator using moment-generating function technique. The exact confidence interval is obtained and compared by conducting a Monte Carlo simulation study for burr Type XII distribution. Finally, we obtain the Bayes and posterior regret gamma minimax estimates of the parameter under a precautionary loss function with precautionary index k = 2 and compare their behavior via a Monte Carlo simulation study.     

Legal liability: A professional concern

Recent jurisprudence should direct the attention of social workers to two areas of possible legal liability in their professional activities. The ethical responsibility for keeping a client's communications confidential may be outweighed by the broader obligation to protect a victim from a client's violence by reporting threats to legal authorities. Damage action against physicians for failure to report suspected child abuse opened the door to civil liability to others who have a mandatory reporting responsibility.     

Perspective: Risk Apportionment and Disease Intervention Strategies

The ultimate public health objective is the ability to predict and prevent disease, and not necessarily to identify an exhaustive list of potential disease risk factors. For any important public health outcome with multiple and potentially interrelated risk factors, an improved understanding of the contribution of individual and combinations of modifiable risk factors to the disease burden is essential for formulating an appropriate public health strategy. Partitioning techniques that divide the combined impact of multiple risk factors into exposure-specific components while taking into account the potential interrelations among those components, have been described in the epidemiological literature. In this article, we review and compare the available methods and options for such apportionment and apply them in a more general public health context as a method of selecting and prioritizing coronary heart disease (CHD) prevention strategies.     

Volunteer Behavior and Factors that Influence Volunteering Among Residents in Continuing Care Retirement Communities

The purpose of this survey was to explore volunteer preferences, perceived benefits and barriers, and the factors that influence volunteering among older adults living in a continuing care retirement community. This was a single group, one-time survey completed via a face-to-face interview. The sample included 127 older adults who were eligible and completed the survey. The majority were women (78%) and White (98%), with an average age of 88.0 (SD = 6.5) years. Engagement in volunteer activities ranged from 0 to 7, with a mean of .94 (SD = 1.30). Just under half (47%) of the participants were engaged in volunteer work, with the majority (87%) volunteering within the facility. Perceived benefits and barriers to volunteering were described. Chronic illness, age, time spent exercising, and resilience accounted for 25% of the variance in volunteer activity. Those who had fewer chronic illnesses, were younger, spent more time exercising, and were more resilient were more likely to volunteer. Findings from this study suggest that there are advantages to offering volunteer activities within senior living facilities. Ongoing study is needed to develop and implement successful facility-specific volunteer programs.     

Developmental Social Policy,Social Welfare Services and the Non‐profit Sector in South Africa

The potential and challenge of constructing a democratic developmental welfare state through synergistic state‐civil society relations is the focus of this article. The author argues that while South Africa's pluralist approach, involving a leading role for the state in partnership with voluntary organizations, is a viable policy option to address the country's developmental challenges, anomalies between policy proclamations and actual practice raises questions about the efficacy of the partnership model and the gendered nature of welfare provision. Key governance issues and challenges, namely financial policies and institutional capability, underlie current failures in the delivery of welfare and care services, resulting in the non‐realization of these constitutionally guaranteed social rights. Further public action is needed to remedy the situation. Non‐profit organizations can advocate for policy reforms and challenge the instrumental nature of state‐civil relations and the abrogation of state responsibility for welfare services in contemporary South Africa.     

Confirmatory Factor Analysis of the End‐User Computing Satisfaction Instrument: Replication within an ERP Domain*

Over the past decade, organizations have made significant investments in enterprise resource planning (ERP) systems. The realization of benefits from these investments depends on supporting effective use of information technology (IT) and satisfying IT users. User satisfaction with information systems is one of the most important determinants of the success of those systems. Drawing upon a sample of 407 end users of ERP systems and working within the framework of confirmatory factor analysis (CFA), this study examines the structure and dimensionality, and reliability and validity of the end‐user computing satisfaction (EUCS) instrument posited by Doll and Torkzadeh (1988) . In response to Klenke's (1992) motion to cross‐validate management information system (MIS) instruments and to retest the end user computing satisfaction instrument using new data, this study's results, consistent with previous findings, confirm that the EUCS instrument maintains its psychometric stability when applied to users of enterprise resource planning application software. Implications of these results for practice and research are provided.     

Inference based on progressively censored sample from Pareto population

Abstract

In this paper, we assume that the lifetimes have a two-parameter Pareto distribution and discuss some results of progressive Type-II censored sample. We obtain maximum likelihood estimators and Bayes estimators of the unknown parameters under squared error loss and a precautionary loss functions in progressively Type-II censored sample. Robust Bayes estimation of unknown parameters over three different classes of priors under progressively Type-II censored sample, squared error loss, and precautionary loss functions are obtained. We discuss estimation of unknown parameters on competing risks progressive Type-II censoring. Finally, we consider the problem of estimating the common scale parameter of two Pareto distributions when samples are progressively Type-II censored.     

A Comparison of Egg Consumption with Other Modifiable Coronary Heart Disease Lifestyle Risk Factors: A Relative Risk Apportionment Study

Guidelines from the American Heart Association (AHA) recommend that healthy adults limit their intake of dietary cholesterol to less than 300 mg per day. Since a large egg contains about 71% of that amount, the AHA recommends restricting egg consumption unless dietary cholesterol intakes from other sources are limited. We applied a risk apportionment approach to estimate the contribution of egg consumption and other modifiable lifestyle risk factors (e.g., smoking, poor diet, minimal exercise, and alcohol intake) to coronary heart disease (CHD) risk at the population level. Specifically, we categorized the U.S. adult population ages 25+ into distinct risk groups based on the prevalence of modifiable lifestyle risk factors and applied an apportionment model, typically used to assess risk contribution at the individual level, to estimate the contribution of egg intake to CHD risk. Our analysis shows that the combination of modifiable lifestyle risk factors accounts for less than 40% of the population CHD mortality. For the majority of U.S. adults age 25+, consuming one egg a day accounts for <1% of CHD risk. Hence, focusing on decreasing egg intake as an approach to modify CHD risk would be expected to yield minimal results relative to changing other behaviors such as smoking and other dietary habits.