Ricardo Praca Cavaco Nunes

Learning the Inflation Target

The New Keynesian model with rational expectations unrealistically predicts that unanticipated credible changes in the inflation target lead to an immediate jump in the inflation level while the output gap is unaffected. We set up a theoretical model where agents learn the behaviour of the economy. In this context, a permanent change in the inflation target leads inflation to respond sluggishly while the output gap is temporarily affected. We extend the model to allow for both learners and forward looking agents to coexist. The calibrated model explains quite well transition dynamics during the Volker disinflation.

Political Disagreement, Lack of Commitment and the Level of Debt

We analyze how public debt evolves when successive policymakers have different policy goals and cannot make credible commitments about their future policies. We consider several cases to be able to disentangle and quantify the respective effects of imperfect commitment and political disagreement. Absent political turnover, imperfect commitment drives the long-run level of debt to zero. With political disagreement, debt is a sizeable fraction of GDP and increasing in the degree of polarization among parties, no matter the degree of commitment. The frequency of political turnover does not produce quantitatively relevant effects. These results are consistent with much of the existing empirical evidence. Finally, we find that in the presence of political disagreement the welfare gains of building commitment are lower.

Loose Commitment in Medium-Scale Macroeconomic Models: Theory and an Application

This paper proposes a method and a toolkit for solving optimal policy with imperfect commitment in linear quadratic models. As opposed to the existing literature, our method can be employed in medium- and large-scale models typically used in monetary policy. We apply our method to the Smets and Wouters (2007) model, where we show that imperfect commitment has relevant implications for the interest rate setting, the sources of business cycle fluctuations, and welfare.

On the Epidemiological Microfoundations of Sticky Information

We estimate and compare two models in which households periodically update their expectations. The first model assumes that households update their expectations towards survey measures. In the second model, households update their expectations towards rational expectations (RE). While the literature has used these specifications indistinguishably, we argue that there are important differences. The two models imply different updating probabilities, and the data seem to prefer the second one. We then analyse the properties of both models in terms of mean expectations, median expectations, and a measure of disagreement among households. The model with periodical updates towards RE also seems to fit the data better along these dimensions.

Simple Monetary Rules under Fiscal Dominance

This paper asks whether an aggressive monetary policy response to inflation is feasible in countries that suffer from fiscal dominance, as long as monetary policy also responds to fiscal variables. We find that if nominal interest rates are allowed to respond to government debt, even aggressive rules that satisfy the Taylor principle can produce unique equilibria. But following such rules results in extremely volatile inflation. This leads to very frequent violations of the zero lower bound on nominal interest rates that make such rules infeasible. Even within the set of feasible rules the optimal response to inflation is highly negative, and more aggressive inflation fighting is inferior from a welfare point of view. The welfare gain from responding to fiscal variables is minimal compared to the gain from eliminating fiscal dominance.

Delegation and Loose Commitment

This paper analyzes and compares the performance of different delegation schemes when the central bank has imperfect commitment. A continuum of loose commitment possibilities is considered ranging from full commitment to full discretion. The results show that the performance of inflation targeting improves substantially with higher commitment levels. On the other hand, the performance of other targeting regimes does not necessarily improve with the commitment level of the central bank. While it was previously thought that inflation targeting is inferior to other targeting regimes, the results show that it can be the best performing regime as long as the commitment level is not too low. These results may provide a theoretical explanation for the high popularity of inflation targeting among central banks.

Optimal Monetary Policy in a Heterogenous Expectations Framework

We consider a heterogenous expectations model where some agents are adaptive learners while others are rational. We consider three optimal monetary policy rules when the central bank either does not influence expectations or does influence expectations of learners or does influence expectations of learners and rational agents. We analyze a disinflation episode since this is a relevant policy setting to compare our rules. We find that there are non-negligible benefits from actively influencing expectations. Finally, we consider that the central bank may have wrong beliefs about the proportion of learners in the economy. We also find that these rules are safe to implement even when the central bank has misspecified beliefs.