Frequency of Selecting Noise Variables in Subset Regression Analysis: A Simulation Study

This article presents the results of a simulation study of variable selection in a multiple regression context that evaluates the frequency of selecting noise variables and the bias of the adjusted R ² of the selected variables when some of the candidate variables are authentic. It is demonstrated that for most samples a large percentage of the selected variables is noise, particularly when the number of candidate variables is large relative to the number of observations. The adjusted R ² of the selected variables is highly inflated.     

The marked empirical process to test nonlinear time series against a large class of alternatives when the random vectors are nonstationary and absolutely regular

In this paper, we propose a method for testing absolutely regular and possibly nonstationary nonlinear time-series, with application to general AR-ARCH models. Our test statistic is based on a marked empirical process of residuals which is shown to converge to a Gaussian process with respect to the Skohorod topology. This testing procedure was first introduced by Stute [Nonparametric model checks for regression, Ann. Statist. 25 (1997), pp. 613–641] and then widely developed by Ngatchou-Wandji [Weak convergence of some marked empirical processes: Application to testing heteroscedasticity, J. Nonparametr. Stat. 14 (2002), pp. 325–339; Checking nonlinear heteroscedastic time series models, J. Statist. Plann. Inference 133 (2005), pp. 33–68; Local power of a Cramer-von Mises type test for parametric autoregressive models of order one, Compt. Math. Appl. 56(4) (2008), pp. 918–929] under more general conditions. Applications to general AR-ARCH models are given.     

Work Trajectories of Female and Male Immigrants in Spain

This article aims to examine in depth the work trajectories of individuals over time, in order to provide a wider perspective of the employment history of immigrants compared to native people, by gender and for more than one decade (2005–2017) in Spain. We use microdata (cohort and multivariate analysis) from the Labour Force Survey and carry out a comparison for three groups: the Spanish born in Spain, the Spanish born abroad, and the non-Spanish born abroad. The results confirm that the non-Spanish born-abroad group is characterized by the existence of segmented assimilation. All foreigners suffered a loss in their work trajectories, since their employment rate in 2017 has as yet neither reached the level of the last years of the previous economic expansion nor the level of the previous cohorts at the same age.     

Conceptualising social capital in relation to the well-being of children and young people: a critical review

This exploratory article forms the background for an empirical study for the Health Education Authority on children, young people, health, well-being and social capital. In terms of morbidity, children tend not to exhibit clear health problems, but obviously engage in activities that have important implications for their health and well-being (West & Sweeting, 1996), and these activities may be influenced by, as well as impact upon, children's social capital. Social capital is an elusive concept and has been defined in various ways, and refers to sociability, social networks and social support, trust, reciprocity, and community and civic engagement. The paper contrasts three interpretations of the concept, by Coleman (1988, 1990), Putnam (1993, 1995) and Bourdieu (1986). It concludes that the concept is currently poorly specified as it relates to children, and that the use of the term is inherently problematic, and needs to be carefully critiqued and empirically grounded before it can usefully be applied in social policy formulations. One possible way forward might be to conceptualise social capital not so much as a measurable ‘thing’, rather as a set of processes and practices that are integral to the acquisition of other forms of ‘capital’ such as human capital and cultural capital (ie qualifications, skills, group memberships, etc).     

Secular declines in the association between obesity and mortality in the United States

Recent research suggests that rising obesity will restrain future gains in US life expectancy and that obesity is an important contributor to the current shortfall in us longevity compared to other high-income countries. Estimates of the contribution of obesity to current and future national-level mortality patterns are sensitive to estimates of the magnitude of the association between obesity and mortality at the individual level. We assessed secular trends in the obesity/mortality association among cohorts of middle-aged adults between 1948 and 2006 using three long-running US data sources: the Framingham Heart Study, the National Health and Nutrition Examination Survey, and the National Health Interview Survey. We find substantial declines over time in the magnitude of the association between obesity and overall mortality and, in certain instances, cardiovascular-specific mortality. We conclude that estimates of the contribution of obesity to current national-level mortality patterns should take into account recent reductions in the magnitude of the obesity and mortality association.     

Discrimination Hurts: The Academic,Psychological, and Physical Well‐Being of Adolescents

Little is known about the frequency of ethnic or racial discrimination and its implications for Latin American and Asian youths' development. In this study, we examined if there were ethnic and generation differences among 601 12th graders from Latin American (36%), Asian (43%), and European (19%) backgrounds in the frequency of peer, adult, and daily discrimination, and whether discrimination predicted their well‐being. Adolescents from Latin American and Asian backgrounds reported more adult and peer discrimination than their peers from European backgrounds. Latin American youth reported more adult discrimination than their Asian peers. Discrimination predicted lower grade point averages and self‐esteem, and more depressive symptoms, distress, and physical complaints. Ethnic identity, ethnic socialization, and race rejection sensitivity did not moderate the associations between discrimination and well‐being.     

Decreasing higher-order absolute risk aversion and higher-degree stochastic dominance

Fishburn and Vickson (Stochastic dominance: an approach to decision-making under risk, Lexington Books, D.C. Heath and Company, Lexington, pp. 39–113, 1978) showed that, when applied to random alternatives with an equal mean, 3rd-degree and decreasing absolute risk aversion stochastic dominances represent equivalent rules. The present paper generalizes this result to higher degrees. Specifically, higher-degree stochastic dominance rules and common preference by all decision makers with decreasing higher-order absolute risk aversion are shown to coincide under appropriate constraints on the respective moments of the random variables to be compared.     

Benchmark values for higher order coefficients of relative risk aversion

The existing literature on savings, insurance, and portfolio choices under risk has revealed that quite often comparative statics results depend, among other things, upon the values of the coefficients of relative risk aversion and relative prudence. More specifically the benchmark values for these coefficients are, respectively, one and two. Recently, several papers investigated constraints on the higher degree extensions of the coefficients of relative risk aversion and of relative prudence. The present work provides a unified approach to this question based on the concept of elementary correlation increasing transformations, allowing for a better understanding of changes in risk in the multiplicative case.