Tail-weighted measures of dependence

Multivariate copula models are commonly used in place of Gaussian dependence models when plots of the data suggest tail dependence and tail asymmetry. In these cases, it is useful to have simple statistics to summarize the strength of dependence in different joint tails. Measures of monotone association such as Kendall's tau and Spearman's rho are insufficient to distinguish commonly used parametric bivariate families with different tail properties. We propose lower and upper tail-weighted bivariate measures of dependence as additional scalar measures to distinguish bivariate copulas with roughly the same overall monotone dependence. These measures allow the efficient estimation of strength of dependence in the joint tails and can be used as a guide for selection of bivariate linking copulas in vine and factor models as well as for assessing the adequacy of fit of multivariate copula models. We apply the tail-weighted measures of dependence to a financial data set and show that the measures better discriminate models with different tail properties compared to commonly used risk measures – the portfolio value-at-risk and conditional tail expectation.     

Household Saving in the United States: Measurement and Behavior

Official measures of U.S. personal saving incorporate conceptual errors relating to the measurement of both income and consumption. This article identifies the errors, computes an adjusted personal saving rate to correct the errors, and estimates equations explaining personal saving. The estimates support the adjustments, and the adjusted series has more pronounced movements than the official series, the movements being largely related to changes in income and wealth.     

Stress and Performance Standards: A Dynamic Approach to Time Spent in Housework

Daily logs collected over a 10‐week period from a small, nonrepresentative sample of young, childless married couples were examined. Housework was conceptualized as a daily decision predicated upon personal standards, social rhythms, and stress variables that shape the perception of need for housework. Findings indicate that home‐based stress, stress from outside the home, and standards are independent, additive predictors of housework time. In addition, stress and standards interact in ways suggesting that stress modifies the meaning of performance. High home‐based stress and low imported stress lead to more critical evaluations of ones' own performance and more monitoring of one's spouse's contributions. Husbands do more when wives do more, but only when wives import little stress from outside the home or perceive high demand for housework. Results are interpreted in terms of patterns of meaning and obligation.     

The emergence of social assistance in China

This article outlines the development of China's social assistance programme, including its design, implementation and trends. The Chinese government has given high priority to the establishment and institutionalisation of this programme. To have an effective social assistance programme in the context of an increasingly pluralistic society, China is facing the profoundly challenging task of designing a coherent and over-arching social protection system that would cover retirement, medical care, unemployment and poverty alleviation.     

Separation of survival and movement rates in multi-state tag-return and capture-recapture models

There has been growing interest in the estimation of transition probabilities among stages (Hestbeck et al. , 1991; Brownie et al. , 1993; Schwarz et al. , 1993) in tag-return and capture-recapture models. This has been driven by the increasing interest in meta-population models in ecology and the need for parameter estimates to use in these models. These transition probabilities are composed of survival and movement rates, which can only be estimated separately when an additional assumption is made (Brownie et al. , 1993). Brownie et al. (1993) assumed that movement occurs at the end of the interval between time i and i + 1. We generalize this work to allow different movement patterns in the interval for multiple tag-recovery and capture-recapture experiments. The time of movement is a random variable with a known distribution. The model formulations can be viewed as matrix extensions to the model formulations of single open population capturerecapture and tag-recovery experiments (Jolly, 1965; Seber, 1965; Brownie et al. , 1985). We also present the results of a small simulation study for the tag-return model when movement time follows a beta distribution, and later another simulation study for the capture-recapture model when movement time follows a uniform distribution. The simulation studies use a modified program SURVIV (White, 1983). The Relative Standard Errors (RSEs) of estimates according to high and low movement rates are presented. We show there are strong correlations between movement and survival estimates in the case that the movement rate is high. We also show that estimators of movement rates to different areas and estimators of survival rates in different areas have substantial correlations.     

Assessing perceived value: moderating effects of susceptibility to brand prestige and susceptibility to normative influence

Concerns about individuals’ susceptibility to brand prestige and their social implications of consumption often affect consumer behavior. To clarify such concerns in depth, this study assesses the relationship between brand credibility and perceived value by simultaneously examining the main effects and moderating effects of both susceptibility to brand prestige and susceptibility to normative influence. Empirical testing using a survey of 336 smartphone users from the high-tech and banking industries confirms most of the hypothesized effects in this study. Finally, based on its findings, this study discusses managerial implications as well as research limitations.     

Latinos/as and White Racial Frame: The Procrustean Bed of Assimilation

When North American slavery was established in the 1600s, an interpretive perspective was developed that sought to justify the institution of African American slavery. This composite perspective, a "white racial frame," was later extended by whites to other racial groups such as Latinos/as. This racial frame, which has become white "common sense," includes important racial stereotypes, understandings, images, and inclinations to act. Various forms of this racial framing exist among different U.S. racial groups, but a strong white racial frame has prevailed because whites have long had the power and the resources to impose this reality. A hegemonic situation occurs when people of color consent in various ways to this white racial framing and common sense. This acceptance varies. We discuss four forms of consent to white racial framing that appear in our in-depth interviews in a national sample of Latinos/as. Three forms reference Latinos: acceptance of elements of the racial frame, active enactment of the racial frame, and internalized violence. The fourth use of racial framing is directed by Latinos at African Americans.     

Sensitivity analysis for unmeasured confounding in a marginal structural Cox proportional hazards model

Sensitivity analysis for unmeasured confounding should be reported more often, especially in observational studies. In the standard Cox proportional hazards model, this requires substantial assumptions and can be computationally difficult. The marginal structural Cox proportional hazards model (Cox proportional hazards MSM) with inverse probability weighting has several advantages compared to the standard Cox model, including situations with only one assessment of exposure (point exposure) and time-independent confounders. We describe how simple computations provide sensitivity for unmeasured confounding in a Cox proportional hazards MSM with point exposure. This is achieved by translating the general framework for sensitivity analysis for MSMs by Robins and colleagues to survival time data. Instead of bias-corrected observations, we correct the hazard rate to adjust for a specified amount of unmeasured confounding. As an additional bonus, the Cox proportional hazards MSM is robust against bias from differential loss to follow-up. As an illustration, the Cox proportional hazards MSM was applied in a reanalysis of the association between smoking and depression in a population-based cohort of Norwegian adults. The association was moderately sensitive for unmeasured confounding.     

Community-based organizations - new fad or old hat?

Globally, we are witnessing a renewed interest in the role ofMembership Based Organizations in improving the livelihoodsof poor people. This reflection reports on an internationalconference in which academics and practitioners came togetherto discuss the significance of these developments. Unusuallythe conference was preceded by a period in which participantslived with poor members of the conference organizers. This livedexperience complemented the more abstract papers presented atthe conference. Crucially however it also drew attention tothe serious challenge of supporting organizational attemptsto bring about transformative as opposed to cosmetic change.