Non‐parametric Estimation of Extreme Risk Measures from Conditional Heavy‐tailed Distributions

In this paper, we introduce a new risk measure, the so‐called conditional tail moment. It is defined as the moment of order a ≥ 0 of the loss distribution above the upper α‐quantile where α ∈ (0,1). Estimating the conditional tail moment permits us to estimate all risk measures based on conditional moments such as conditional tail expectation, conditional value at risk or conditional tail variance. Here, we focus on the estimation of these risk measures in case of extreme losses (where α ↓0 is no longer fixed). It is moreover assumed that the loss distribution is heavy tailed and depends on a covariate. The estimation method thus combines non‐parametric kernel methods with extreme‐value statistics. The asymptotic distribution of the estimators is established, and their finite‐sample behaviour is illustrated both on simulated data and on a real data set of daily rainfalls.     

A Bottom-Up Dynamic Model of Portfolio Credit Risk with Stochastic Intensities and Random Recoveries

In Bielecki et al. (2014a Bielecki , T. R. , Cousin , A. , Crépey , S. , Herbertsson , A. ( 2014a ). Dynamic hedging of portfolio credit risk in a markov copula model . J. Optimiz. Theor. Applic . doi: DOI 10.1007/s10957-013-0318-4 (forthcoming) .[Crossref] , [Google Scholar]), the authors introduced a Markov copula model of portfolio credit risk where pricing and hedging can be done in a sound theoretical and practical way. Further theoretical backgrounds and practical details are developed in Bielecki et al. (2014b Bielecki , T. R. , Cousin , A. , Crépey , S. , Herbertsson , A. ( 2014b ). A bottom-up dynamic model of portfolio credit risk - Part I: Markov copula perspective . In: Recent Adv. Fin. Eng. 2012 , World Scientific (preprint version available at http://dx.doi.org/10.2139/ssrn.1844574) . [Google Scholar],c) where numerical illustrations assumed deterministic intensities and constant recoveries. In the present paper, we show how to incorporate stochastic default intensities and random recoveries in the bottom-up modeling framework of Bielecki et al. (2014a Bielecki , T. R. , Cousin , A. , Crépey , S. , Herbertsson , A. ( 2014a ). Dynamic hedging of portfolio credit risk in a markov copula model . J. Optimiz. Theor. Applic . doi: DOI 10.1007/s10957-013-0318-4 (forthcoming) .[Crossref] , [Google Scholar]) while preserving numerical tractability. These two features are of primary importance for applications like CVA computations on credit derivatives (Assefa et al., 2011 Assefa , S. , Bielecki , T. R. , Crépey , S. , Jeanblanc , M. ( 2011 ). CVA computation for counterparty risk assessment in credit portfolios . In: Bielecki , T.R. , Brigo , D. , Patras , F. , Eds., Credit Risk Frontiers . Hoboken : Wiley/Bloomberg-Press . [Google Scholar]; Bielecki et al., 2012 Bielecki , T. R. , Crépey , S. , Jeanblanc , M. , Zargari , B. ( 2012 ). Valuation and Hedging of CDS counterparty exposure in a markov copula model . Int. J. Theoret. Appl. Fin. 15 ( 1 ): 1250004 .[Crossref] , [Google Scholar]), as CVA is sensitive to the stochastic nature of credit spreads and random recoveries allow to achieve satisfactory calibration even for “badly behaved” data sets. This article is thus a complement to Bielecki et al. (2014a Bielecki , T. R. , Cousin , A. , Crépey , S. , Herbertsson , A. ( 2014a ). Dynamic hedging of portfolio credit risk in a markov copula model . J. Optimiz. Theor. Applic . doi: DOI 10.1007/s10957-013-0318-4 (forthcoming) .[Crossref] , [Google Scholar]), Bielecki et al. (2014b Bielecki , T. R. , Cousin , A. , Crépey , S. , Herbertsson , A. ( 2014b ). A bottom-up dynamic model of portfolio credit risk - Part I: Markov copula perspective . In: Recent Adv. Fin. Eng. 2012 , World Scientific (preprint version available at http://dx.doi.org/10.2139/ssrn.1844574) . [Google Scholar]) and Bielecki et al. (2014c Bielecki , T. R. , Cousin , A. , Crépey , S. , Herbertsson , A. ( 2014c ). A bottom-up dynamic model of portfolio credit risk - Part II: Common-shock interpretation, calibration and hedging issues . Recent Adv. Fin. Eng. 2012 , World Scientific (preprint version available at http://dx.doi.org/10.2139/ssrn.2245130) . [Google Scholar]).     

