Beyond tail median and conditional tail expectation: Extreme risk estimation using tail Lp-optimization

The conditional tail expectation (CTE) is an indicator of tail behavior that takes into account both the frequency and magnitude of a tail event. However, the asymptotic normality of its empirical estimator requires that the underlying distribution possess a finite variance; this can be a strong restriction in actuarial and financial applications. A valuable alternative is the median shortfall (MS), although it only gives information about the frequency of a tail event. We construct a class of tail L^p-medians encompassing the MS and CTE. For p in (1,2), a tail L^p-median depends on both the frequency and magnitude of tail events, and its empirical estimator is, within the range of the data, asymptotically normal under a condition weaker than a finite variance. We extrapolate this estimator and another technique to extreme levels using the heavy-tailed framework. The estimators are showcased on a simulation study and on real fire insurance data.     

CORRUPTION: TOP DOWN OR BOTTOM UP?

This article studies the impact of corruption on an economy with a hierarchical government. In particular, we study whether centralizing corruption within the higher level of government increases or decreases the total amount of corruption. We show that when the after-tax relative profitability of the formal sector as compared to that of the informal sector is high enough, adding a layer of government increases the total amount of corruption. By contrast, for high-enough public wages and/or an efficient monitoring technology of the bureaucratic system, centralization of corruption at the top of the government hierarchy redistributes bribe income from the lower level to the upper level. In the process, total corruption is reduced and the formal sector of the economy expands.     

Catalogue of Group Structures for Three-level Fractional Factorial Designs

Taguchi (1959) introduced the concept of split-unit design to sort the factors into different groups depending upon the difficulties involved in changing the levels of factors. Li et al. (1991) renamed it as split-plot design. Chen et al. (1993) have given a catalogue of small designs for two- and three-level fractional factorial designs pertaining to a single type of factors. Aggarwal et al. (1997) have given a catalogue of group structure for two-level fractional factorial designs developed under the concept of split-plot design. In this paper, an algorithm has been developed for generating group structure and possible allocations for various 3^n-k fractional factorial designs.     

Job displacement effects of Canadian immigrants by country of origin and occupation

"Some previous Canadian studies have shown that considering the labor market as a whole and also pooling all immigrants as a group, immigrants do not have any job displacement effects on the Canadian born. This study presents some new evidence. It disaggregates immigrants by country of origin and by occupation groups and provides an analysis of job displacement effects of immigrants on the native-born Canadians by these dimensions. The study finds that (1) U.S. immigrants and the Canadians are substitutes [for] competing groups in the labor market and the effect is quite significant; (2) Canadians and Europeans are competing groups in certain occupations, while they have complementary skills in others; and (3) immigrants from the Third World and the Canadians are slightly competing groups in certain occupations."     

Toddlers Help Anonymously

Young children are extremely motivated to help others, but it is not clear whether they do so in anonymous situations without social recognition. In two studies, we found that 18‐month‐old toddlers provided help equally in situations where an adult recipient was present and in situations where an adult recipient was not present. We included several control conditions to rule out that toddlers were simply unaware of their anonymity or were merely motivated to restore the physical order of things. Together, these findings suggest that early in ontogeny children are motivated to help others in need regardless of whether they can immediately be recognized for their prosocial intentions.     

Adult Sexual Outcomes of Child Sexual Abuse Vary According to Relationship Status

This study tested a moderation model in which the association between child sexual abuse severity and negative sexual outcomes (i.e., sexual avoidance and compulsivity) differed as a function of relationships status (i.e., single, cohabiting, and married individuals). A sample of 1,033 adults completed self‐report questionnaires online, and 21.5% reported childhood sexual abuse. Path analyses indicated that child sexual abuse severity was associated with higher sexual compulsivity in single individuals, both higher sexual avoidance and compulsivity in cohabiting individuals, and higher sexual avoidance in married individuals. The moderation model was invariant across men and women. These results suggest that the time course of negative sexual outcomes associated with child sexual abuse may follow distinct patterns of expression according to relationship status.     

“Phil's Calling Grandma… ”: The Role of External Support in Human–Companion Animal Identity Pairings

This exploratory paper deals with human–animal role identity pairings such as parent–child or sibling–sibling and the necessity of support from other actors both for the formation of these idiosyncratic identities, as well as for their situational placement in social environments not limited to the nonhuman animal. Taken from a qualitative study examining identity formation counter to the nonhuman animal, I use in‐depth interviews of both people with and without human children to demonstrate how human‐to‐human relationships are formed by categorizing the companion animal as a “child” of sorts within the family structure. These relationships prove integral to the continued development and enactment of identities such as the animal “parent” or the animal “sibling” via three different groups: their own parents, partners, and, in one case, adult siblings. This creates positive affect and commitment to the identity across other social situations. Implications of these findings for identity theory and family research are discussed.     

A Network-Based Measure of the Socio-Economic Roots of the Migration Flows

Social Indicators Research - This paper provides a unified view for defining a measure of the reasons behind migration flows whose nature is of social and economic type. To this aim, worldwide...     

A new algorithm to estimate monotone nonparametric link functions and a comparison with parametric approach

The generalized linear model (GLM) is a class of regression models where the means of the response variables and the linear predictors are joined through a link function. Standard GLM assumes the link function is fixed, and one can form more flexible GLM by either estimating the flexible link function from a parametric family of link functions or estimating it nonparametically. In this paper, we propose a new algorithm that uses P-spline for nonparametrically estimating the link function which is guaranteed to be monotone. It is equivalent to fit the generalized single index model with monotonicity constraint. We also conduct extensive simulation studies to compare our nonparametric approach for estimating link function with various parametric approaches, including traditional logit, probit and robit link functions, and two recently developed link functions, the generalized extreme value link and the symmetric power logit link. The simulation study shows that the link function estimated nonparametrically by our proposed algorithm performs well under a wide range of different true link functions and outperforms parametric approaches when they are misspecified. A real data example is used to illustrate the results.