Cointegration and the joint confirmation hypothesis

Recent papers by Charemza and Syczewska (1998) and Carrion, Sansó and Ortuño (2001) focused on the joint use of unit root and stationarity tests. In this paper, the discussion is extended to the case of cointegration. Critical values for testing the joint confirmation hypothesis of no cointegration are computed and a small Monte Carlo experiment evaluates the relative performance of this procedure.Cointegration; Joint confirmation hypothesis; Monte Carlo simulations.

Exploiting long-range disorder in slow-light photonic crystal waveguides

The interplay between order and disorder in photonic lattices opens up a wide range of novel optical scattering mechanisms, resonances, and applications that can be obscured by typical ordered design approaches to photonics. Striking examples include Anderson localization, random lasers, and visible light scattering in biophotonic structures such as butterfly wings. In this work, we present a profound example of light localization in photonic crystal waveguides by introducing long-range correlated disorder. Using a rigorous three-dimensional Bloch mode expansion technique, we demonstrate how inter-hole correlations have a negative contribution to the total out-of-plane radiative losses, leading to a pronounced enhancement of the quality factor, $Q$, and $Q/V$ cavity figures of merit in the long-range correlation regime. Subsequently, the intensity fluctuations of the system are shown to globally increase with the correlation length, highlighting the non-trivial role of long-range disorder on the underlying scattering mechanisms. We also explore the possibility of creating ultra-high quality cavity modes via inter-hole correlations, which have various functionalities in chip-based nonlinear optics and waveguide cavity-quantum electrodynamics.Comment: Updated version with DO

An Efficient Test of Fiscal Sustainability

We suggest a multivariate efficient test of the 'strong' fiscal sustainability hypothesis, based on Horvath and Watson's (1995) cointegration test when cointegration vectors are pre-specified. Using data for a set of developed and developing economies, we show that, unlike our procedure, conventional methodologies tend to penalize the sustainability hypothesis.

Monetary Policies in Interdependent Economies with Stochastic Disturbances: A Strategic Approach

This paper analyzes strategic monetary policies using a standard two country stochastic macro model. Three noncooperative equilibria, namely Cournot, Stackelberg, and Consistent Conjectural Variations, are considered.The Pareto Optimal equilibrium, where aggregate joint costs are minimizedis also considered, and all strategic equilibria are compared to the perfectly fixed and flexible exchange rate regimes. The main conclusions obtained are:(i) Demand shocks are much less problematical than supply disturbances from the viewpoint of macro stabilization; (ii) the gains from cooperation are typically small; (iii) the strategic equilibria all show substantial margins of superiority over the fixed and flexible regimes.

The Choice of Monetary Instrument in Two Interdependent Economies Under Uncertainty

This paper analyzes the choice of monetary instrument in a stochastic two country setting where each country's set of monetary policy instruments includes both the money supply and the interest rate. It shows how the optimal choice of instrument is determined In two stages. First, for each pair, the minimum welfare coat for each economy is determined This defines a par of payoff matrices and the second stage involves determining the Nash equilibrium for this bimatrix game. In our illustrative example for the alternative shocks considered, a dominant Nash equilibrium is always obtained.

The cost channel reconsidered: a comment using an identification-robust approach

We re-examine the empirical relevance of the cost channel of monetary policy (e.g. Ravenna and Walsh, 2006), employing recently developed moment-conditions inference methods, including identification-robust procedures. Using US data, our results suggest that the cost channel effect is poorly identified and we are thus unable to corroborate the previous results in the literature.Cost channel; Phillips curve; GMM; Generalized Empirical Likelihood; Weak Identification.

The Forecast Performance of Long Memory and Markov Switching Models

Recent research has focused on the links between long memory and structural change, stressing the long memory properties that may arise in models with parameter changes. In this paper, we contribute to this research by comparing the forecasting abilities of long memory and Markov switching models. Two approaches are employed: a Monte Carlo study and an empirical comparison, using the quarterly Consumer Price inflation rate in Portugal in the period 1968-1998. Although long memory models may capture some in-sample features of the data, when shifts occur in the series considered, their forecast performance is relatively poor, when compared with simple linear and Markov switching models. Moreover, our findings, in a more general framework, are in accordance with the works of Clements and Hendry (1998) and Clements and Krolzig (1998), reinforcing the idea that simple linear time series models remain useful tools for prediction.Long Memory; Structural change; Forecasting

The Properties of Cointegration Tests in Models with Structural Change

In this paper we examine, by means of Monte Carlo simulation, the properties of several cointegration tests when long run parameters are subject to structural changes. We allow for different types of stochastic and deterministic regime shifts, more specifically, changes governed by Markov chains, martingale parameter variation, sudden multiple breaks and gradual changes. Our Monte Carlo analysis reveals that tests with cointegration as the null hypothesis perform badly, while tests with the null of no cointegration retain much of their usefulness in this context.Structural change; Cointegration; Tests; Monte Carlo