Learning to forecast in macroexperiments


Speaker:Cars Hommes, University of Amsterdam
Date: Friday 13 December 2013
Time: 16.15 - 17.45
Location: Bateman Lecture Theatre, Building One, Streatham Campus

Further details

Seminar is based on two papers, the abstracts of both are below:

Individual Expectations and Aggregate Macro Behavior

The way in which individual expectations shape aggregate macroeconomic variables is crucial for the transmission and effectiveness of monetary policy. We study the individual expectations formation process and the interaction with monetary policy, within a standard New Keynesian model, by means of laboratory experiments with human subjects. Three aggregate outcomes are observed: convergence to some equilibrium level, persistent oscillatory behaviour and oscillatory convergence. We fit a heterogeneous expectations model with a performance-based evolutionary selection among heterogeneous forecasting heuristics to the experimental data. A simple heterogeneous expectations switching model fits individual learning as well as aggregate macro behaviour and outperforms homogeneous expectations benchmarks. Moreover, in accordance to theoretical results in the literature on monetary policy, we find that an interest rate rule that reacts more than point for point to inflation has some stabilizing effects on inflation in our experimental economies, although convergence can be slow in presence of evolutionary learning.

Evolutionary Selection of Individual Expectations and Aggregate Outcomes in Asset Pricing Experiments

In recent “learning to forecast” experiments (Hommes et al. 2005), three different patterns in aggregate price behavior have been observed: slow monotonic convergence, permanent oscillations, and dampened fluctuations. We show that a simple model of individual learning can explain these different aggregate outcomes within the same experimental setting. The key idea is evolutionary selection among heterogeneous expectation rules, driven by their relative performance. The out-of-sample predictive power of our switching model is higher compared to the rational or other homogeneous expectations benchmarks. Our results show that heterogeneity in expectations is crucial to describe individual forecasting and aggregate price behaviour.