Codes of Conduct in Subcontracting Networks: A Labour Law Perspective

In the past ten years, many European companies organised into subcontracting networks have decided to adopt codes of conduct to regulate labour relations and to ensure the respect of fundamental social rights. This paper first determines the context and the issues to be addressed by codes of conduct within networks of companies, and second analyses the terms under which they can be implemented. The paper argues that codes of conduct can complement the standards developed by States, the European Union or the social partners, but that steps should be taken in order to avoid that these texts replace the existing labour law.     

Stochastic Models of Implied Volatility Surfaces

We propose a market–based approach to the modelling of implied volatility, in which the implied volatility surface is directly used as the state variable to describe the joint evolution of market prices of options and their underlying asset. We model the evolution of an implied volatility surface by representing it as a randomly fluctuating surface driven by a finite number of orthogonal random factors. Our approach is based on a Karhunen–Loeve decomposition of the daily variations of implied volatilities obtained from market data on SP500 and DAX options.
We illustrate how this approach extends and improves the accuracy of the well–known 'sticky moneyness' rule used by option traders for updating implied volatilities. Our approach gives a justification for the use of 'Vegas' for measuring volatility risk and provides a decomposition of volatility risk as a sum of independent contributions from empirically identifiable factors.
(J.E.L.: G130, C14, C31).     

Changing rewards in contests: Has the three-point rule brought more offense to soccer?

In the mid-nineties FIFA decided to increase from two to three the number of points assigned to the winning team of a soccer match played under traditional round-robin national leagues. Since a game of soccer can be regarded as a contest, FIFA's measure provides an interesting case-study for analysing how a change in the system of rewards (from a zero to a non-zero sum rule) may affect the contestants' equilibrium behaviour. In this paper we try to assess, both theoretically and empirically, whether FIFA's new point rule has changed soccer towards a more offensive game, in which teams adopt more risky strategies. In particular, we evaluate the “na?ve hypothesis” according to which the measure would induce every team to play always more offensively, and we explore the extent to which the change in teams' behaviour may be affected by quality differentials between teams. Our most important hypothesis is that when the asymmetry between opposing teams is large enough, an increase in the reward for victory induces the weaker team to play more defensively, rather than the opposite. By looking at a subset of matches held in the Portuguese first division league, which approximate the conditions of our model, we find support for this hypothesis. First version received: July 1999/Final version received: May 2001     

An Eclectic Approach to Estimating U.S. Potential GDP

Rennison (Comparing alternative output gap estimations: a Monte Carlo approach, 2003) has provided simulation-based evidence showing that the joint use of extended multivariate filters and structural vector autoregression models is optimal for estimating potential output. We use this approach to estimate the two components of potential GDP: the full-employment labour input and trend labour productivity. This decomposition is useful for identifying sources of fluctuations in potential output. It reveals, for example, that the vigorous growth rate of U.S. potential GDP recorded during the second half of the 1990s is attributable to a fall in the structural rate of unemployment and a marked upswing in trend productivity growth.     

On the impact of leverage constraints on asset prices and trading volume

Abstract. Researchers have used stylized facts on asset prices and trading volume in stock markets (in particular, the mean reversion of asset returns and the correlations between trading volume, price changes and price levels) to support theories where agents are not rational expected utility maximizers. This paper shows that this empirical evidence is in fact consistent with a standard infinite horizon – perfect information – expected utility economy where some agents face leverage constraints similar to those found in todays financial markets. In addition, and in sharp contrast to the theories above, we explain some qualitative differences that are observed in the price-volume relation on stock and on futures markets. We consider a continuous-time economy where agents maximize the integral of their discounted utility from consumption under both budget and leverage constraints. Building on the work by Vila and Zariphopoulou (1997), we find a closed form solution, up to a negative constant, for the equilibrium prices and demands in the region of the state space where the constraint is non-binding. We show that, at the equilibrium, stock holdings volatility as well as its ratio to stock price volatility are increasing functions of the stock price and interpret this finding in terms of the price-volume relation. We would like to thank the editor and two anonimous referees for valuable substantive comments. Our gratitude also to Franklin Allen, Kerry Back, Domenico Cuoco, Xavier Freixas, Sanford Grossman, Michel Habib, Lutz Hendricks, Richard Kihlstrom, Fernando Restoy, Mary Thomson, Jean-Luc Vila, participants to seminars at Birkbeck College, Carnegie-Mellon, Columbia, ESSEC, HEC, IAE, INSEAD, London Business School, London School of Economics, McGill, Michigan, National University of Singapore, Pompeu Fabra, North Carolina, Washington-St-Louis, Wharton, the Jornadas de Economía Financiera BBV, and the Meetings of the Society for Economic Dynamics and Control and the American Finance Association. Special thanks are due to Süleyman Basak for his enthusiastic support and many helpful suggestions. The usual disclaimer applies. We gratefully acknowledge the support of the BBV and Caja de Madrid Foundations and CREF (both authors) and of the Spanish Ministry of Education under DGICYT grant no. PB93-0388 (first author).     

