Optimality conditions¶and bubbles in sequential economies¶and bounded relative risk-aversion

We provide specific qualifications in order that Kuhn–Tucker type Euler equations and transversality conditions at infinity hold in stochastic equilibrium models with heterogeneous agents and where assets are traded in sequential markets. It is not assumed that uncertainty is modeled as an event-tree structure or that preferences are necessarily bounded. We also describe an important class of preferences based on bounded relative risk aversion which yields relevant simplifications. Our results are used to establish conditions that rule out asset pricing bubbles. Specific examples of economies with bubbles are also discussed. Received: 28 January 2002 / Accepted: 19 July 2002 We are grateful to the editor and an anonymous referee for their valuable comments. This research was partially supported by MURST (Italy), National Group on “Nonlinear Dynamics and Stochastic Models in Economics and Finance”.     

Exploring efficient sets and equilibria on risky assets with APABO DSS prototype version 2.1

ABAPO 2.1 (Assets/Business(es) Analyser and Portfolio Optimizer) is a DSS prototype for portfolio managers. It assists the decision maker in two important stages of his task. First, it provides an integrated synthesis of the returns scenario in order to support the decision maker in the selection of the assets to retain, in accordance with his strategy. Second, on the retained assets it computes and shows the E- efficient solutions. For each efficient portfolio ABAPO supplies immediately a lot of information that should help the decision maker to single out the portfolio which fits his goals best.ABAPO works on an integration of elements derived from the Portfolio Selection Theory, the Capital Asset Pricing Model, the Utility Theory. ABAPO uses the principal component, the univariate, the bivariate regression and the correlation analysis, a parametric quadratic programming model and an algorithm based on the critical line method.ABAPO is implemented in C language under AIX operating system and runs on a IBM RT PC 6150. It is a ductile, interactive procedure that involves graphics in order to increase the efficiency and the effectiveness of the what if simulations.This version 2.1 improves upon the previous one by the evaluation of the Security Market Line, some statistics on the returns of the efficient portfolios, the evaluation of the quadratic indifference curves associated to the efficient portfolios.Research supported by the Italian National Research Council (CNR), grant n. 88.03065.10. ABAPO DSS 2.1 prototype has been developed with the support of the CNR (grant n. 87.1210.10), of the Banca Popolare di Verona, of the Cassa di Risparmio di Verona Vicenza e Belluno, of the Società Cattolica di Assicurazione, at the Istituto di Matematica, Università di Verona.     

A comparison of different trading protocols in an agent-based market

We compare price dynamics of different market protocols (batch auction, continuous double auction and dealership) in an agent-based artificial exchange. In order to distinguish the effects of market architectures alone, we use a controlled environment where allocative and informational issues are neglected and agents do not optimize or learn. Hence, we rule out the possibility that the behavior of traders drives the price dynamics. Aiming to compare price stability and execution quality in broad sense, we analyze standard deviation, excess kurtosis, tail exponent of returns, volume, perceived gain by traders and bid-ask spread. Overall, a dealership market appears to be the best candidate, generating low volume and volatility, virtually no excess kurtosis and high perceived gain.     

Product attributes and models of multiple discreteness

Demand for product characteristics is examined within the context of models that allow for both corner and interior solutions corresponding to zero and non-zero demand. Product attribute information is associated with marginal utility and curvature (satiation) parameters of various utility functions. Empirical applications demonstrate the need for incorporating characteristics in a fairly general way. We also compare our approach to an ideal point and pure Lancasterian versions of our nonlinear utility model. The data support our model over either the ideal point or Lancasterian variants.     

New Evidence from Brazil on Trade Liberalization and Productivity Growth*

This article presents evidence on the positive effect of international trade on productivity growth using industrial level data preceding and following Brazil's trade liberalization in 1988–90. Our data reveal large and widespread productivity improvement across industries after barriers to trade were drastically reduced. Econometric results confirm the association between trade liberalization and productivity growth and show that the impact was indeed substantial: The observed tariff reduction in the period brought a 6% estimated increase in total factor productivity growth rate and a similar impact on labor productivity.     

Police-Monitored Cameras and Crime*

We study the effects of police monitoring on crime. We exploit detailed information on the location and date of installation of police-monitored surveillance cameras, coupled with data at the street-segment level on all reported crimes in the city of Montevideo, Uruguay. We find that the introduction of police-monitored surveillance cameras reduces crime by about 20 percent in monitored areas relative to a pure control group located outside the city. We also explore potential displacement effects, and we do not find evidence of such effects.     

Optimal monetary policy in a New Keynesian model with habits in consumption

In this paper we consider the implications of habits for optimal monetary policy, when those habits either exist at the level of the aggregate basket of consumption goods (‘superficial’ habits) or at the level of individual goods (‘deep’ habits: see Ravn et al., 2006). External habits generate an additional distortion in the economy and create new trade-offs for optimal policy, as the policy maker does not respond as aggressively to technology shocks in order to avoid exacerbating the habits externality. This can dramatically affect both the parameterization of optimal simple rules, as well as their determinacy properties. These effects are particularly strong when habits are of the deep kind.     

The usefulness of performance reporting in local government: comparing Italy and Spain

This article presents a comparative analysis of the perceived usefulness of performance information by managers in local authorities in Italy and Spain. Italy and Spain have similar cultural and administrative characteristics and in both countries there are external requirements (from central government) to adopt performance indicators. The adoption of performance indicators was found to be almost symbolic in both states.     

ERROR-CORRECTION, ⇐ SURPRISE ⇒ MODELS AND THE DIFFERENTIAL APPROACH TO THE CONSUMPTION FUNCTION(*)

The paper provides a general theoretical framework that allows a comparison and a possible reconciliation of error correction models of consumers’behaviour and the life cycle hypothesis under rational expectations. It is suggested that by relaxing the assumption of intertemporally strongly separable and homothetic preferences, a generalization of Hall's random walk model can be derived, containing an error correction mechanism.     

Reference group influence on binary choices dynamics

The recent literature has analyzed binary choices dynamics providing interesting results. Most of these contributions consider interactions within a single group. Nevertheless, in some situations the interaction takes place not only within a single group but also between different groups. In this paper, we investigate the choice dynamics when considering two populations where one serves as a reference group. Considering this influence effect enriches the dynamics. Although the structurally stable resulting dynamics are attracting cycles only, with any positive integer period, the reference group makes the dynamics of the influenced population much more complex. We considered both the possibility that the reference group has the same or the opposite attitude toward the distribution over the choices. We show how the dynamics and the bifurcation structure are modified under the influence of the reference group. Our results illustrate how the propensity to switch choices in the reference groups may, indirectly, affect choices in the first group.