Examination and visualisation of the simplifying assumption for vine copulas in three dimensions

Vine copulas are a highly flexible class of dependence models, which are based on the decomposition of the density into bivariate building blocks. For applications one usually makes the simplifying assumption that copulas of conditional distributions are independent of the variables on which they are conditioned. However this assumption has been criticised for being too restrictive. We examine both simplified and non‐simplified vine copulas in three dimensions and investigate conceptual differences. We show and compare contour surfaces of three‐dimensional vine copula models, which prove to be much more informative than the contour lines of the bivariate marginals. Our investigation shows that non‐simplified vine copulas can exhibit arbitrarily irregular shapes, whereas simplified vine copulas appear to be smooth extrapolations of their bivariate margins to three dimensions. In addition to a variety of constructed examples, we also investigate a three‐dimensional subset of the well‐known uranium data set and visually detect the fact that a non‐simplified vine copula is necessary to capture its complex dependence structure.     

Falling through the social safety net? Analysing non-take-up of minimum income benefit and monetary social assistance in Austria

Non-take-up of means tested benefits is a widespread phenomenon in European welfare states. The paper assesses whether the reform that replaced the monetary social assistance benefit by the minimum income benefit in Austria in 2010/11 has succeeded in increasing take up rates. We use EU-SILC register data together with the tax-benefit microsimulation model EUROMOD/SORESI. The results show that the reform led to a significant decrease of non-take-up from 53 to 30% in terms of the number of households and from 51 to 30% in terms of expenditure. Following the three-t's (threshold, trigger, and trade-off) introduced by Van Oorschot, estimates of a two-stage Heckman selection model as well as expert interviews indicate that the taken measures include both threshold and trade-off characteristics. Elements such as the higher degree of anonymity within the claiming process, the provision of health insurance, binding minimum standards, the limitation of the maintenance obligations, new regulations related to the liquidation of wealth, as well as the general coverage of the benefit reform in the media and in public discussions led to an improved access to the benefit.     

Ageing of a giant: a stochastic population forecast for China, 2006–2060

This paper presents a stochastic population forecast for China with a special emphasis on population ageing. The so-called scaled model for error was used to quantify the uncertainty attached to the population predictions. Data scarcity was a major problem in the specification of the expected error of the population forecast. Therefore, the error structures estimated for European countries were used with some modifications, taking into account the large size and heterogeneity of the Chinese population. The stochastic forecast confirms the expectation of extremely rapid population ageing during the first half of the twenty-first century in China. The old age dependency ratio (OADR) will certainly increase. Simply maintaining the current demographic rates (no international migration) would drive the OADR to 0.42 in 2060, four times the current level. Including expected declines in mortality and net outmigration in the projection would increase the median OADR in 2060 to 0.59, with a 80% prediction interval of [0.47, 0.75]. In particular, the oldest-old population will grow much faster than any other age group. This development has major implications for policy-making in China.

Measuring the Immeasurables: Development and Initial Validation of the Self-Other Four Immeasurables (SOFI) Scale Based on Buddhist Teachings on Loving Kindness,Compassion, Joy,and Equanimity

Multiple measures exist that examine the attentional aspects of meditation practice, but measurement of the compassion component is relatively understudied. This paper describes the development and initial validation of a scale designed to measure application of the four immeasurable qualities at the heart of Buddhist teachings: loving kindness, compassion, joy and acceptance toward both self and others. Our analyses suggest four distinct subscales: positive qualities toward self, positive qualities toward others, negative qualities toward self and negative qualities toward others. Initial examination of reliability and validity showed high internal consistency for the subscales as well as strong concurrent, discriminant, and construct validity. We believe the Self-Other Four Immeasurables (SOFI) scale has broad utility for research on mindfulness, positive psychology, and social psychology.     

USE OF EXPERT RATINGS AS SAMPLING STRATA FOR A MORE COST-EFFECTIVE PROBABILITY SAMPLE OF A RARE POPULATION

We consider situations in which externally observable characteristics allow experts to quickly categorize individual households as likely or unlikely to contain a member of a rare target population. This classification can form the basis of disproportionate stratified sampling such that households classified as "unlikely" are sampled at a lower rate than those classified as "likely," thereby reducing screening costs. Design weights account for this approach and allow unbiased estimates for the target population.We demonstrate that with sensitivity and specificity of expert classification at least 70%, and ideally at least 80%, our approach can economically increase effective sample size for a rare population. We develop heuristics for implementing this approach and demonstrate that sensitivity drives design effects and screening costs whereas specificity only drives the latter. We demonstrate that the potential gains from this approach increase as the target population becomes rarer. We further show that for most applications, unlikely strata should be sampled at 1/6 to ? the rate of likely strata.This approach was applied to a survey of Cambodian immigrants in which the 82% of households rated "unlikely" were sampled at ? the rate as "likely" households, reducing screening from 9.4 to 4.0 approaches per complete. Sensitivity and specificity were 86% and 91% respectively. Weighted estimation had a design effect of 1.26 so screening costs per effective sample size were reduced 47%. We also note that in this instance, expert classification appeared to be uncorrelated with survey outcomes of interest among eligibles.     

