Guido Ascari

© 2020, European Central Bank. All rights reserved. This paper studies the challenge that increasing the inflation target poses to equilibrium determinacy in a medium-sized New Keynesian model without indexation fitted to the Great Moderation era. For moderate targets of the inflation rate, such as 2 or 4 percent, the probability of determinacy is near one conditional on the monetary policy rule of the estimated model. However, this probability drops significantly conditional on model-free estimates of the monetary policy rule based on real-time data. The difference is driven by the larger response of the federal funds rate to the output gap associated with the latter estimates.

© 2019 Recently developed econometric methods, that are robust to weak instruments and exploit information in possible structural changes, are applied to study the Euler equation for consumption using aggregate US post-war data. Several extensions to the baseline Euler equation model are investigated. The results are insensitive to using linear versus nonlinear specifications, different instruments or different consumption data, but they are very sensitive to asset returns. With risk-free returns, the elasticity of intertemporal substitution is tightly estimated around zero, while with stock market returns, it is significantly positive but very imprecisely estimated. There is no evidence of parameter instability.

Recent empirical evidence identfies investment shocks as key driving forces behind business cycle fluctuations. However, existing New Keynesian models emphasizing these shocks counterfactually imply a negative unconditional correlation between consumption growth and investment growth, a weak positive unconditional correlation between consumption growth and output growth and anomalous profiles of cross-correlations involving consumption growth. These anomalies arise because of a short-run contractionary effect a positive investment shock on consumption. Such counterfactual co-movements are typical of the "Barro-King curse" (Barro and King 1984), wherein models with a real business cycle core must rely on technology shocks to account for the observed co-movement among output, consumption, investment, and hours. We show that two realistic additions to an otherwise standard medium scale New Keynesian model - namely, roundabout production and real per capita output growth stemming from trend growth in neutral and investment-specific technologies - can break the Barro-King curse and provide a more accurate account of unconditional business cycle comovements more generally. These two features substantially magnify the effects of neutral technology and investment shocks on aggregate fluctuations and generate a rise of consumption on impact of a positive investment shock.

Abstract The instability of macroeconomic variables is usually ruled out by rational expectations. We propose a generalization of the rational expectations framework to estimate possible temporary unstable paths. Our approach yields drifting parameters and stochastic volatility. The methodology allows the data to choose between different possible alternatives: determinacy, indeterminacy and instability. We apply our methodology to US inflation dynamics in the ‘70s through the lens of a simple New Keynesian model. When unstable RE paths are allowed, the data unambiguously select them to explain the stagflation period in the ‘70s.Thus, our methodology suggests that US inflation dynamics in the ‘70s is better described by unstable rational equilibrium paths.