Bayesian bivariate survival analysis using the power variance function copula

Copula models have become increasingly popular for modelling the dependence structure in multivariate survival data. The two-parameter Archimedean family of Power Variance Function (PVF) copulas includes the Clayton, Positive Stable (Gumbel) and Inverse Gaussian copulas as special or limiting cases, thus offers a unified approach to fitting these important copulas. Two-stage frequentist procedures for estimating the marginal distributions and the PVF copula have been suggested by Andersen (Lifetime Data Anal 11:333–350, 2005), Massonnet et al. (J Stat Plann Inference 139(11):3865–3877, 2009) and Prenen et al. (J R Stat Soc Ser B 79(2):483–505, 2017) which first estimate the marginal distributions and conditional on these in a second step to estimate the PVF copula parameters. Here we explore an one-stage Bayesian approach that simultaneously estimates the marginal and the PVF copula parameters. For the marginal distributions, we consider both parametric as well as semiparametric models. We propose a new method to simulate uniform pairs with PVF dependence structure based on conditional sampling for copulas and on numerical approximation to solve a target equation. In a simulation study, small sample properties of the Bayesian estimators are explored. We illustrate the usefulness of the methodology using data on times to appendectomy for adult twins in the Australian NH&MRC Twin registry. Parameters of the marginal distributions and the PVF copula are simultaneously estimated in a parametric as well as a semiparametric approach where the marginal distributions are modelled using Weibull and piecewise exponential distributions, respectively.     

The effect of teaching strategies on student achievement: An analysis using TALIS-PISA-link

The present study investigates the effects of different teaching strategies on student achievement using data from the so-called TALIS-PISA link created by the OECD. This is a recently developed instrument that allows for connecting data about teacher characteristics and practices collected in the TALIS (Teaching and Learning International Survey) survey with students’ academic performance measured in PISA (Programme for International Student Assessment). Our empirical strategy is based on an instrumental variable (IV) approach. Our results suggest that traditional teaching methods have a positive influence on students’ proficiency in mathematics, while the implementation of more innovative active learning strategies seem to have a negative impact on student achievement.     

Rethinking social work ethics: what is the real question? Responding to Stephen Webb's ‘Against difference and diversity in social work’

Jose J. Rethinking social work ethics: what is the real question? Responding to Stephen Webb's ‘Against difference and diversity in social work’ Int J Soc Welfare 2010: 19: 246–252 © 2009 The Author(s), Journal compilation © 2009 Blackwell Publishing Ltd and the International Journal of Social Welfare. In his recent article, Stephen Webb argued that the real question for social work ethics concerns ‘recognising the Same and of restoring the principles of equality and social justice’. This argument also included raising questions about what should be considered an appropriate philosophical basis for progressive social work ethics. In his view, social work's emancipatory potential has been blunted by overstated and philosophically ill‐informed human rights claims about difference and diversity. He suggested that French philosopher Alain Badiou offers social workers a ‘set of conceptual devices for rethinking social work ethics’. I argue that pressing his points into Badiou's philosophical mould is unlikely to lead to a progressive social work practice, let alone solve the issues identified by Webb. Badiou's philosophical pronouncements about ethics are of questionable value and offer little or no assistance to social workers seeking to establish an ethical grounding for their professional practice.     

Stochastic Measures of Network Resilience: Applications to Waterway Commodity Flows

Given the ubiquitous nature of infrastructure networks in today's society, there is a global need to understand, quantify, and plan for the resilience of these networks to disruptions. This work defines network resilience along dimensions of reliability, vulnerability, survivability, and recoverability, and quantifies network resilience as a function of component and network performance. The treatment of vulnerability and recoverability as random variables leads to stochastic measures of resilience, including time to total system restoration, time to full system service resilience, and time to a specific α% resilience. Ultimately, a means to optimize network resilience strategies is discussed, primarily through an adaption of the Copeland Score for nonparametric stochastic ranking. The measures of resilience and optimization techniques are applied to inland waterway networks, an important mode in the larger multimodal transportation network upon which we rely for the flow of commodities. We provide a case study analyzing and planning for the resilience of commodity flows along the Mississippi River Navigation System to illustrate the usefulness of the proposed metrics.     

A generalization of an identity of hoeffding and some applications

Summary We generalize a well-known identity due to Hoeffding and use this generalization to prove a result of Cambanis, Simons and Stout under somewhat different hypotheses and to extend some results of Lehmann concerning bivariate distributions with quadrant dependence.     

A meta-analysis of infants’ word-form recognition

Recognizing word forms is an important step on infants’ way toward mastering their native language. The present study takes a meta-analytic approach to assess overarching questions on the literature of early word-form recognition. Specifically, we investigated the extent to which there is cross-linguistic evidence for an early recognition lexicon, and how it may be influenced by infant age, language background, and familiarity of the selected stimuli (approximated by parent-reported word knowledge). Our meta-analysis—with open data access on metalab.stanford.edu—was based on 32 experiments in 16 different published or unpublished studies on infants 5–15 months of age. We found an overall significant effect of word-form familiarity on infants’ responses. This effect increased with age and was higher for infants learning Romance languages than other languages. We further found that younger, but not older, infants showed higher effect sizes for more familiar word lists. These insights should help researchers plan future studies on word-form recognition.     

Does Premarital Cohabitation Predict Subsequent Marital Stability and Marital Quality? A Meta‐Analysis

Cohabitation with a romantic partner has become common in recent decades. This meta‐analysis examined the link between premarital cohabitation and marital stability ( k = 16) and marital quality ( k = 12). Cohabitation had a significant negative association with both marital stability and marital quality. The negative predictive effect on marital stability, however, did not remain when only cohabitation with the eventual marital partner was analyzed, suggesting that these cohabitors may attach more long‐term meaning to living together. Moderator analyses demonstrated that effects of cohabitation have remained consistent over time, despite the fact that cohabitation has become more normative.