An Outcomes-Based Assessment of Quality of Life in Social Services

The goal of this article consists of describing the calibration of an instrument to assess quality of life-related personal outcomes using Rasch analysis. The sample was composed of 3.029 recipients of social services from Catalonia (Spain) and was selected using a probabilistic polietapic sample design. Results related to unidimensionality, item and person separation reliability, calibration, items’ level of difficulty, response categories and differential item functioning by gender and type of collective are provided and point out the general fit of the data to the model. However, it is recommended to include more difficult items and eliminate one that seems not to be adequate.     

Sojourning With the Homogeneous Poisson Process

In this pedagogical article, distributional properties, some surprising, pertaining to the homogeneous Poisson process (HPP), when observed over a possibly random window, are presented. Properties of the gap-time that covered the termination time and the correlations among gap-times of the observed events are obtained. Inference procedures, such as estimation and model validation, based on event occurrence data over the observation window, are also presented. We envision that through the results in this article, a better appreciation of the subtleties involved in the modeling and analysis of recurrent events data will ensue, since the HPP is arguably one of the simplest among recurrent event models. In addition, the use of the theorem of total probability, Bayes’ theorem, the iterated rules of expectation, variance and covariance, and the renewal equation could be illustrative when teaching distribution theory, mathematical statistics, and stochastic processes at both the undergraduate and graduate levels. This article is targeted toward both instructors and students.     

The Other Side of Ownership in Nonprofit Organizations: an Economic Rationale for Democracy

Going beyond the deeply examined non-distribution constraint, which refers to the right to residual income, the paper investigates the other side of ownership, i.e. the right to residual control, to discover a general economic rationale for what we call “democracy”: a collective decision-making method based on the principles of equality and inclusiveness. The main result of the analysis is to point to the concept of perfect democracy as an efficient solution for the provision of public goods where other allocative mechanisms, such as the marketplace, fail.     

Censored Exponential Data: Large Deviations for MLEs and Posterior Distributions

In this article, we consider several statistical models for censored exponential data. We prove a large deviation result for the maximum likelihood estimators (MLEs) of each model, and a unique result for the posterior distributions which works well for all the cases. Finally, comparing the large deviation rate functions for MLEs and posterior distributions, we show that a typical feature fails for one model; moreover, we illustrate the relation between this fact and a well-known result for curved exponential models.     

Weighted likelihood latent class linear regression

Statistical Methods & Applications - A weighted likelihood approach for robust fitting of a finite mixture of linear regression models is proposed. An EM type algorithm and its variant based on...     

Total least squares and bootstrapping with applications in calibration

The solution to the errors-in-variables problem computed through total least squares is highly nonlinear. Because of this, many statistical procedures for constructing confidence intervals and testing hypotheses cannot be applied. One possible solution to this dilemma is bootstrapping. A nonparametric bootstrap technique could fail. Here, the proper nonparametric bootstrap procedure is provided and its correctness is proved. On the other hand, a residual bootstrap is not valid and suitable in this case. The results are illustrated through a simulation study. An application of this approach to calibration data is presented.     

The unusual genetics of human longevity

In no species other than humans do cultural, social, and biological factors interact with each other in modulating complex phenotypes. Thus, the identification of genetic factors that affect human longevity is a true challenge. The model of centenarians provides us a unique opportunity to tackle this challenge. In this Perspective, we discuss some recent findings (the impact of geography and demography on the longevity phenotype, the relationship between longevity and homozygosity, the role of the nuclear-mitochondrial genome cross-talk) by which new ideas are suggested, such as the concept of a complex allele timing as a pivotal process in modulating the probability of achieving longevity.     

Well-Being and Affective Commitment among Ambulance Volunteers: A Mediational Model of Job Burnout

ABSTRACT

Burnout represents a relevant risk for ambulance volunteers. According to the Job Demands-Resources model, role conflict and social support can be considered as antecedents of burnout which, in turn, may lower affective commitment. This study aims to investigate the relationship between social support, role conflict, and affective commitment, as mediated by job burnout. Survey data were collected from 352 Italian volunteers and analyzed using structural equation modeling methods. Social support was confirmed as a protective factor, and role conflict as an antecedent of burnout which, in turn, decreases affective commitment. The relationship between role conflict and affective commitment is mediated by burnout which, on the contrary, does not mediate the effect of social support on affective commitment. Social support may protect against burnout. Because of its positive effects on a personal and an organizational level, affective commitment may be increased raising levels of supervisor support and reshaping role expectations. It could be useful to carry out future longitudinal studies, in order to confirm the antecedents and effects of job burnout; furthermore, this research should be extended to other ambulance organizations, in order to generalize the results; finally, multi-group analyses would allow to bring out possible differences between paid-staff and volunteers.     

Priority Topics in the Study of Environmental Risk in Developing Countries: Report on a Workshop Held at the East–West Center, August, 1988

The rapid industrialization occurring in developing regions of the world brings not only economic benefits, but changes in the types and severity of health and environmental problems that each region experiences. As the industrialized world moves toward the use of risk assessment methodologies to aid in problem evaluation and regulatory and policy decision analysis, it seems inevitable that these methodologies will be applied globally. The changes brought about by rapid industrialization, however, must be viewed within the context of societies that are still struggling with the more traditional and basic environmental problems associated with urban and rural poverty. The urgency of development and the lack of adequate resources for characterizing health and environmental changes, often present under these circumstances, offer special challenges to the application of risk assessment methodologies.