Simulation/Regression Pricing Schemes for CVA Computations on CDO Tranches

We devise simulation/regression numerical schemes for pricing the CVA on CDO tranches, where CVA stands for Credit Valuation Adjustment, or price correction accounting for the defaultability of a counterparty in an OTC derivatives transaction. This is done in the setup of a continuous-time Markov chain model of default times, in which dependence between credit names is represented by the possibility of simultaneous defaults. The main idea of this article is to perform the nonlinear regressions which are used for computing conditional expectations, in the time variable for a given state of the model, rather than in the space variables at a given time in diffusive setups. This idea is formalized as a lemma which is valid in any continuous-time Markov chain model. It is then implemented on the targeted application of CVA computations on CDO tranches.     

Local influence for functional comparative calibration models with replicated data

We investigate local influence analysis in functional comparative calibration models with replicated data. A method for selecting appropriate perturbation schemes based on the expected Fisher information matrix with respect to the perturbation vector is proposed. It is shown that arbitrarily perturbing these models may result in misleading inference about the influential subjects. First-order influence measures for identifying the correct influential subjects and replicates on corrected score estimators are defined. We introduce different perturbation schemes including perturbation of subjects and replicates on the corrected likelihood function and obtain the density of the perturbed model from which the methodology is based. Particularly, three perturbation of variances schemes could be a better way to handle badly modeled subjects or replicates. Two real data sets are analyzed to illustrate the use of our local influence measures.     

Adolescent migration and the 1990s nuptiality transition in Mali

Attempts to explain the rise in women's age at marriage across Africa have focused mainly on determinants in the urban environment, notably women's education and the economic recession. In our study, we examined the migration of adolescent girls as a factor in the transition to a later age of marriage in rural Mali, using an analysis of data from a longitudinal survey conducted over 20 years. The findings show a close correlation between the rise in labour migration and the onset of this nuptiality transition. Continuing changes in marriage patterns include not only its postponement but also a breakdown in the marriage formalization process. Two main mechanisms are documented: a direct one, as migration enables young women to choose the timing of their marriage and is a source of empowerment; and an indirect one, as migration challenges family marriage conventions and contributes to elders disengaging from control over marriage and young people.     

High Sex Ratios at Birth in the Caucasus: Modern Technology to Satisfy Old Desires

During the 1990s, the sex ratio at birth increased considerably and simultaneously in the three independent Caucasian countries, Armenia, Azerbaijan, and Georgia. At the end of the first decade of the twenty‐first century, levels remain abnormally high in Armenia and Azerbaijan (above 114 male births per 100 female births) and show erratic trends in Georgia. Analyzing data from demographic surveys carried out around 2005, we confirm the persistence of high sex ratios in these three countries and document significant differences in fertility intentions and behavior according to the sex of the previous child or children that constitute evidence of the practice of sex‐selective abortion. These countries combine societal features and medical systems that make this phenomenon possible: son preference in a context of low fertility and the possibility of prenatal sex selection given easy access to ultrasound screening and induced abortion. Why high sex ratios are observed only in these three countries of the sub‐region remains, however, an open question.     

