Designing the European Road Safety Observatory

The unavailability of consistent traffic accident data and road safety information limits the opportunities to provide target approaches to reduce road crashes. The European commission has decided to meet the demand for this data by establishing a new Road Safety Observatory. The structure and much of the initial content is being developed within the SafetyNet Integrated Project. This paper describes the structure of its key components.     

MARKET ECONOMIES WITH AN ENDOGENOUS SOCIAL DIVISION OF LABOR

I consider a general equilibrium model of a competitive market economy in which production is conducted through an endogenous social division of labor. I represent economic decision makers as “consumer–producers,” who consume as well as produce commodities. In this approach, the emergence of a nontrivial social division of labor is guided by Increasing Returns to Specialization (IRSpec) in production. Under IRSpec, I show existence of competitive equilibria, the two fundamental theorems of welfare economics, and characterize these equilibria. Markets equilibrate through the adjustment of the social division of labor; the production technologies completely determine the equilibrium prices.     

Interpretable Machine Learning Using Partial Linear Models*

Despite their high predictive performance, random forest and gradient boosting are often considered as black boxes which has raised concerns from practitioners and regulators. As an alternative, we suggest using partial linear models that are inherently interpretable. Specifically, we propose to combine parametric and non-parametric functions to accurately capture linearities and non-linearities prevailing between dependent and explanatory variables, and a variable selection procedure to control for overfitting issues. Estimation relies on a two-step procedure building upon the double residual method. We illustrate the predictive performance and interpretability of our approach on a regression problem.     

Diversification and portfolio theory: a review

Financial Markets and Portfolio Management - Diversification is one of the major components of investment decision-making under risk or uncertainty. However, paradoxically, as the 2007–2009...     

Fast and realistic European ARCH option pricing and hedging

The behavior of the implied volatility surface for European options was analysed in detail by Zumbach and Fernandez for prices computed with a new option pricing scheme based on the construction of the risk-neutral measure for realistic processes with a finite time increment. The resulting dynamics of the surface is static in the moneyness direction, and given by a volatility forecast in the time-to-maturity direction. This difference is the basis of a cross-product approximation of the surface. The subsequent speed-up for option pricing is large, allowing the computation of Greeks and the delta replication strategy in simulations with the cost of replication and the replication risk. The corresponding premia are added to the option arbitrage price in order to compute realistic implied volatility surfaces. Finally, the cross-product approximation for realistic prices can be used to analyse European options on the SP500 in depth. The cross-product approximation is used to compute a mean quotient implied volatility, which can be compared with the full theoretical computation. The comparison shows that the cost of hedging and the replication risk premium have contributions to the implied volatility smile that are of similar magnitude to the contribution from the process for the underlying asset.     

Empirical properties of large covariance matrices

The salient properties of large empirical covariance and correlation matrices are studied for three datasets of size 54, 55 and 330. The covariance is defined as a simple cross product of the returns, with weights that decay logarithmically slowly. The key general properties of the covariance matrices are the following. The spectrum of the covariance is very static, except for the top three to 10 eigenvalues, and decay exponentially fast toward zero. The mean spectrum and spectral density show no particular feature that would separate ‘meaningful’ from ‘noisy’ eigenvalues. The spectrum of the correlation is more static, with three to five eigenvalues that have distinct dynamics. The mean projector of rank k on the leading subspace shows that a large part of the dynamics occurs in the eigenvectors. Together, this implies that the reduction of the covariance to a few leading static eigenmodes misses most of the dynamics. Finally, all the analysed properties of the dynamics of the covariance and correlation are similar. This indicates that a covariance estimator correctly evaluates both volatilities and correlations, and separate estimators are not required.     

West African Single Currency and Competitiveness

This paper compares different nominal anchors to promote internal and external competitiveness in the case of a fixed exchange rate regime for the future single regional currency of the Economic Community of the West African States (ECOWAS). We use counterfactual analyses and estimate a model of dependent economy for small commodity exporting countries. We consider four foreign anchor currencies: the US dollar, the euro, the yen and the yuan. Our simulations show little support for a dominant peg in the ECOWAS area if they pursue several goals: maximizing the export revenues, minimizing their variability, stabilizing them and minimizing the real exchange rate misalignments from the fundamental value.     

Optimal unemployment insurance: transitional dynamics vs. steady state

In this study, we ask whether the presence of precautionary savings substantially reduces the optimal replacement rate in an European economy type characterized by high unemployment benefits and moral hazard. We build a simple job search model calibrated on French data and, in line with previous studies, find that the optimality criterion based on comparisons of steady states leads to a low optimal ratio. Yet, this result ignores potential transitional costs due to the necessity for agents to increase their savings and reduce their consumption whenever the ratio is cut. We therefore build a dynamic model taking full account of the transition, and show that a reduction in benefits reduces welfare. Even though the long-run optimal replacement rate is lower than the current one, transitional costs dominate long-run gains.     

Are individuals with entrepreneurial characteristics more likely to engage in destruction? An experimental investigation among potential 21st century entrepreneurs in Tunisia

We test experimentally whether individuals high in some entrepreneurial characteristics are more likely to engage in destructive behavior than other individuals. In the joy-of-destruction game, participants can either preserve or costly burn the endowment of each other. In some treatments they can hide from other participants whether they are responsible for destruction. We found that participants high in some entrepreneurial characteristics are significantly more likely to adopt destructive behaviours.