Economic Growth with Imperfect Protection of Intellectual Property Rights

This paper examines the growth effects of intellectual property right (IPR) protection in a quality-ladder model of endogenous growth. Stronger IPR protection, which reduces the imitation probability, increases the reward for innovation. However, stronger protection also gradually reduces the number of competitive sectors, in which innovation is easier than in monopolistic sectors. With free entry to R&D, the number of researchers in each remaining competitive sector increases, but the concentration of R&D activity raises the possibility of unnecessary duplication of innovation, thereby hindering growth. Consequently, imperfect rather than perfect protection maximizes growth. Welfare and scale effects are also examined.     

Seasonality and Markov switching in an unobserved component time series model

It is generally acknowledged that the growth rate of output, the seasonal pattern, and the business cycle are best estimated simultaneously. To achieve this, we develop an unobserved component time series model for seasonally unadjusted US GDP. Our model incorporates a Markov switching regime to produce periods of expansion and recession, both of which are characterized by different underlying growth rates. Although both growth rates are time-varying, they are assumed to be cointegrated. The analysis is Bayesian, which fully accounts for all sources of uncertainty. Comparison with results from a similar model for seasonally adjusted data indicates that the seasonal adjustment of the data significantly alters several aspects of the full model. First Version Received: January 2001/Final Version Received: February 2002 Send offprint requests to: Rob Luginbuhl?Correspondence to: Rob Luginbuhl     

The Manipulability of Matching Rules via Segmentation

Our matching problems feature agents with endowments facing certain division rules. At any matching, the endowments of agents are reallocated between the matched pairs according to some given division rule, and this opens doors to an iterated matching problem and rematching, and to manipulation of some matching rules via segmentation. In this form of manipulation a coalition breaks off from the rest, matches within itself and rejoins the complementary coalition for a rematching at the new endowment profile. Under certain division rules this may benefit the coalition who breaks off without hurting the complementary coalition. Furthermore, both may benefit by first matching internally and then rejoining for a new match.     

Candidate stability and nonbinary social choice

Summary. The requirement that a voting procedure be immune to the strategic withdrawal of a candidate for election can be formalized in different ways. Dutta, Jackson, and Le Breton (Econometrica, 2001) have recently shown that two formalizations of this candidate stability property are incompatible with some other desirable properties of voting procedures. This article shows that Grether and Plott's nonbinary generalization of Arrow's Theorem can be used to provide simple proofs of two of their impossibility theorems. Received: August 15, 2001; revised version: March 11, 2002 RID="*" ID="*" Parts of this article were previously circulated in somewhat different form in a working paper with the same title by the second author. We are grateful to Michel Le Breton and an anonymous referee for their comments. Correspondence to:J.A. Weymark     

Sample attrition and labor force dynamics: Evidence from the Spanish labor force survey

In this paper we examine a number of issues that arise in investigating labor force dynamics using the Spanish Labor Force Survey (EPA). These issues are by no means specific to the Spanish case and apply to most European-style labor force surveys. Our main conclusions may be summarized as follows. First, survey nonresponse cannot be neglected. Second, the EPA tends to underestimate employment and participation of high-educated young people, and to overestimate those of the low-educated elderly. Finally, we find little evidence that attrition causes important selection biases in estimating quarterly transition probabilities.     

Intraday Empirical Analysis and Modeling of Diversified World Stock Indices

This paper proposes an approach to the intraday analysis of diversified world stock accumulation indices. The growth optimal portfolio (GOP) is used as reference unit or benchmark in a continuous financial market model. Diversified portfolios, covering the world stock market, are constructed and shown to approximate the GOP, providing the basis for a range of financial applications. The normalized GOP is modeled as a time transformed square root process of dimension four. Its dynamics are empirically verified for several world stock indices. Furthermore, the evolution of the transformed time is modeled as the integral over a rapidly evolving mean-reverting market activity process with deterministic volatility. The empirical findings suggest a rather simple and robust model for a world stock index that reflects the historical evolution, by using only a few readily observable parameters. Mathematics Subject Classification: (1991) primary 90A12, secondary 60G30,62P20 JEL Classification: G10, G13     

Strategic Price Discrimination in Compulsory Insurance Markets

This paper considers price discrimination when competing firms do not observe a customer’s type but only some other variable correlated to it. This is a typical situation in many insurance markets—such as motor insurance—where it is also often the case that insurance is compulsory. We characterise the equilibria and their welfare properties under various price regimes. We show that discrimination based on immutable characteristics such as gender is a dominant strategy, either when firms offer policies at a fixed price or when they charge according to some consumption variable that is correlated to costs. In the latter case, gender discrimination can be an outcome of strategic interaction alone in situations where it would not be adopted by a monopolist. Strategic price discrimination may also increase cross subsidies between types, contrary to expectations.JEL Classification No.: L13, G22     

Erklärungsansätze für vertragswidriges Verhalten Versicherungsnehmern aus Sicht der ökonomischen Theorie

The two main purposes of this paper are an introduction to the economic analysis of insurance fraud and furthermore a derivation of factors that determine fraudulent behavior of policyholders on insurance markets. Consequently, we analyze the strategic decision problems of insurance companies and the policyholders and identify some factors that can help to reduce fraudulent behavior. In this context we evaluate two derived starting points for the combat against insurance fraud: fraud detection systems and a consequent charge policy of detected defrauders. We illustrate that both points can help to reduce the cost of fraud. Furthermore, we enhance our earlier analysis with respect to the empirical fact that some individuals care about fairness or — in the insurance fraud context — the legitimacy of their actions. Surprisingly, in some market situations these concerns of some policyholders do not lead to a lower fraud probability. Finally, we discuss how and to what extent insurance companies can influence such ethical concerns of policyholders. On that score, we distinguish insurance specific and insurance unspecific factors and their impact on the consumers attitudes towards insurance fraud.