A Review Essay on the Measurement of Child Well-Being

Research on indicators related to the state of child well-being is a growing field that has experienced several changes over time. The growing supply of data on children, as well as the need to facilitate conclusions and to track trends, has led researchers to develop a number of child well-being indexes. This paper critically reviews the most recent and relevant child well-being indexes, i.e., the Index of Child and Youth Well-Being in the United States, the Child Well-being Index for the European Union, the Microdata Child Well-being Index, and the Deprivation Index. The study focuses primarily on the contributions and innovations the indexes have brought to the field, making a critical assessment of the methods used in the construction of the indexes and identifying their main limitations.     

Reconciling Work, Family and Child Outcomes: What Implications for Family Support Policies?

This paper discusses the potential of family policies to reconcile the multiple objectives that they are expected to serve, over and above their role in offsetting the economic cost of children. We start by emphasizing the need to consider the multiple challenges that family policies in European Union??and/or OECD??countries have to address through a broadening of the standard economic approach to the cost of children. Policies indeed aim to reduce the ??direct?? monetary cost of raising children, but they also aim to minimise the indirect cost arising from the incidence of children on the parents?? work-life balance and on the aggregate level of employment. Moreover, motives for policy intervention such as concerns about child development, gender equity or aggregate fertility levels are not fully captured by cost measurements. We thus analyse how, and to what extent, family policies can successfully reconcile these multidimensional objectives. We offer a holistic approach, pointing out that a coherent family policy mix supporting working parents with preschool children is the only way to reconcile or limit the conflicts between work, family and child outcomes. Three main dichotomies are identified to explain cross-country differences in family policy packages: the emphasis on poverty alleviation; the supposed antagonism between fertility and female employment; and the potential conflict between this latter and child development. Ways to reconcile these objectives and to improve the effectiveness and efficiency of family policies are further discussed.     

Subjective Welfare, Well-Being, and Self-Reported Food Hypersensitivity in Four European Countries: Implications for European Policy

This study estimates the effects of food hypersensitivity on individuals?? perceived welfare and well-being compared to non-food hypersensitive individuals. Study respondents were recruited in the Netherlands, Poland, Spain and UK. The difference in welfare between food hypersensitive respondents and those asymptomatic to foods was estimated using a subjective welfare approach, including income evaluation. Well-being was measured using the Cantril Ladder-of-Life Scale, and health status using the Self-Perceived Health Scale. The difference in well-being, welfare and health status between participant groups was explained further using a number of background variables. No significant within-country differences in welfare between food hypersensitive respondents and respondents asymptomatic to foods were found. In terms of well-being, adult food hypersensitive respondents and their spouses reported significantly less happiness than respondents and their spouses asymptomatic to foods in the Netherlands and Poland. In Spain, the spouses of the food hypersensitive respondents were significantly less happy than respondents aymptomatic to foods. The well-being of children did not significantly differ between groups. The degree of severity of food hypersensitivity was negatively related to overall health status. In Poland, food hypersensitive respondents reported worse health status compared to asymptomatic respondents. In Spain, the converse was true. Food hypersensitive respondents were generally less happy with their life as a whole than respondents asymptomatic to foods, presumably because they experienced more negative effects, which were not related to perceived health status.     

Competence effects for choices involving gains and losses

We investigate how choices for uncertain gain and loss prospects are affected by the decision maker’s perceived level of knowledge about the underlying domain of uncertainty. Specifically, we test whether Heath and Tversky’s (J Risk Uncertain 4:5–28, 1991) competence hypothesis extends from gains to losses. We predict that the commonly-observed preference for high knowledge over low knowledge prospects for gains reverses for losses. We employ an empirical setup in which participants make hypothetical choices between gain or loss prospects in which the outcome depends on whether a high or low knowledge event occurs. We infer decision weighting functions for high and low knowledge events from choices using a representative agent preference model. For gains, we replicate the results of Kilka and Weber (Manage Sci 47:1712–1726, 2001), finding that decision makers are more attracted to choices that they feel more knowledgeable about. However, for losses, we find limited support for our extension of the competence effect.