Die Umzugsentscheidung von Paaren als Verhandlungsproblem

Recently bargaining models became a popular theoretical concept within family research. Especially compared to household economic theory, bargaining models are less abstract and provide a tool for analysis of conflicting interests and their consequences in family relationships. However, although there are many different topics which can be tackled with this kind of theory, there is still a lack of direct empirical tests concerning this concept. The aim of this article is to provide such a test by using a special type of a quasi-experimental research design. With a so-called factorial design we vary systematically incentives for a household move in order to model different structural conditions of a relationship like earning possibilities or chances for a career of a partner. This allows us to observe varying power allocations within the relationship. The empirical results support the hypotheses derived from the bargaining model: the respondent anticipates a loss of his or her bargaining power as well as an increasing power of the partner. Consequently they answer such a change with a reduced tendency for a household move and a higher perceived potential for conflicts within the relationship. However, due to our limited knowledge about the validity of the quasi-experimental design these results need to be validated by future research.     

Cognitive Components of Risk Ratings

This study examined what lay people mean when they judge the "risk" of activities that involve the potential for accidental fatalities (e.g., hang gliding, living near a nuclear reactor). A sample of German and American students rated the "overall risk" of 14 such activities and provided 3 fatality estimates: the number of fatalities in an "average year," the individual yearly fatality probability (or odds), and the number of fatalities in a "disastrous accident." Subjects' fatality estimates were reasonably accurate and only moderately influenced by attitudes towards nuclear energy. Individual fatality probability correlated most highly with intuitive risk ratings. Disaster estimates correlated positively with risk ratings for those activities that had a low fatality probability and a relatively high disaster potential. Annual average fatality rates did not correlate with risk ratings at all. These findings were interpreted in terms of a two-dimensional cognitive structure. Subjective notions of risk were determined primarily by the personal chance of death; for some activities, "disaster potential" played a secondary role in shaping risk perception.     

Data-driven smooth tests of the proportional hazards assumption

A new test of the proportional hazards assumption in the Cox model is proposed. The idea is based on Neyman’s smooth tests. The Cox model with proportional hazards (i.e. time-constant covariate effects) is embedded in a model with a smoothly time-varying covariate effect that is expressed as a combination of some basis functions (e.g., Legendre polynomials, cosines). Then the smooth test is the score test for significance of these artificial covariates. Furthermore, we apply a modification of Schwarz’s selection rule to choosing the dimension of the smooth model (the number of the basis functions). The score test is then used in the selected model. In a simulation study, we compare the proposed tests with standard tests based on the score process.     

The Relationship of Four Types of ‘Broken Home’ to Some Neglected Parameters of Juvenile Delinquency

Using a sample of 1,130 male juvenile offenders, the relationship of four types of ‘broken home’ to the age at onset of delinquency, recidivism, rate of offences, and types of offence was investigated. The number of recidivists was found to be significantly greater among offenders who were living only with fathers than among offenders living with both parents. A trend in this direction was also found among offenders living only with mothers. Offenders living apart from parents were found to be older at the time of their first offence than were offenders living with both parents. The findings were discussed critically, and it was concluded that they support the hypothesis that the ‘broken home’ is not per se a causal factor in juvenile delinquency.     

A parsimonious multivariate poisson model for market basket analysis

Intensified research on multivariate Poisson models offers new opportunities for the analysis of purchase quantities in market basket data. The investigation of positive or negative correlations in quantity decisions among product categories facilitates a deeper understanding of consumer purchase behavior. The applied multivariate log-normal Poisson model introduces interdependencies between categories with multivariate normal-distributed latent effects by means of a covariance matrix. As the size of this covariance matrix depends on the number of categories in the model, its ation may become tedious. Furthermore, we assume that quantity decisions do not interact for all pairs of categories. That is why we propose to use covariance selection to derive a parsimonious representation of the correlation structure. For two market basket data sets, we show that the vast majority of off-diagonal elements in the covariance matrix are irrelevant. For a data set with product categories, the model with a partly restricted covariance matrix achieves a better fit to the holdout data than the model with full covariance matrix. For a data set with subcategories of the broader category beverage, the proposed model with restricted covariance outperforms the model with full covariance matrix even on the calibration data. We conclude that interactions of quantity decisions are overall the exception, even for complements-in-use.