The risks connected with accidents on highways and railways

Quality & Quantity - Safety in an integral sense is a comprehensive tool by which the humans ensure the level of their security and the sustainable development of them and of other basic public...     

A Monte Carlo permutation test for co-occurrence data

Researchers commonly use co-occurrence counts to assess the similarity of objects. This paper illustrates how traditional association measures can lead to misguided significance tests of co-occurrence in settings where the usual multinomial sampling assumptions do not hold. I propose a Monte Carlo permutation test that preserves the original distributions of the co-occurrence data. I illustrate the test on a dataset of organizational categorization, in which I investigate the relations between organizational categories (such as “Argentine restaurants” and “Steakhouses”).     

The role of environmental factors in water utilities’ technical efficiency. Empirical evidence from Spanish companies

This article computes input-specific scores of technical efficiency for a sample of water utilities located in the southern Spanish region of Andalusia. In addition, differences in efficiency between different operating environments are investigated. Concerning the debate about ownership and efficiency, we find that privately owned companies outperform public utilities in their management of labour. Furthermore, technical efficiency is found to be greater among firms located in highly populated areas and for utilities providing water services to tourist municipalities. Finally, no empirical evidence supporting the greater technical efficiency of consortia of water utilities, a managerial strategy strongly encouraged by regional politicians, is found.     

Quantile serial dependence in crude oil markets: evidence from improved quantilogram analysis with quantile wild bootstrapping

We examine the quantile serial dependence in crude oil prices based on the Linton and Whang’s quantile-based portmanteau test which we improved by means of quantile wild bootstrapping (QWB). Through Monte Carlo simulation, we find that the quantile wild bootstrap-based portmanteau test performs better than the bound testing procedure suggested by Linton and Whang. We apply the improved test to examine the efficiency of two crude oil markets – WTI and Brent. We also examine if the dependence is stable via rolling sample tests. Our results show that both WTI and Brent are serially dependent in all, except the median quantiles. These findings suggest that it may be misleading to examine the efficiency of crude oil markets in terms of mean (or median) returns only. These crude oil markets are relatively more serially dependent in non-median ranges.     

The influence of the regional context on firms’ innovation patterns: evidence from Ecuador*

ABSTRACT

Using data from the Ecuadorean Innovation Survey of 2015, this paper identifies the innovation patterns that can be found in Ecuador. In addition, we analyse the influence of the regional innovation systems in determining these patterns. The results show that there are six differentiated patterns of innovation, although they all are related to the adoption and imitation of technologies. Finally, we observe that different regional characteristics condition the way in which firms organise innovation.     

Promotion tournaments in market equilibrium

This paper studies how promotion tournaments motivate workers to accumulate human capital when wages are constrained by outside labor markets. Patient firms can retain some control over tournament prizes through a relational contract, but if the firms are competitive, full efficiency does not obtain in equilibrium even for discount factors arbitrarily close to one. Full efficiency, however, may be feasible in firms with superior technologies; thus, technological efficiency breeds incentive efficiency. The paper also shows that a wage floor leads to insufficient human capital investment in competitive firms, but could lead to excessive investment in technologically superior firms.