Top dominance and the possibility of strategy-proof stable solutions to matching problems

Summary This paper explores the possibility of designing strategy-proof mechanisms yielding satisfactory solutions to the marriage and to the college admissions problem. Our first result is negative. We prove that no strategy-proof mechanism can always choose marriages that are individually rational and Pareto efficient. This strengthens a result by Roth (1982) showing that strategy-proof mechanisms cannot always select stable marriages. The result also applies, a fortiori, to college admissions. Since finding difficulties with strategy-proofness is quite an expected result, we then address a second question which is classical within the incentives literature. Are there restrictions on the preferences of agents under which strategy-proof and stable mechanisms do exist? We identify a nontrivial restriction on the domain of preferences, to be called top dominance, under which there exist strategy-proof and stable mechanisms for both types of matching problems. The mechanisms turn out to be exactly those that derive from the most classical algorithms in the literature; namely, the women's optimal, the men's optimal and the student's optimal. Finally, top dominance is shown to be essentially necessary, as well as sufficient, for the existence of strategy-proof stable matching mechanisms.This work is partially supported by grant PB 89-0294, from the Directión General de Investigatión Ciencia y Tecnología of the Spanish Ministerio de Educación y Ciencia. Salvador Barberà is also grateful to the Instituto de Estudios Fiscales. This research was initiated while both authors were visting GREMAQ, Université des Sciencies Sociales, Toulouse, whose hospitality is gratefully acknowledged. The paper extends results that were circulated as GREMAQ W.P. 91.22.232. We are grateful to Matthew Jackson and Marilda Sotomayor for their comments.     

Choosing sides in the trilemma: international financial cycles and structural change in developing economies

ABSTRACT

This paper analyzes the impact of international financial cycles on structural change in developing economies. It is argued that the impact of these cycles depends on the specific combination of macroeconomic and industrial policies adopted by the developing economy. The cases of Brazil and Argentina are contrasted with those of Korea and China. In the Asian economies, macroeconomic policy has been a complementary tool along with industrial policy to foster the diversification of production and capabilities. Inversely, in the case of the Latin American countries, long periods of real exchange rate (RER) appreciation, combined with the weaknesses (or absence) of industrial policies, contributed to the loss of capabilities and lagging behind.     

Business Ethics in The Philippines

The plurality of languages and ethnicities, the geographic fragmentation, the predominant Roman Catholic religion, together with the still relatively short experience in nationhood account for a very peculiar understanding of "business ethics" in the Philippines. The rapid growth and liberalization of the economy, coupled with the inequitable distribution of wealth, the destruction of the environment and corruption are the main ethical concerns. Businesspersons and the academe endeavor to find creative solutions for these unique challenges.     

Task‐based structures in open source software: revisiting the onion model

Studies on Open Source Software (OSS) developer communities have long stated that there is a relationship between community structure and tasks carried out by project members. This relationship has been exemplified by the onion model, which has been instrumental in understanding self‐coordination in OSS projects. Despite its ubiquity, there is a lack of empirical evidence to validate the relative position of each task cluster within the onion model. In this study, we map out the community structure of a large open source project and observe its bug‐fixing patterns to explore the relationship between tasks and structure. Our study makes three significant contributions. First, we find no empirical evidence to support the structural location of bug‐fixing tasks in the onion structure. Second, we find empirical evidence to support the core‐periphery continuum model linking an actor’s coreness to problem‐solving ability. Third, our results suggest that the importance and location of each task within the core‐periphery structure evolve over time. These findings add clarity to the community structure and their implications for the management and coordination of collaborative innovation projects.