Trading horizons and the value of money

This paper shows that fiat money can be feasible and essential even if the trading horizon is finite and deterministic. The result hinges on two features of our model. First, individual actions can affect the future availability of productive resources. So, agents may be willing to sell for money, even if on that date they have no reason to accept it. This makes monetary trade feasible in all preceding dates. Second, agents are anonymous and direct their search for partners. So, gift-giving arrangements may be prevented because agents can misrepresent their consumption needs. This makes money essential in exploiting any gains from specialization and trade.     

A Constitutional Interpretation of the GATT/WTO

Constitutional analysis is used to evaluate the role of the WTO. The following questions are addressed: - can the WTO define and implement its own decisions, rather than those of its members? - if so, does this make it an ‘organised player’, capable of having its own role? - what allows it to exist as an ‘organised player’? My main conclusion is that the WTO's legitimisation depends not only on its safeguarding of existing rules, but also on its long-term ability to maintain equity in the distribution of benefits and costs among member Countries.     

Matching and anonymity

This work introduces a set-theoretic foundation of deterministic bilateral matching processes and studies their properties. In particular, it formalizes a link between matching and informational constraints by developing a notion of anonymity that is based on the agents’ matching histories. It also explains why and how various matching processes generate different degrees of “informational isolation” in the economy. We illustrate the usefulness of our approach to modeling matching frameworks by discussing the classical turnpike model of Townsend.This research is supported in part by the NSF grants EIA-0075506, SES-0128039, DMS-0437210, and ACI-0325846. We thank two anonymous referees for constructive comments that improved the exposition of the paper. We also thank the participants in seminars at the University of Aarhus, Purdue University, University of Texas at Austin, and at the XI Meeting on Real Analysis and Measure Theory in 2004, the spring 2004 Midwest Economic Theory Meeting, the summer 2004 North American and European Econometric Society meetings.     

Alternative approaches for the reformulation of economics

Journal of Economic Interaction and Coordination -     

Alternative Approaches to Multilevel Modelling of Survey Non‐Contact and Refusal

We review three alternative approaches to modelling survey non‐contact and refusal: multinomial, sequential, and sample selection (bivariate probit) models. We then propose a multilevel extension of the sample selection model to allow for both interviewer effects and dependency between non‐contact and refusal rates at the household and interviewer level. All methods are applied and compared in an analysis of household non‐response in the United Kingdom, using a data set with unusually rich information on both respondents and non‐respondents from six major surveys. After controlling for household characteristics, there is little evidence of residual correlation between the unobserved characteristics affecting non‐contact and refusal propensities at either the household or the interviewer level. We also find that the estimated coefficients of the multinomial and sequential models are surprisingly similar, which further investigation via a simulation study suggests is due to non‐contact and refusal having largely different predictors.     

The distributive and welfare effects of product and labour market deregulation

This paper studies the effects of product and labour market deregulation on wage inequality and welfare. By constructing an analytically tractable model in which the level of product market competition and the wages are endogenously distributed among sectors, I show that deregulation in goods market has mixed effects on inequality: the wage variance and the Gini index are lower, but the ratio of the highest over the lowest wage paid in the economy increases. Moreover, deregulation in labour markets raises the aggregate level of employment and the average real wage but reduces the welfare of trade unions in sectors with a low level of competition.     

The dynamic of innovation networks: a switching model on technological change

In this paper, we introduce an agent-based model where heterogeneous firms compare and modify their innovation strategies, so generating an evolving network structure. By implementing dynamic behavioral switching via a fitness mechanism based on agents’ performance, companies can endogenously modify their tactics for technological change and switch among three groups: stand-alone innovators, collaborative innovators and imitators. On the one hand, we study the properties of the emerging networks and we show that they reproduce the stylized facts of innovation networks. Moreover, we focus the analysis on the impact of these three innovation categories on the macro economic aggregate, finding that collaborative companies are those having the highest positive impact on the economic system. On the other hand, we use the model to study the effect of different economic innovation policies in increasing macroeconomic performance.     

Modelling Credit Risk for SMEs: Evidence from the U.S. Market

Considering the fundamental role played by small and medium sized enterprises (SMEs) in the economy of many countries and the considerable attention placed on SMEs in the new Basel Capital Accord, we develop a distress prediction model specifically for the SME sector and to analyse its effectiveness compared to a generic corporate model. The behaviour of financial measures for SMEs is analysed and the most significant variables in predicting the entities' credit worthiness are selected in order to construct a default prediction model. Using a logit regression technique on panel data of over 2,000 U.S. firms (with sales less than $65 million) over the period 1994–2002, we develop a one-year default prediction model. This model has an out-of-sample prediction power which is almost 30 per cent higher than a generic corporate model. An associated objective is to observe our model's ability to lower bank capital requirements considering the new Basel Capital Accord's rules for SMEs.