Detecting multiple change points in piecewise constant hazard functions

The National Cancer Institute (NCI) suggests a sudden reduction in prostate cancer mortality rates, likely due to highly successful treatments and screening methods for early diagnosis. We are interested in understanding the impact of medical breakthroughs, treatments, or interventions, on the survival experience for a population. For this purpose, estimating the underlying hazard function, with possible time change points, would be of substantial interest, as it will provide a general picture of the survival trend and when this trend is disrupted. Increasing attention has been given to testing the assumption of a constant failure rate against a failure rate that changes at a single point in time. We expand the set of alternatives to allow for the consideration of multiple change-points, and propose a model selection algorithm using sequential testing for the piecewise constant hazard model. These methods are data driven and allow us to estimate not only the number of change points in the hazard function but where those changes occur. Such an analysis allows for better understanding of how changing medical practice affects the survival experience for a patient population. We test for change points in prostate cancer mortality rates using the NCI Surveillance, Epidemiology, and End Results dataset.     

Blurring the Lines Between Civil Society,Volunteering and Social Movements. A Reflection on Redrawing Boundaries Inspired by the Spanish Case

Citizen participation is manifested through various concepts, such as activism, social movements, volunteering or civil society. The different ways of understanding popular engagement are often separated by delimitations that define them, particularly volunteering and civic action, as two highly differentiated forms of participation in the distinct academic disciplines: political science, volunteering studies, social movement studies or civil society theory. This article considers whether this basic theoretical differentiation can be problematised in the Spanish political context by exploring four paradigmatic cases of popular engagement, using qualitative case study methodology, specifically, a historic case from the 1990s and three more recent cases. It is hoped that the results of the study—which differentiates between organisational hybridity and fuzziness—will encourage reflection on the traditional boundaries between different forms of popular engagement.     

Episodic Volunteering at a Religious Megaevent

In preparation for Pope Francis's visit to Philadelphia and the 2015 World Meeting of Families, organizers looked for thousands of volunteers to help carry out these events. This is common for many one‐time and episodic events, such as large sporting events (from marathons to Special Olympics), arts and cultural events (such as festivals and concerts), and fundraising events. After the pope's visit, volunteers were asked to respond to a questionnaire about their experiences and the volunteer management of the event; 2,408 responded (34.4 percent). Data on motivation, who volunteered, recruitment, training, assignment, supervision, communication, satisfaction, and suggestions for improvement were elicited. We focused on episodic volunteering at a religious event and on a broad spectrum of issues pertaining to management of episodic volunteers. Our findings add to the knowledge regarding volunteer management and also add to conceptual understanding of the distinction between ongoing and episodic volunteers.     

Socioemotional wealth’s implications in the calculus of the minimum rate of return required by family businesses’ owners

This paper demonstrates that the minimum rate of return (k _e ) required by family business shareholders is inversely related to the emotional endowment presented in these firms. After reviewing the socioemotional wealth (SEW) literature, we find empirical support to justify that different SEW dimensions influence k _e . Findings from a population of 207 family firms show that the identification of family members with the firm and the renewal of family bonds with the firm through dynastic succession have consistently negative impacts on k _e , while family control and influence have significantly positive impacts on k _e .     

Welfare gains of the poor: An endogenous Bayesian approach with spatial random effects

We introduce a Bayesian instrumental variable procedure with spatial random effects that handles endogeneity, and spatial dependence with unobserved heterogeneity. We find through a limited Monte Carlo experiment that our proposal works well in terms of point estimates and prediction. We apply our method to analyze the welfare effects generated by a process of electricity tariff unification on the poorest households. In particular, we deduce an Equivalent Variation measure where there is a budget constraint for a two-tiered pricing scheme, and find that 10% of the poorest municipalities attained welfare gains above 2% of their initial income.     

A Dynamic Model of Product Quality and Pricing Decisions on Sales Response

This paper presents a dynamic model that examines the influence of price and customer perception of product quality on the sales rate of a firm producing durable goods. The sales rate of the firm is modeled as a function of its price, average product life, perceived quality, and market potential. Specifically, the model considers: (1) the process by which perceived quality is determined by including the effects of the average life of a product and quality weighted units in the market; (2) the time delay in the influence of actual quality on perceived quality; (3) the process by which demand (i.e., potential sales) is converted to realized sales due to the effects of price and perceived quality; and (4) the saturation effect and associated non-linearity in the demand function. The model presented is a reformulation and extension of the model originally proposed by Bass [2]. The validity of the model is tested using historical data on For Mustang.     

ON FUZZY GOAL PROGRAMMING—SOME COMMENTS

This paper pertains to goal programming with fuzzy goals and fuzzy priorities. Hannan [1], in his paper on fuzzy goal programming, alludes to the difficulty of handling fuzzy priorities and further notes that a method that this author proposed [2] may lead to incorrect results. In this note, the general problem of goal programming with fuzzy priorities is reexamined, along with the solution to the specific example presented in my original paper [2]. It is shown that the method for handling fuzzy priorities originally proposed by this author does indeed capture the relative importance of goals.     

The Reform of the Local Social Services In Israel: 1984 Compared to 1977

In 1977, there was a nationwide reform of the Local Departments of Social Services (LDSS) in Israel. This article reports on the findings of two independent and complementary studies which sought to evaluate the consequences of this comprehensive planned change. To determine what changes if any, occurred from 1977 to 1984, the first seven years following the reform, the article presents seven major foci of change. Each reflects an objective set forth by those who planned the change at the Ministry of Labour and Social Affairs. Preceding the report of these changes are a review of the historical background of the reform and a summary of the components of this planned change. This article focuses on the changes identified in these studies and concludes with a discussion of policy and organizational implications.     

Bayesian Estimation of the Log–linear Exponential Regression Model with Censorship and Collinearity

In this work, a simulation study is conducted to evaluate the performance of Bayesian estimators for the log–linear exponential regression model under different levels of censoring and degrees of collinearity for two covariates. The diffuse normal, independent Student-t and multivariate Student-t distributions are considered as prior distributions and to draw from the posterior distributions, the Metropolis algorithm is implemented. Also, the results are compared with the maximum likelihood estimators in terms of the mean squared error, coverages and length of the credibility and confidence intervals.