Jacek Suda

Learning Leverage Shocks and the Great Recession

This paper develops a simple business-cycle model in which financial shocks have large macroeconomic effects when private agents are gradually learning their economic environment. When agents update their beliefs about the unobserved process driving financial shocks to the leverage ratio, the responses of output and other aggregates under adaptive learning are significantly larger than under rational expectations. In our benchmark case calibrated using US data on leverage, debt-to-GDP and land value-to-GDP ratios for 1996Q1-2008Q4, learning amplifies leverage shocks by a factor of about three, relative to rational expectations. When fed with the actual leverage innovations, the learning model predicts the correct magnitude for the Great Recession, while its rational expectations counterpart predicts a counter-factual expansion. In addition, we show that procyclical leverage reinforces the impact of learning and, accordingly, that macro-prudential policies enforcing countercyclical leverage dampen the effects of leverage shocks. Finally, we illustrate how learning with a misspecified model that ignores real/financial linkages also contributes to magnify financial shocks.

Belief shocks and the macroeconomy

I study the role of shocks to beliefs combined with Bayesian learning in a standard equilibrium business cycle framework. By adapting ideas from Cogley and Sargent (2008b) to the general equilibrium setting, I am able to study how a prior belief arising from the Great Depression may have influenced the macroeconomy during the last 75 years. In the model, households hold twisted beliefs concerning the likelihood and persistence of recession and boom states, beliefs which are only gradually unwound during subsequent years. Even though the driving stochastic process for technology is unchanged over the entire period, the nature of macroeconomic performance is altered considerably for many decades before eventually converging to the rational expectations equilibrium. This provides some evidence of the lingering effects of beliefs-twisting events on the behavior of macroeconomic variables.

International Great Inflation and Common Monetary Policy

We study whether monetary authorities in the G7 countries were changing their responses to inflation in a similar manner during and following the Great Inflation era. We find that the common to the G7 countries inflation pattern during the Great Inflation period could be associated with a common pattern in the monetary policy response to inflation: we find that until the early 1980s monetary authorities in the G7 countries responded mildly to inflation, systematically fought it throughout the 1980s and lessened again their response during the 2000s. The estimated Taylor rule coefficients on inflation are cointegrated, implying the existence of a long run relation- ship in the responses to inflation during and after the Great Inflation period. At the same time, principal component analysis of the residuals of the estimated Taylor rules indicates that the shocks’ structure cannot account enough for the monetary policies’ comovements. We interpret these findings as suggestive of common monetary policy patterns.

The Stability of Macroeconomic Systems with Bayesian Learners

We study abstract macroeconomic systems in which expectations play an important role. Consistent with the recent literature on recursive learning and expectations, we replace the agents in the economy with econometricians. Unlike the recursive learning literature, however, the econometricians in the analysis here are Bayesian learners. We are interested in the extent to which expectational stability remains the key concept in the Bayesian environment. We isolate conditions under which versions of expectational stability conditions govern the stability of these systems just as in the standard case of recursive learning. We conclude that Bayesian learning schemes, while they are more sophisticated, do not alter the essential expectational stability findings in the literature.