By Patrick Hürtgen
This paper explores the importance of shocks to consumer misperceptions, or “noise shocks”, in a quantitative business cycle model. I embed imperfect information as in Lorenzoni (2009) into a new Keynesian model with price and wage rigidities. Agents learn about the components of labor productivity by only observing aggregate productivity and a noisy signal. Noise shocks lead to expectational errors about the true fundamentals triggering aggregate fluctuations. Estimating the model with Bayesian methods on US data shows that noise shocks contribute to 20 percent of consumption fluctuations at short horizons. Wage rigidity is pivotal for the importance of noise shocks.
We are probably experiencing very large noise shocks these days. Maybe this paper can help us understand what is going on. Too bad there is no capital in the model, which could have given us some hints about the current stock market behavior.