Human–capital investment and the wage gap

Summary. According to empirical studies, the wage differential by skills evolved non–monotonically in the past decades although the relative supply of skilled labor steadily increased. The present paper provides a theoretical explanation for this finding. In our setting, technological change intertemporally alters the human–capital investment incentives of heterogeneous individuals. As a consequence of changing incentives, the time path of the relative wage is U–shaped while there is a rise in the share of skilled workers. Received: November 28, 2000; revised version: January 30, 2001     

Pricing, learning, and strategic behavior in a single-sale model

Summary. We analyze an infinite horizon model where a seller who owns an indivisible unit of a good for sale has incomplete information about the state of the world that determines not only the demand she faces but also her own valuation for the good. Over time, she randomly meets potential buyers who may have incentives to manipulate her learning process strategically. We show that i) the seller's incentives to post a high price and to experiment are not necessarily monotonic in the information conveyed by a buyer's rejection; and ii) as the discount factors tend to one, there are equilibria where the seller always ends up selling the good at an ex-post individually rational price. Received: January 6, 1999; revised version: July 15, 2000     

国有企业民营化的均衡模型

本文是来自于中国近年来实行民营化改制实践的一个理论结晶。该研究在中国特定的渐进改革基础上 ,讨论了民营化发生的原因和阻力 ,以及国有企业的利益相关者在改制过程中的利益权衡行为 ,并根据它们的相互关系和目标行为建立了民营化的均衡模型。模型的核心是企业家的最优目标函数 ,这是关系到企业能否实现成功改制的关键。模型的约束条件反映了利益相关者的基本利益保障 ,不会由于改制而受到损害。因此 ,均衡条件的满足表明了最优化改制的实现。通过对模型的分析发现 ,能够满足民营化最优均衡的退出条件 ,就是国有企业退出的最佳时机选择。企业净资本价值、企业家对股权的收购值与职工补偿值之间的合理比例的区间 ,是形成民营化均衡模型的最优解的取值范围。模型的政策含义在于纠偏作用 ,尤其是政府实际的退出时机与改制均衡的最佳退出时机的不一致 ,对于职工利益的损害或缺乏企业家最优目标行为的改制 ,都是脱离了最优轨道的结果 ,需要进行纠正     

The effect of fertility on labour force participation: The Spanish evidence

Abstract. The aim of this paper is to estimate the effect of fertility on the decision of labour force participation of married females in Spain, allowing for the existence of unobserved characteristics that affect both fertility and participation. We use a pooling of five waves of the European Household Panel for Spain (1994–1998). Results indicate that not taking into account the unobserved characteristics that affect both variables imposes on average a strong downward bias on the true effect of fertility on participation. This bias is especially strong for highly educated females. We are grateful to Raquel Carrasco and an anonymous referee for helpful comments. Financial support from Gobierno Vasco (PI-1999-160)), Ministry of Education and Science (BE2000-1394), Instituto de la Mujer and Universidad del País Vasco (UPV 00035.321-13511/2001) is gratefully acknowledged.     

Is capital a collusion device?

Summary. We examine how irreversible capital reduces the possibility of a duopoly to sustain implicit collusion by grim strategies, when the product is homogenous and firms compete in quantities. Compared with the case of reversible capital, there are two countervailing effects: Deviation from an existing collusion is less attractive, because capital once installed causes costs forever. But the punishment will also be less severe due to the high capacity the deviating firm can build before punishment starts. The last effect dominates, meaning that the commitment value of capital is negative for all firms. If capital is irreversible, collusion breaks down for realistic magnitudes of interest rates. Received: April 30, 1999; revised version: November 30, 2001     

The equilibrium set of two-player games with complementarities is a sublattice

Summary. I prove that the equilibrium set in a two-player game with complementarities, and totally ordered strategy spaces, is a sublattice of the joint strategy space. Received: May 31, 2001; revised version: October 4, 2002     

The proper panel econometric specification of the gravity equation: A three-way model with bilateral interaction effects

We argue that the proper specification of a panel gravity model should include main (exporter, importer, and time) as well as time invariant exporter-by-importer (bilateral) interaction effects. In a panel of 11 APEC countries, the latter are highly significant and account for the largest part of variation. First version received: February 2001/Final version received: June 2002 RID="*" ID="*"  We are grateful to two anonymous referees and Robert Kunst for their helpful comments.     

Double Moral Hazard,Monitoring, and the Nature of Contracts

generalized double-sided moral-hazard model, with risk-averse parties who mutually monitor each other (to get a reasonable idea of outcome/effort). The model considers trade-off between monitoring costs and moral hazard costs, which are endogenously determined by the extent of monitoring. Using this model, we formally prove a generalized version of Coase's conjecture – that the optimal contract minimizes the agency and risk costs. We then show how varying assumptions about the feasibility or cost of monitoring of the outcome or the worker's effort lead to different contracts being optimal. The analysis is then used to explain the nature of contracts observed in practice under many different situations. We will give an explanation as to why industrial workers typically work under wage contracts, while share contracts are common in agriculture and will explain why profit sharing is more common for senior managers than for the production workers. Received September 19, 2000; revised version received October 30, 1997     

The impact of product diversification strategy on the corporate performance of large Spanish firms

We analyze the impact of product diversification on performance. This topic has been discussed in the literature, and there is no consensus so far as to the significance or the direction of the impact. Performance is measured using Tobin's q for a sample of 103 large, non-financial Spanish firms (1992–1995). Diversification is measured by means of a categorical variable, as suggested by Varadarajan. The principal results indicate that the firms with intermediate levels of product diversification have the highest performance, while the firms with low and high levels of diversification show significantly lower performance, which performance is not significantly different between them.