Risk-type density diagrams by crash type on two-lane rural roads

The research presented here aims to plot density diagrams per road crash risk type to identify all possible scenarios where driving is less than safe. The starting point was the prediction of injury crash rate on horizontal homogeneous segments of two-lane rural roads for three main injurious crash types (head-on/side collisions, rear-end crashes, and single-vehicle run-off-road crashes) as observed on the network. A careful analysis of the database shows that a wide variety of factors appear to be influenced or associated with the crash dynamic, as follows: the road scenario (combination of infrastructure and environmental conditions found at the site at the time of the crash), mean lane width, the horizontal curvature indicator (measurement of the curvature change rate), and mean speed. Crashes recorded from 2003 to 2010, of which 1597 were injurious, and 645 resulted only in damage to property, were analyzed on more than 3700?km of road network in Southern Italy. Generalized estimating equations with a negative binomial distribution were implemented. Risk-type density charts were plotted to thoroughly identify all possible combinations of existing explicative variables producing hazardous conditions on the road. The different shades in the diagrams represent different ranges of injurious crash rates: the white band shows low levels, while a black band shows high values. It is not possible to consider working on an explanatory variable to reduce hazardous conditions on the road network without also considering how this variation might affect the influence of the remaining explanatory variables on crash phenomena and, consequently, on the predictive model. The risk maps make it possible to keep under control in a simple and immediate approach the way each variable as a result of variations of a part or of all.     

Stochastic monotonicity in intergenerational mobility tables

The aim of this paper is to test for stochastic monotonicity in intergenerational socio‐economic mobility tables. In other words, we question whether having a parent from a high socio‐economic status is never worse than having one with a lower status. Using existing inferential procedures for testing unconditional stochastic monotonicity, we first test a set of 149 intergenerational mobility tables in 35 different countries and find that monotonicity cannot be rejected in hardly any table. In addition, we propose new testing procedures for testing conditional stochastic monotonicity and investigate whether monotonicity still holds after conditioning on a number of covariates such as education, cognitive and non‐cognitive skills. Based on the NCDS cohort data from the UK, our results provide evidence that monotonicity holds, even conditionally. Moreover, we do not find large differences in our results when comparing social class and wage class mobility. Copyright © 2010 John Wiley & Sons, Ltd.     

Women on the Board and Managers’ Pay: Evidence from Spain

The current literature shows great interest in the issue of gender diversity on boards of directors. Some studies have hypothesized a direct relationship between diversity and the value of the firm, but not many examine the intermediate mechanisms that may exert an influence on such relationships. We employ two stages of GMM estimation methodology to exhibit evidences of the relationship between gender diversity and compensation of top managers in the Spanish context. Results show that gender diversity positively affects the effectiveness of boards—in terms of composition, structure, size and functioning—influencing a proper design of top managers compensation linked to company performance. Evidences suggest that legislative actions aimed at increasing the presence of women on boards of directors are justified not only for ethical reasons, but also for reasons of economic efficiency.     

The contribution of genetics to milk composition: evidence from Spain

This article focuses on the role that genetic progress may play in improving milk quality. Despite important genetic advances in dairy production, the absence of genetic records in farm management databases has precluded empirical production models from explicitly accounting for differences in genetics across herds. The influence of genetics on milk composition is analyzed by splitting milk production into protein, fat, and other components. The article explores some modeling issues associated with the specification of the effect of genetics in this multi‐output technology framework. In particular, genetic indexes are considered as allocable inputs and the remaining inputs as nonallocable. Our results show that genetics have a significant impact on milk composition. In particular, we find that farmers’ income increases by 6.6% when genetic indexes are augmented by one sample standard deviation.     

Multilateral bargaining and Walrasian equilibrium

A class of bargaining games in which agents bargain over prices and maximum trading constraints is considered: It is proved that all the Stationary Subgame Perfect Equilibria of these games implement Walrasian allocations as the bargaining frictions vanish. The result holds for any number of agents and is robust to different specifications of the bargaining process.     

Relevance and advantages of using the item response theory

The item response theory (IRT) also known as latent trait theory, is used for the development, evaluation and administration of standardized measurements; it is widely used in the areas of psychology and education. This theory was developed and expanded for over 50 years and has contributed to the development of measurement scales of latent traits. This paper presents the basic and fundamental concepts of this IRT and a practical example of the construction of scales is proposed to illustrate the feasibility, advantages and validity of IRT through a known measurement, the height. The results obtained with the practical application of IRT confirm its effectiveness in the evaluation of latent traits.     

The Effect of EMU on Tourism*

This paper estimates the effect of the euro on intra‐EMU tourist flows by using a panel dataset of 20 OECD countries over the period 1995–2002. The results reveal that the euro has increased tourism, with an effect of around 6.5%. This is a noticeable impact given the early stage of the EMU analyzed. The robustness checks show that the evidence of a positive impact is quite widespread across EMU destination countries.