Managing Disinflation under Uncertainty

In this paper we analyze disinflation policy when a central bank has imperfect information about private sector inflation expectations but learns about them from economic outcomes, which are in part the result of the disinflation policy itself. The form of uncertainty is manifested as uncertainty about the effect ofpastdisinflation policy on the current output gap. This differs from other studies on learning and control in a monetary policy context (e.g. Ellison (2006) and Svensson and Williams (2007)) that assume uncertainty about the effects of current policy actions on the economy. We derive the central bank's optimal disinflation strategy under active learning (DOP) and compare it with two limiting cases - certainty equivalence policy (CEP), or passive learning, and a Brainard-style cautionary monetary policy (CP). It turns out that under the DOP inflation stays between the levels implied by the CEP and the CP. A novel result - e.g. unlike Beck and Wieland (2002)| is that this holds irrespective of the initial level of inflation. At high levels of inherited inflation the DOP moves closer to the CEP, at low levels of inherited inflation the DOP resembles the CP.Learning, Inflation Expectations, Disinflation Policy, Separation Principle, Kalman Filter, Optimal Control, Dynamic Programming

Learning About the Term Structure and Optimal Rules for Inflation Targeting

n this paper we incorporate the term structure of interest rates in a standard inflation forecast targeting framework. We find that under flexible inflation targeting and uncertainty in the degree of persistence in the economy, allowing for active learning possibilities has effects on the optimal interest rate rule followed by the central bank. For a wide range of possible initial beliefs about the unknown parameter, the dynamically optimal rule is in general more activist, in the sense of responding aggressively to the state of the economy, than the myopic rule for small to moderate deviations of the state variable from its target. On the other hand, for large deviations, the optimal policy is less activist than the myopic and the certainty equivalence policies.

Trend growth and learning about monetary policy rules in a two-block world economy

Available evidence supports the view that growth is faster in more open economies. In order to analyze the implications of openness and growth on determinacy and learnability of worldwide rational expectations equilibria we develop a two-country New Keynesian model with growth. We analyze these issues for contemporaneous data and expectations-based monetary policy rules. Our results highlight how growth matters for the overall effect of opening an economy to more trade, as we find that (i) under the contemporaneous data policy rule the conditions for determinacy and learnability become more stringent on account of openness but less stringent on account of growth, so that growth weakens the effect of openness, (ii) under the expectations-based policy rule the conditions for determinacy and learnability also become more stringent on account of openness while on account growth the conditions for determinacy become more stringent (thus reinforcing the effect of openness) but those for learnability become less stringent (thus weakening the effect of openness). As in Bullard and Schaling (2009) the elasticity of intertemporal substitution is key to our result but within a framework that is consistent with long-run labor supply and balanced growth facts

Managing disinflation under uncertainty

In this paper we analyze disinflation policy when a central bank has imperfect information about private sector inflation expectations but learns about them from economic outcomes, which are in part the result of the disinflation policy. The form of uncertainty is manifested as uncertainty about the effect of past disinflation policy on current output gap. Thus current as well as past policy actions matter for output gap determination. We derive the optimal policy under learning (DOP) and compare it two limiting cases---certainty equivalence policy (CEP) and cautionary policy (CP). It turns out that under the DOP inflation stay between the levels implied by the CEP and the CP. A novel result is that this holds irrespective of the initial level of inflation. Moreover, while at high levels of inherited inflation the DOP moves closer to the CEP, at low levels of inherited inflation the DOP resembles the CP.In this paper we analyze disinflation policy when a central bank has imperfect information about private sector inflation expectations but learns about them from economic outcomes, which are in part the result of the disinflation policy. The form of uncertainty is manifested as uncertainty about the effect of past disinflation policy on current output gap. Thus current as well as past policy actions matter for output gap determination. We derive the optimal policy under learning (DOP) and compare it two limiting cases---certainty equivalence policy (CEP) and cautionary policy (CP). It turns out that under the DOP inflation stay between the levels implied by the CEP and the CP. A novel result is that this holds irrespective of the initial level of inflation. Moreover, while at high levels of inherited inflation the DOP moves closer to the CEP, at low levels of inherited inflation the DOP resembles the CP. -- Learning ; inflation expectations ; disinflation policy ; separation principle ; Kalman filter ; optimal contro

