Default prior choices fixing Zellner's g are predominant in the Bayesian Model Averaging literature, but tend to concentrate posterior mass on a tiny set of models. The paper demonstrates this supermodel effect and proposes to address it by a hyper-g prior, whose data-dependent shrinkage adapts...

This Selected Issues Paper on Iran reviews that monetary factors are the main determinants of inflation in the country. Government spending out of oil revenues leads to large liquidity injections that the central bank accommodates owing to its efforts to prevent a significant nominal...

We show the importance of a dynamic aggregation bias in accounting for the PPP puzzle. We prove that established time-series and panel methods substantially exaggerate the persistence of real exchange rates because of heterogeneity in the dynamics of disaggregated relative prices. When...

“Program numbers” from a sample of IMF-supported programs are studied as if they were forecasts, through statistical analyses of the relationship between projections and outcomes for growth, inflation, and three balance of payments concepts. Statistical bias is found only for projections of...

A simple criterion based on the properties of the forecast error is presented to evaluate the accuracy of forecasts. The efficiency conditions of an optimization problem are used to show that under rational expectations the standard statistical conditions are necessary, but not sufficient to...

In a recent paper, Bai and Perron (2006) demonstrate that their approach for testing for multiple structural breaks in time series works well in large samples, but they found substantial deviations in both the size and power of their tests in smaller samples. We propose modifying their...

This Selected Issues paper analyzes the sources of Mexico’s economic growth since the 1960s, and compares various decompositions of historical growth into trend and cyclical components. The role of the implied output gaps in the inflation process is assessed. The paper presents...

This paper provides a selective overview of nonlinear exchange rate models recently proposed in the literature and assesses their contribution to understanding exchange rate behavior. Two key questions are examined. The first question is whether nonlinear autoregressive models of real exchange...

Univariate studies of the hypothesis of unit roots in real exchange rates have yielded consensus point estimates of the half-life of deviations from purchasing power parity of between three to five years. However, least squares-based estimates of half-lives are biased downward. Accordingly, we...

The paper presents a comparative analysis of macroeconomic dynamics of 18 Arab countries based on a panel vector autogression estimation. Comparing growth performance, fiscal and current account developments in these countries, the study concludes that (1) in the short run, external and...