Sulla nozione di riassunto esaustivo

Si studiano dal punto di vista formale (ponendosi in un quadro astratto molto generale) le relazioni tra la nozione di riassunto esaustivo «in senso classico» e quella di riassunto esaustivo «in senso bayesiano». In particolare si analizzano, per ciascuna di queste nozioni, le condizioni di validità della fattorizzazione di Neyman.

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Résumé On étudie d'un point de vue purement formel (en se plaçant dans un cadre abstrait très général) les relations entre la notion de résumé exhaustif «au sens classique» et celle de résumé exhaustif «au sens bayesien».On analyse notamment, pour chacune de ces deux notions, les conditions de validité de la factorisation de Neyman.

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Pubblichiamo volentieri questo articolo di G. Letta, che per l'impostazione astratta si allontana alquanto dall'ambito degli interessi scientifici di questa Rivista, perché l'argomento trattato è strettamente legato ad un lavoro di D. M. Cifarelli ed E. Regazzini recentemente comparso sul nostro periodico (vedi [3] e la 2^a parte in questo fascicolo).     

Is Social Security Really Bad for Growth?

This paper develops a model of endogenous growth with overlapping generations to investigate the joint determination of social security, public investment, and growth in a small open economy. We show that a pure pay-as-you-go system with benefits indexed to wages provides taxpayers with incentives to support growth-oriented policies, which increase the future productivity of labor. We find that outcomes characterized by positive levels of intergenerational redistribution, public investment, and long-run growth can be sustained as subgame-perfect Nash equilibria of an infinitely repeated intergenerational game, if and only if the marginal productivity of public capital is large enough. Furthermore, we show that transfers comove with public investment and growth. Journal of Economic Literature Classification Numbers: E62, H55.     

ON THE HIERARCHY OF SOME QUALITATIVE STRUCTURES IN THE VON NEUMANN AND RELATED MODELS

In this paper we collect some old and new qualitative-structural properties on the input and output matrices involved in the classical von Neumann model, properties relevant, from the formal and/or economic point of view, in the study of the equilibria of the said model. It is established the hierarchy, i.e. the relations of inclusion, partial overlapping and disjunction, among these properties, which permits to amend some current slips in the analysis of the von Neumann model (one due to von Neumann himself). The results obtained can be fitted to other production and exchange multisectorial models.     

Can Hedge Funds Time the Market?

We answer the somewhat narrower question of whether hedge funds adjust their conditional market exposure in response to real‐time changes in macroeconomic conditions, and whether doing so improves their performance. We find that hedge funds differ substantially in their responsiveness to macroeconomic data. The most procyclical market timers outperform their less active and counter‐cyclical peers by over 4% annualized with a risk adjusted alpha of 5.5%.     

Effects of the Adoption of IFRS on the Credit Market: Evidence from Brazil

Based on a sample of approximately 6500 credit ratings and 137,000 loan contracts, this paper analyzes the effects of mandatory IFRS adoption on the Brazilian credit market. We find that the IFRS adoption effects were limited to firms displaying improved accounting information quality at the time of transition, lending support to the notion that economic benefits do not necessarily flow from the publication of financial reports in IFRS but, rather, depend on how earnestly firms adopt the recommended disclosure practices.     

A dynamic exchange rate model with heterogeneous agents

In this paper, we analyze a heterogeneous agent model in which the fundamental exchange rate is endogenously determined by the real markets. The exchange rate market and the real markets are linked through the balance of payments. We have analytically found that there exists at least a steady state in which the exchange rate is equal to its fundamental value and incomes of both countries are equal to the autonomous components times the multiplier (as in the Income-Expenditure model). This steady state can be unique and unstable when all agents act as contrarians, while when agents act as fundamentalists it is unique but its stability depends on the reactivity of actors of the market. Finally, we show that the (in)stability of the economic system depends on both the reactivity of the markets and that of different types of agents involved. Employing well-know functional forms, we show that the model can replicate some of the statistical features of the true time series of the exchange rate.     

Dual Labour Market Intermediaries in Italy: How to Lay off “Lemons”—Thereby Creating a Problem of Adverse Selection

Using longitudinal data from the Bank of Italy that cover the period from 2004 to 2014, this paper investigates the wage- and career implications of temporary jobs across the entire wage profile via unconditional quantile regression models and dynamic panel probit models. Building on Autor’s contributions, we consider temporary jobs to be a Labour Market Intermediary that deals with job-matching problems, such as information asymmetries, search cost reductions, worker-side adverse selection, and pay-productivity gaps. Assuming that wage is a proxy for workers’ productivity, we examine the chances that temporary workers who are located in different quantiles of wage distribution have of making the transition towards a stable employment position in the primary labour market. Results clearly indicate that temporarily employed individuals suffer significant wage- and career penalties. Not only are these individuals overly concentrated in the lowest decile of wage distribution, but the career penalty associated with temporary jobs also remains stable independently of the wage/productivity quantile to which the workers belong. If firms use FTC or TWA at all, they do so to remove less productive workers, whose work contract is not renewed once expired. In light of this evidence, it is clear that the hypothesis—proposed in the economic literature—that temporary employment contracts might serve as a screening tool to identify the most productive workers who would then be offered a stable position in the primary labour market does not hold in the highly dualised labour market of Southern Europe.