Jan J. J. Groen

Real-Time Inflation Forecasting in a Changing World

This paper revisits inflation forecasting using reduced-form Phillips curve forecasts, that is, inflation forecasts that use activity and expectations variables. We propose a Phillips-curve-type model that results from averaging across different regression specifications selected from a set of potential predictors. The set of predictors includes lagged values of inflation, a host of real-activity data, term structure data, nominal data, and surveys. In each individual specification, we allow for stochastic breaks in regression parameters, where the breaks are described as occasional shocks of random magnitude. As such, our framework simultaneously addresses structural change and model uncertainty that unavoidably affect Phillips-curve-based predictions. We use this framework to describe personal consumption expenditure (PCE) deflator and GDP deflator inflation rates for the United States in the post-World War II period. Over the full 1960-2008 sample, the framework indicates several structural breaks across different combinations of activity measures. These breaks often coincide with policy regime changes and oil price shocks, among other important events. In contrast to many previous studies, we find less evidence of autonomous variance breaks and inflation gap persistence. Through a real-time out-of-sample forecasting exercise, we show that our model specification generally provides superior one-quarter-ahead and one-year-ahead forecasts for quarterly inflation relative to an extended range of forecasting models that are typically used in the literature.

Commodity Prices, Commodity Currencies, and Global Economic Developments

In this paper, we seek to produce forecasts of commodity price movements that can systematically improve on naive statistical benchmarks. We revisit how well changes in commodity currencies perform as potential efficient predictors of commodity prices, a view emphasized in the recent literature. In addition, we consider different types of factor-augmented models that use information from a large data set containing a variety of indicators of supply and demand conditions across major developed and developing countries. These factor-augmented models use either standard principal components or the more novel partial least squares (PLS) regression to extract dynamic factors from the data set. Our forecasting analysis considers ten alternative indices and sub-indices of spot prices for three different commodity classes across different periods. We find that, of all the approaches, the exchange-rate-based model and the PLS factor-augmented model are more likely to outperform the naive statistical benchmarks, although PLS factor-augmented models usually have a slight edge over the exchange-rate-based approach. However, across our range of commodity price indices we are not able to generate out-of-sample forecasts that, on average, are systematically more accurate than predictions based on a random walk or autoregressive specifications.

Investigating the Structural Stability of the Phillips Curve Relationship

The reduced-form correlation between inflation and measures of real activity has changed substantially for the main developed economies over the post-WWII period. In this paper we attempt to describe the observed inflation dynamics in the United Kingdom, the United States and the euro area with a sequence of New Keynesian Phillips Curve (NKPC) equations that are log-linearised around different, non-zero, steady-state inflation levels. In doing this, we follow a two-step estimation strategy. First, we model the time variation in the relationship between inflation and a real cost-based measure of activity through a Markov-switching vector autoregressive model. We then impose the cross-equation restrictions of a Calvo pricing-based NKPC under non-zero steady-state inflation and estimate the structural parameters by minimising for each inflation state the distance between the restricted and unrestricted vector autoregressive parameters. The structural estimation results indicate that for all the economies there is evidence for a structurally invariant NKPC, albeit with a significant backward-looking component.

Real Exchange Rate Persistence and Systematic Monetary Policy Behaviour

This paper estimates forward-looking monetary policy rules for Germany over the 1979-98 period and for the United Kingdom for the periods 1979-90 and 1992-98. The estimation results indicate that there were substantial differences between systematic monetary policy in Germany and in the United Kingdom, as well as shifts in systematic monetary policy in the United Kingdom, over this period. The paper analyses the implications of these estimated policy rules for real exchange rate behaviour in an open economy dynamic stochastic general equilibrium model. The analysis shows that real exchange rate persistence could be attributed to the persistence of real shocks and interest rate smoothing behaviour of central banks. However, the observed cross-country asymmetry in systematic monetary policy behaviour elevates real exchange rate persistence to realistic levels, whereas changes in asymmetric policy behaviour alter the character of real exchange rate persistence.

Real Exchange Rates and the Relative Prices of Non-traded and Traded Goods: An Empirical Analysis

This paper provides an empirical analysis of the decomposition of UK real exchange rates into the relative price of traded goods and the ratio of the relative price of non-traded to traded goods, and tests the prediction that deviations from the law of one price in tradable goods dominate real exchange rate variability only in the short run. UK bilateral real exchange rates are examined relative to a sample of six main OECD partners. The existence of a long-run relationship between real exchange rates and these corresponding relative price ratios is analysed using cointegrated vector autoregressive models. These show only limited evidence of a cointegrating relationship. The paper quantifies the severity of the deviations from the law of one price, and shows that these deviations are persistent relative to the length of the sample period. This motivates the use of a multi-country panel cointegration-testing framework, which produces evidence of a long-run relationship between the real exchange rate and the non-tradable component.

Time-Varying Inflation Expectations and Economic Fluctuations in the United Kingdom: A Structural VAR Analysis

This paper examines how the interaction between inflation expectations and nominal and real macroeconomic variables has evolved for the United Kingdom over the post-WWII period until 2007. We model time-variation through a Markov-switching structural vector autoregressive framework with variants of the sign restriction identification scheme to back out the time-varying effect of different structural shocks. We investigate the following questions: (i) How has the impact of the mix of real and nominal shocks on the UK economy evolved over time and did this have a specific impact on UK inflation expectations? and (ii) Has there been an autonomous impact of inflation expectations on the UK economy and has it changed over time? Our results suggest that shocks to inflation expectations had important effects on actual inflation in the 1970s, but this impact had significantly declined towards the end of our sample. This seems to be mainly due to a relatively slower response of monetary policy to these shocks in the 1970s compared to later years. Similarly, oil price shocks and real demand shocks led to important changes in macroeconomic variables in the 1970s. Beyond that period and up to the end of our sample oil price shocks became less significant for the dynamics of actual inflation and output growth. However real demand shocks became a relatively more important determinant for fluctuations in those series during the 1990s and the beginning of the 2000s. The changing response of monetary policy to this type of shock appears to be crucial for this result.

Parsimonious Estimation with Many Instruments

We suggest a way to perform parsimonious instrumental variables estimation in the presence of many, and potentially weak, instruments. In contrast to standard methods, our approach yields consistent estimates when the set of instrumental variables complies with a factor structure. In this sense, our method is equivalent to instrumental variables estimation that is based on principal components. However, even if the factor structure is weak or nonexistent, our method, unlike the principal components approach, still yields consistent estimates. Indeed, simulations indicate that our approach always dominates standard instrumental variables estimation, regardless of whether the factor relationship underlying the set of instruments is strong, weak, or absent.

New Multi-Country Evidence on Purchasing Power Parity: Multivariate Unit Root Test Results

In this paper a likelihood-based multivariate unit root testing framework is utilized to test whether the real exchange rates of G10 countries are non-stationary. The framework uses a likelihood ratio statistic which combines the information across all involved countries while retaining heterogeneous rates of mean reversion. This likelihood ratio statistic has an asymptotic distribution which can be typified as a summation of squared, univariate Dickey and Fuller (1979) distributions. Our multivariate unit root tests indicate that bilateral G10 real exchange rates are stationary, irrespective of the numeraire country. We also analyze per panel the time necessary to have an adjustment to a shock in the individual real exchange rates. From this analysis it becomes apparent that there are significant cross-country differences in the adjustment of individual real exchange rates within each panel.