Accomplice Witnesses and Organized Crime: Theory and Evidence from Italy

We develop an agency model of organized crime accounting for the main trade‐offs involved in the introduction of an accomplice‐witness program. We characterize the optimal policy and identify its main determinants in a framework where public officials can be dishonest. Our predictions are tested by using data for Italy before and after the introduction of the 1991 accomplice‐witness program. As predicted by the model and the earlier antitrust literature, the program appears to have strengthened deterrence and enhanced prosecution. Moreover, consistent with a novel prediction of our theory, the evidence suggests that the program efficacy is affected by the judicial system efficiency.     

Multiple equilibria and global indeterminacy in an endogenous growth model with congestible public goods

This paper extends the findings in Chen and Lee (2007) to show that the use of congestible public goods can produce both local and global indeterminacy in a two‐sector endogenous growth model with productive public services financed by income taxation. Basically, we observe the effects on growth rates by changing parameters, and compare the case of a single steady‐state with the emergence of dual steady‐states, identifying the feasible ways to avoid a possible low‐growth poverty trap. The novelty of our analysis is to detect the presence of global indeterminacy by making use of the Bogdanov‐Takens bifurcation theorem. Some examples are also provided to achieve concrete policy implications.     

An application of dynamic specifications of factor demand equations to interfuel substitution in US industrial energy demand

In a recent paper, Jones (1995) [A dynamic analysis of the interfuel substitution in US industrial energy demand. J. Bus. Econ. Stat. 13 (4), 459–465] presents a dynamic analysis of interfuel substitution in US industry energy demand. The author concludes that a dynamic linear logit model is ‘superior' to a comparable dynamic translog model. The latter in fact violates concavity conditions whilst the logit formulation does not. This paper shows first of all that the dynamic formulation of the translog used in Jones (1995) is mis-specified. In fact, a parsimonious error-correction model (ECM) ‘dominates' alternative dynamic formulations, amongst which the partial adjustment mechanism used by the author. The ECM is able to generate optimal estimates of long-run and short-run elasticities, and it satisfies the concavity conditions of the cost function. Further, the theoretical framework used in this paper is the one recently proposed by Urga (1996) [On the identification problem in testing dynamic specification of factor demand equations. Econ. Lett. 52, 205–210] and Allen and Urga (1998) [Derivation and estimation of interrelated factor demands from dynamic cost function. Forthcoming in Economica]. It allows one to identify all coefficients (long-run and short-run) of the dynamic formulation via the joint estimation of the ‘effective' (short-run) cost function and the set of factor demand equations. This strategy solves, amongst other things, the parameter identification problem within the set of demand equations themselves, an issue which was originally noted by Anderson and Blundell (1982) [Estimation and hypothesis testing in dynamic singular equation systems. Econometrica, 1559–1571], re-addressed by Friesen (1992) [Testing dynamic specification of factor demand equations for US manufacturing. Rev. Econ. Stat. LXXIV (2), 240–250] and, more recently, by Urga (1996) and Allen and Urga (1998).     

A baseline model of industry evolution

The paper analyses some general dynamic properties of industries characterized by heterogeneous firms and continuing stochastic entry.After a brief critical assessment of some significant drawbacks of recent contributions to modeling of stochastic industrial dynamics, we propose a novel analytical apparatus able to derive some generic properties of the underlying competition process combining persistent technological heterogeneity, differential growth of individual firms and turnover. The basic model, we suggest, is indeed applicable with proper modifications to a large class of evolutionary processes, well beyond industrial dynamics.JEL Classification: L11, O30, C60Support to this research by the International Institute for Applied Systems Analysis (IIASA), Austria; the Fujitsu Research Institute for Advanced Information (FRI), Japan; the Italian National Research Council (CNR), the Italian Ministry of Education, University and Research (MIUR, prot. 2002132413 003) and the Free University of Bozen Bolzano, Italy, is gratefully acknowledged. Comments by Andrea Bassanini, Francesca Chiaromonte, Steven Klepper, Uwe Cantner, Drew Fudenberg and the anonymous referees helped in shaping the paper to its present form. Mariele Berté provided the computer simulations of the model. The usual caveats apply.Correspondence to: G. Dosi     

Killing off cohorts: Forecasting mortality of non-extinct cohorts with the penalized composite link model

Mortality forecasting has crucial implications for insurance and pension policies. A large amount of literature has proposed models to forecast mortality using cross-sectional (period) data instead of longitudinal (cohort) data. As a consequence, decisions are generally based on period life tables and summary measures such as period life expectancy, which reflect hypothetical mortality rather than the mortality actually experienced by a cohort. This study introduces a novel method to forecast cohort mortality and the cohort life expectancy of non-extinct cohorts. The intent is to complete the mortality profile of cohorts born up to 1960. The proposed method is based on the penalized composite link model for ungrouping data. The performance of the method is investigated using cohort mortality data retrieved from the Human Mortality Database for England & Wales, Sweden, and Switzerland for male and female populations.     

Numerical evaluation of the critical price and American options

An approximate solution to the American put value is proposed and implemented numerically. Relaxation techniques enable the critical price to be determined with high accuracy. The method uses a modification of the quadratic approximation of MacMillan and Barone-Adesi and Whaley which gives an expression for the critical price. Numerical experimentation and iterative methods quickly provide highly accurate solutions.     

How limiting deceptive practices harms consumers

There are two competing sellers of an experience good, one offers high quality, one low. The low‐quality seller can engage in deceptive advertising, potentially fooling a buyer into thinking the product is better than it is. Although deceptive advertising might seem to harm the buyer, we show that he could be better off when the low‐quality seller can engage in deceptive advertising than not. We characterize the optimal deterrence rule that a regulatory agency seeking to punish deceptive practices should adopt. We show that greater protection against deceptive practices does not necessarily improve the buyer welfare.     

An integrated multi-model credit rating system for private firms

This paper presents a integrated credit risk modelling approach for private firms which fulfil 2001 Basel Accord requirements in the case of the adoption of the foundation approach. Our model comprises: (a) a bottom-up technique to initially assess the through-the-cycle one-year Probability of Default (PD) and (b) a top-down approach to refine and calibrate this historical PD in a forward-looking credit risk assessment based on next year’s economic outlook. We present findings from applying this model to a large sample of client firms of the Bank of Rome.     

Explaining UK wage inequality in the past globalisation period, 1880–1913

The current era of globalisation has witnessed a rising premium paid to skilled workers resulting in increasing wage inequality in most OECD countries. This pattern differs from that observed during the past globalisation period (1880–1913), in which wage inequality decreased in most of the Old World countries. The present debate over wage inequality focuses on the implications of globalisation, technological change, the role of labour market institutions and education. Similar factors were at work in the past globalisation process. In order to disentangle the main factors that contribute to wage inequality, we calibrate a general equilibrium model for the UK economy in the past globalisation period. The results show that a trade shock and a skilled-biased technology shock increased wage inequality. However, education and emigration had a more significant impact and led to a decrease in wage inequality.     

Bounds for Functions of Dependent Risks

The problem of finding the best-possible lower bound on the distribution of a non-decreasing function of n dependent risks is solved when n=2 and a lower bound on the copula of the portfolio is provided. The problem gets much more complicated in arbitrary dimensions. When no information on the structure of dependence of the random vector is available, we provide a bound on the distribution function of the sum of risks which we prove to be better than the one generally used in the literature.