Adam Honig

Extending the Textbook Dynamic AD-AS Framework with Flexible Inflation Expectations, Optimal Policy Response to Demand Changes, and the Zero-Bound on the Nominal Interest Rate

Many popular macroeconomics textbooks have recently adopted the dynamic aggregate demand – aggregate supply framework to analyze business cycle fluctuations and the effects of monetary policy. This brings the textbook treatment much closer to the research frontier, although one major difference is the treatment of inflation expectations. Textbook treatments typically assume adaptive expectations for tractability. In this paper, we incorporate a more flexible form of expectation formation by allowing it to be determined as a weighted average of past inflation and the inflation target. This brings the treatment closer to rational expectations and allows for a discussion of costless disinflation. Monetary policy is assumed to follow a Taylor rule, but we allow for deviations from the rule to motivate a discussion regarding optimal monetary policy response to demand shocks. We also include a shock to the risk-premium on the interest rate relevant for demand relative to the policy rate set by the Central Bank, and impose the zero bound on the nominal interest rate in the solution of the model. We use these features to motivate a discussion regarding the recent financial crisis, monetary policy falling into a liquidity trap, and the desirability of a temporary increase in the inflation target. Finally, we make available an Excel sheet with which students can analyze the effect of shocks to the economy using impulse responses and dynamic aggregate demand – aggregate supply diagrams.

A Model of Liability Dollarization and Myopic Governments

Abstract Liability dollarization of the domestic banking system represents a source of vulnerability for emerging market countries. The root cause is a lack of faith in the domestic currency, which ultimately stems from the belief that the government will not follow policies that promote long-run currency stability. This paper presents a model in which government myopia determines the unofficial dollarization of bank credit. Specifically, myopic politicians will choose low interest rates to expand short-run output in order to get re-elected, but this choice has the long-run consequence of increasing dollar lending. Increased liability dollarization is shown to force the hand of future decision-makers into choosing fixed exchange rates because of the fear that large depreciations will destroy balance sheets. The results imply that institutional reforms are necessary to reverse liability dollarization.