On determinacy and learnability in a New Keynesian model with unemployment

We analyze determinacy and stability under learning (E-stability) of rational expectations equilibria in the Blanchard and Galí (2006, 2008) New-Keynesian model of inflation and unemployment, where labor market frictions due to costs of hiring workers play an important role. We derive results for alternative specifications of monetary policy rules and alternative values of hiring costs as a percentage of GDP. Under low hiring costs - a typical part of the U.S. calibration - for policy rules based on current period inflation and unemployment our results are similar to those of Bullard and Mitra (2002). However, we find that the region of indeterminacy and E-instability in the policy space increases with the hiring costs. So, higher hiring costs - consistent with the European 'sclerotic' labor market institutions - seem to play an important part in explaining unemployment instability. Under lagged data based rules the area where monetary policy delivers both determinacy and E-stability shrinks. These rules perform worse according to these two dimensions when hiring costs go up. Finally, under expectations-based rules - unlike Bullard and Mitra (2002) - an additional explosive region is introduced. Here also the scope for determinacy and E-stability oriented monetary policy decreases. Interestingly - under the same rule and European 'sclerotic' labor market institutions we find that responding too much to expected inflation and too little to expected unemployment may very well be self-defeating. When hiring costs are large, a central bank that follows such a policy rule could very easily end up in the worst-case scenario of both indeterminacy and E-instability

Measuring Central Bank Independence: Ordering, Ranking, or Scoring?

Central bank independence (CBI)as an area for international comparison and for study by international political economists has been around for approximately two decades, spurred on by the work of Bade and Parkin (1982). It probably reached its full fruition with the work of Cukierman and others, centering on work done at the World Bank. There are others too, and we should not ignore them, but since the mid-1990s most of the work done has centered on the Cukierman-type model. Interest in the CBI intensified after models of monetary policy found the likelihood of an inflationary bias in monetary policy operated by democratic governments. That analysis turned on the potential for monetary surprises being perpetrated by governments seeking electoral advantage. Later analysis found that if such incentives were fully anticipated by the public, inflation rates in democracies are higher than they would be if somehow government could make a credible commitment to price stability. The search began for how to establish monetary institutions that can be viewed as credible commitments. Delegation of monetary policy to an independent central bank was one strand of that exploration

On Determinacy and Learnability in a New Keynesian Model with Unemployment

We analyze determinacy and stability under learning (E-stability) of rational expectations equilibria in the Blanchard and Galí (2006, 2008) New-Keynesian model of inflation and unemployment, where labor market frictions due to costs of hiring workers play an important role. We derive results for alternative specifications of monetary policy rules and alternative values of hiring costs as a percentage of GDP. Under low hiring costs – a typical part of the U.S. calibration – for policy rules based on current period inflation and unemployment our results are similar to those of Bullard and Mitra (2002). However, we find that the region of indeterminacy and E-instability in the policy space increases with the hiring costs. So, higher hiring costs – consistent with the European 'sclerotic' labor market institutions – seem to play an important part in explaining unemployment instability. Under lagged data based rules the area where monetary policy delivers both determinacy and E-stability shrinks. These rules perform worse according to these two dimensions when hiring costs go up. Finally, under expectations-based rules – unlike Bullard and Mitra (2002) – an additional explosive region is introduced. Here also the scope for determinacy and E-stability oriented monetary policy decreases. Interestingly – under the same rule and European 'sclerotic' labor market institutions – we find that responding too much to expected inflation and too little to expected unemployment may very well be self-defeating. When hiring costs are large, a central bank that follows such a policy rule could very easily end up in the worst-case scenario of both indeterminacy and E-instabilityMonetary Policy Rules, Determinacy, Learning, E-Stability

Managing Disinflation under Uncertainty

In this paper we analyze disinflation policy when a central bank has imperfect information about private sector inflation expectations but learns about them from economic outcomes, which are in part the result of the disinflation policy. The form of uncertainty is manifested as uncertainty about the effect of past disinflation policy on current output gap. Thus current as well as past policy actions matter for output gap determination. We derive the optimal policy under learning (DOP) and compare it two limiting cases---certainty equivalence policy (CEP) and cautionary policy (CP). It turns out that under the DOP inflation stay between the levels implied by the CEP and the CP. A novel result is that this holds irrespective of the initial level of inflation. Moreover, while at high levels of inherited inflation the DOP moves closer to the CEP, at low levels of inherited inflation the DOP resembles the CPLearning, Inflation Expectations, Disinflation Policy, Separation Principle, Kalman Filter, Optimal Control