TESTING RESTRICTIONS IN NORMAL DATA MODELS USING GIBBS SAMPLING

The problem of testing a set of restrictions R(q)=0 in a complex hierarchical model is considered. We propose a different approach from the standard PO ratio test, which can be viewed as the Bayesian analogous to the classical Wald type test. With respect to the PO ratio, it has the advantage of being easier to implement and, unlike the PO ratio test, it can be computed also when some prior in the hierarchy is diffuse. Several Monte Carlo simulations show that the procedure scores very well both in terms of power and unbiasedness, generally doing as well as the standard PO ratio approach, or even better in cases where the degree of coefficient heterogeneity is not high.Linear restrictions, Gibbs sampling, Monte Carlo

Content Recarving as Subject Matter Restriction

In this article I offer an explicating interpretation of the procedure of content recarving as described by Frege in §64 of the Foundations of Arithmetic. I argue that the procedure of content recarving may be interpreted as an operation that while restricting the subject matter of a sentence, performs a generalization on what the sentence says about its subject matter. The characterization of the recarving operation is given in the setting of Yablo’s theory of subject matter and it is based on the relation of determination between properties. The main advantage of the proposal is its generality, for it is applicable not just to the case of abstraction principle

Collusion in Peer-to-Peer Systems

Peer-to-peer systems have reached a widespread use, ranging from academic and industrial applications to home entertainment. The key advantage of this paradigm lies in its scalability and flexibility, consequences of the participants sharing their resources for the common welfare. Security in such systems is a desirable goal. For example, when mission-critical operations or bank transactions are involved, their effectiveness strongly depends on the perception that users have about the system dependability and trustworthiness. A major threat to the security of these systems is the phenomenon of collusion. Peers can be selfish colluders, when they try to fool the system to gain unfair advantages over other peers, or malicious, when their purpose is to subvert the system or disturb other users. The problem, however, has received so far only a marginal attention by the research community. While several solutions exist to counter attacks in peer-to-peer systems, very few of them are meant to directly counter colluders and their attacks. Reputation, micro-payments, and concepts of game theory are currently used as the main means to obtain fairness in the usage of the resources. Our goal is to provide an overview of the topic by examining the key issues involved. We measure the relevance of the problem in the current literature and the effectiveness of existing philosophies against it, to suggest fruitful directions in the further development of the field

Monetary Policy Analysis in Real-Time. Vintage combination from a real-time dataset

This paper provides a general strategy for analyzing monetary policy in real time which accounts for data uncertainty without explicitly modelling the revision process. The strategy makes use of all the data available from a real-time data matrix and averages model estimates across all data releases. Using standard forecasting and policy models to analyze monetary authorities’ reaction functions, we show that this simple method can improve forecasting performance and provide reliable estimates of the policy model coe¢cients associated with small central bank losses, in particular during periods of high macroeconomic uncertainty.Monetary policy, Taylor rule, Real-time data, Great Moderation, Forecasting.

Estimating multi-country VAR models

This paper describes a methodology to estimate the coefficients, to test specification hypotheses and to conduct policy exercises in multi-country VAR models with cross unit interdependencies, unit specific dynamics and time variations in the coefficients. The framework of analysis is Bayesian: a prior flexibly reduces the dimensionality of the model and puts structure on the time variations; MCMC methods are used to obtain posterior distributions; and marginal likelihoods to check the fit of various specifications. Impulse responses and conditional forecasts are obtained with the output of MCMC routine. The transmission of certain shocks across G7 countries is analyzed. JEL Classification: C3, C5, E5Flexible priors, International transmission, Markov Chain Monte Carlo methods, Multi country VAR

Global inflation

This paper shows that inflation in industrialized countries is largely a global phenomenon. First, the inflation rates of 22 OECD countries have a common factor that alone accounts for nearly 70 percent of their variance. This large variance share that is associated with Global Inflation is not only due to the trend components of inflation (up from 1960 to 1980 and down thereafter) but also to fluctuations at business cycle frequencies. Second, we show that, in conformity to the prediction of New Keynesian open economy models, there is little spillover of inflationary shocks across countries. The comovement of inflation comes largely from common shocks. Global Inflation is a function of real developments at short horizons and monetary developments at longer horizons. Third, there is a robust "error correction mechanism" that brings national inflation rates back to Global Inflation. A simple model that accounts for this feature consistently beats the previous benchmarks used to forecast inflation 4 to 8 quarters ahead across samples and countries.Inflation (Finance)

Ship building and repairing in Italy, 1861-1913: national and regional time series

This paper presents the first comprehensive national and regional time-series estimates for ship building and repairing in post-Unification Italy. The path of the national aggregate differs markedly from the extant series, which cover merchant new-construction alone. The regional estimates point to considerable concentration: Liguria accounted for more than half the product, and Campania for almost another quarter. In Liguria, too, this sector represented up to a quarter of total industrial production; elsewhere, and nationally, it was barely significant.Italy, ship building industry, national and regional value added, 1861-1913

ClubMed? Cyclical fluctuations in the Mediterranean basin

We investigate macroeconomic fluctuations in the Mediterranean basin, their similarities and convergence. A model with four indicators, roughly covering the West, the East and the Middle East and the North Africa portions of the Mediterranean, characterizes well the historical experience since the early 1980. Idiosyncratic causes still dominate domestic cyclical fluctuations in many countries. Convergence and divergence coexist are local and transitory. The cyclical outlook for the next few years is rosier for the East than for the West.Bayesian Methods; Business cycles; Mediterranean basin; Developing and developed countries.

The Effects of Monetary Policy on Unemployment Dynamics Under Model Uncertainty. Evidence from the US and the Euro Area

This paper explores the role that the imperfect knowledge of the structure of the economy plays in the uncertainty surrounding the effects of rule-based monetary policy on unemployment dynamics in the euro area and the US. We employ a Bayesian model averaging procedure on a wide range of models which differ in several dimensions to account for the uncertainty that the policymaker faces when setting the monetary policy and evaluating its effect on real economy. We find evidence of a high degree of dispersion across models in both policy rule parameters and impulse response functions. Moreover, monetary policy shocks have very similar recessionary effects on the two economies with a different role played by the participation rate in the transmission mechanism. Finally, we show that a policy maker who does not take model uncertainty into account and selects the results on the basis of a single model may come to misleading conclusions not only about the transmission mechanism, but also about the differences between the euro area and the US, which are on average essentially small.Monetary policy, Model uncertainty, Bayesian model averaging, Unemployment gap, Taylor rule

Inflation Forecasts, monetary policy and unemployment dynamics: evidence from the US and the euro area

This paper explores the role that inflation forecasts play in the uncertainty surrounding the estimated effects of alternative monetary rules on unemployment dynamics in the euro area and the US. We use the inflation forecasts of 8 competing models in a standard Bayesian VAR to analyse the size and the timing of these effects, as well as to quantify the uncertainty relative to the different inflation models under two rules. The results suggest that model uncertainty can be a serious issue and strengthen the case for a policy strategy that takes into account several sources of information. We find that combining inflation forecasts from many models not only yields more accurate forecasts than those of any specific model, but also reduces the uncertainty associated with the real effects of policy decisions. These results are in line with the model-combination approach that central banks already follow when conceiving their strategy. JEL Classification: C53, E24, E37E24, E37, Inflation forecasts, JEL Classification: C53, Model uncertainty, Unemployment