A psychosocial study on crime and gender: Position,role and status of women in a sample of Spanish criminal organizations / Un estudio psicosocial sobre la delincuencia y género. Posición,rol y estatus de la mujer en una muestra española de organizaciones criminales

The purpose of this study was to determine the socio-demographic characteristics of a sample of females (N = 200) who have belonged to organized crime groups (N = 67) that have operated in Spain between 1999 and 2010, along with what their roles and status have been. The information has been mined from police records provided by the Central Operational Unit of the Guardia Civil. The results enable us to conclude that most of the females are adults, and that many of them have family or partner ties to the organizations. Furthermore, they are actively involved in these criminal groups, mainly performing jobs that do not require the use of violence, and they are especially needed for internal security. In terms of status, the majority seem to be at the lowest level of the organizational structure, although we have managed to identify some women who have played leadership roles in criminal organizations.     

Education and Roma Children in the Basque Region of Spain

The European Union and those countries that make up the region of South-eastern Europe are built on the pillars of a multicultural society, with different languages, cultures, religions and ethnic groups. This diversity gives rise to various kinds of conflicts. The way in which we resolve these will determine the kind of future we can create for next generations. In this paper, we look at the situation of Roma and Educational provisions for Roma in the Basque region of Spain. It is clear that improvements are being made, but that much work is still necessary. Too few Roma children succeed at the moment in the Spanish and Basque educational systems. We use the case study of one school, the La Esperanza School, to highlight opportunities and barriers to effectively addressing the issue of Roma education.     

Statistical control charts for shifted generalized poisson distribution

Summary The use of shifted (or zero-truncated) generalized Poisson distribution to describe the occurrence of events in production processes is considered. The methods of moments and maximum likelihood are proposed for estimating the parameters of shifted generalized Poisson distribution. Control charts for the total number of events and for the average number of events are developed. Finally, a numerical example is used to illustrate the construction of control charts.     

A computational analysis of the tournament equilibrium set

A recurring theme in the mathematical social sciences is how to select the “most desirable” elements given a binary dominance relation on a set of alternatives. Schwartz’s tournament equilibrium set (TEQ) ranks among the most intriguing, but also among the most enigmatic, tournament solutions proposed so far. Due to its unwieldy recursive definition, little is known about TEQ. In particular, its monotonicity remains an open problem to date. Yet, if TEQ were to satisfy monotonicity, it would be a very attractive solution concept refining both the Banks set and Dutta’s minimal covering set. We show that the problem of deciding whether a given alternative is contained in TEQ is NP-hard, and thus does not admit a polynomial-time algorithm unless P equals NP. Furthermore, we propose a heuristic that significantly outperforms the naive algorithm for computing TEQ.     

Marginalized zero-inflated generalized Poisson regression

The generalized Poisson (GP) regression model has been used to model count data that exhibit over-dispersion or under-dispersion. The zero-inflated GP (ZIGP) regression model can additionally handle count data characterized by many zeros. However, the parameters of ZIGP model cannot easily be used for inference on overall exposure effects. In order to address this problem, a marginalized ZIGP is proposed to directly model the population marginal mean count. The parameters of the marginalized zero-inflated GP model are estimated by the method of maximum likelihood. The regression model is illustrated by three real-life data sets.     

On the bivariate negative binomial regression model

In this paper, a new bivariate negative binomial regression (BNBR) model allowing any type of correlation is defined and studied. The marginal means of the bivariate model are functions of the explanatory variables. The parameters of the bivariate regression model are estimated by using the maximum likelihood method. Some test statistics including goodness-of-fit are discussed. Two numerical data sets are used to illustrate the techniques. The BNBR model tends to perform better than the bivariate Poisson regression model, but compares well with the bivariate Poisson log-normal regression model.     

Approximate Generalizations and Computational Experiments

In this paper I demonstrate how one can generalize finitely many examples to statements about (infinite) classes of economic models. If there exist upper bounds on the number of connected components of one‐dimensional linear subsets of the set of parameters for which a conjecture is true, one can conclude that it is correct for all parameter values in the class considered, except for a small residual set, once one has verified the conjecture for a predetermined finite set of points. I show how to apply this insight to computational experiments and spell out assumptions on the economic fundamentals that ensure that the necessary bounds on the number of connected components exist. I argue that these methods can be fruitfully utilized in applied general equilibrium analysis. I provide general assumptions on preferences and production sets that ensure that economic conjectures define sets with a bounded number of connected components. Using the theoretical results, I give an example of how one can explore qualitative and quantitative implications of general equilibrium models using computational experiments. Finally, I show how random algorithms can be used for generalizing examples in high‐dimensional problems.