Estimation of the Sobol indices in a linear functional multidimensional model

We consider a functional linear model where the explicative variables are known stochastic processes taking values in a Hilbert space, the main example is given by Gaussian processes in L²([0,1])${\mathbb{L}}^2([0,1])$. We propose estimators of the Sobol indices in this functional linear model. Our estimators are based on U-statistics. We prove the asymptotic normality and the efficiency of our estimators and we compare them from a theoretical and practical point of view with classical estimators of Sobol indices.     

Social Network and Wage: Evidence from Cameroon

Using Cameroonian data, this paper investigates the effects of social network on wage. Social network is measured in terms of using friends and relatives while looking for a job. In order to evaluate the effectiveness of social network with regard to wage, we make use of Heckman selection model. Our findings contrast with previous studies. After factoring the endogeneity and sample selection, we find that Job seekers who make use of social network exhibit a wage premium of 1.53 per cent of average wage. We also find that social network contributes to explain wage differential according to gender and institutional sectors (formal versus informal).     

ERRATA CORRIGE: “ARE MUSLIM IMMIGRANTS DIFFERENT IN TERMS OF CULTURAL INTEGRATION?”

We are thankful to Michael Lundholm and Mahmood Arai for pointing us towards a coding error which invalidates the regressions in our paper. Correcting the code leads to a decrease in sample sizes, though much smaller than Arai et al. (2011) claim based on their “replication”. An appropriate redefinition of the variables and of the model specification allows us to reproduce the substance of the empirical analysis in our original published paper. Although the results are now less clear‐cut, our analysis remains essentially unchanged.     

Dynamic stochastic dominance in bandit decision problems

The aim of this paper is to study the monotonicity properties with respect to the probability distribution of the state processes, of optimal decisions in bandit decision problems. Orderings of dynamic discrete projects are provided by extending the notion of stochastic dominance to stochastic processes.     

Sexual Orientation and Wage Discrimination in France: The Hidden Side of the Rainbow

This article is the first study to present an econometric evaluation of wage discrimination based on sexual orientation in the French labor market. Having identified same-sex couples using the French Employment Survey, we estimate the wage gap related to sexual orientation in the private and public sectors, in order to analyze whether or not lesbians and gays suffer a wage penalty. The results obtained show the existence of a wage penalty for homosexual male workers, as compared with their heterosexual counterparts, in both the private and public sectors; the magnitude of this discrimination varies from about ?6.5?% in the private sector, to ?5.5?% in the public sector. In the private sector, the wage penalty suffered by gay employees is higher for skilled workers than for the unskilled, and??in both sectors??the wage penalty is higher for older workers than for younger ones. As with many other countries, we do not find any evidence of the existence of a wage discrimination against lesbians.     

Nest design in a changing world: Great tit <Emphasis Type="Italic">Parus major</Emphasis> nests from a Mediterranean city environment as a case study

Investigations of urbanization effects on birds have focused mainly on breeding traits expressed after the nest-building stage (e.g. first-egg date, clutch size, breeding success, and offspring characteristics). Urban studies largely ignored how and why the aspects of nest building might be associated with the degree of urbanization. As urban environments are expected to present novel environmental changes relative to rural environments, it is important to evaluate how nest-building behavior is impacted by vegetation modifications associated with urbanization. To examine nest design in a Mediterranean city environment, we allowed urban great tits (Parus major) to breed in nest boxes in areas that differed in local vegetation cover. We found that different measures of nest size or mass were not associated with vegetation cover. In particular, nests located adjacent to streets with lower vegetation cover were not smaller or lighter than nests in parks with higher vegetation cover. Nests adjacent to streets contained more pine needles than nests in parks. In addition, in nests adjacent to streets, nests from boxes attached to pine trees contained more pine needles than nests from boxes attached to other trees. We suggest that urban-related alterations in vegetation cover do not directly impose physical limits on nest size in species that are opportunistic in the selection of nesting material. However, nest composition as reflected in the use of pine needles was clearly affected by habitat type and the planted tree species present, which implies that rapid habitat change impacts nest composition. We do not exclude that urbanization might impact other aspects of nest building behaviour not covered in our study (e.g. costs of searching for nest material), and that the strengths of the associations between urbanization and nest structures might differ among study populations or species.     

Risk Communication,Values Clarification,and Vaccination Decisions

Many health‐related decisions require choosing between two options, each with risks and benefits. When presented with such tradeoffs, people often make choices that fail to align with scientific evidence or with their own values. This study tested whether risk communication and values clarification methods could help parents and guardians make evidence‐based, values‐congruent decisions about children's influenza vaccinations. In 2013–2014 we conducted an online 2×2 factorial experiment in which a diverse sample of U.S. parents and guardians (n = 407) were randomly assigned to view either standard information about influenza vaccines or risk communication using absolute and incremental risk formats. Participants were then either presented or not presented with an interactive values clarification interface with constrained sliders and dynamic visual feedback. Participants randomized to the risk communication condition combined with the values clarification interface were more likely to indicate intentions to vaccinate (β = 2.10, t(399) = 2.63, p < 0.01). The effect was particularly notable among participants who had previously demonstrated less interest in having their children vaccinated against influenza (β = –2.14, t(399) = –2.06, p < 0.05). When assessing vaccination status reported by participants who agreed to participate in a follow‐up study six months later (n = 116), vaccination intentions significantly predicted vaccination status (OR = 1.66, 95%CI (1.13, 2.44), p < 0.05) and rates of informed choice (OR = 1.51, 95%CI (1.07, 2.13), p < 0.012), although there were no direct effects of experimental factors on vaccination rates. Qualitative analysis suggested that logistical barriers impeded immunization rates. Risk communication and values clarification methods may contribute to increased vaccination intentions, which may, in turn, predict vaccination status if logistical barriers are also addressed.     

The contribution of the clean development mechanism to national climate policies

The clean development mechanism (CDM), one of the flexible mechanisms of the Kyoto Protocol, has not received noticeable attention in the applied modeling literature. In this paper we develop a policy-oriented trading model explicitly including the key features likely to influence the supply and demand of CDM projects. This model allows us to evaluate the contribution of the CDM to climate policies at the national level. With an application to Belgium we show that the CDM could reduce the cost of the Kyoto Protocol by a factor 10. Policy analyses reveal that some features (e.g. the market share) have much more influence on this result than others (notably the transaction costs). Moreover, equilibrium effects can sometimes exceed direct effects so that, all in all, a larger domestic abatement could be justified by the desire to reduce what we call carbon dependence. Policy implications and perspectives for the CDM are discussed.     

The penalized biclustering model and related algorithms

Biclustering is the simultaneous clustering of two related dimensions, for example, of individuals and features, or genes and experimental conditions. Very few statistical models for biclustering have been proposed in the literature. Instead, most of the research has focused on algorithms to find biclusters. The models underlying them have not received much attention. Hence, very little is known about the adequacy and limitations of the models and the efficiency of the algorithms. In this work, we shed light on associated statistical models behind the algorithms. This allows us to generalize most of the known popular biclustering techniques, and to justify, and many times improve on, the algorithms used to find the biclusters. It turns out that most of the known techniques have a hidden Bayesian flavor. Therefore, we adopt a Bayesian framework to model biclustering. We propose a measure of biclustering complexity (number of biclusters and overlapping) through a penalized plaid model, and present a suitable version of the deviance information criterion to choose the number of biclusters, a problem that has not been adequately addressed yet. Our ideas are motivated by the analysis of gene expression data.