Is There More than One Way to be E-Stable?

We initially examine two different methods for learning about parameters in a Rational Expectations setting, and show that there are conflicting E-stability results. We show that this conflict also extends to Minimum State Variable (MSV) representations. One of these methods of learning lends itself to the examination of E-stability for the generic forward-looking rational expectations model. This leads to a completely general relationship between saddlepath stability and E-stability, and a generalization of MSV results.E-stability, Minimum state variable.

Saddlepath Learning

Saddlepath learning occurs when agents know the form but not the coefficients of the sad?dlepath relationship defining rational expectations equilibrium. Under saddlepath learning, we obtain a completely general relationship between determinacy and e-stability, and generalise Min?imum State Variable results previously derived only under full information. When the system is determinate, we show that a learning process based on the saddlepath is always e-stable. When the system is indeterminate, we find there is a unique MSV solution that is iteratively e-stable. However, in this case there is a sunspot solution that is learnable as well. We conclude by demon?strating that our results hold for any information set.e-stability, determinacy, learning, saddlepath stability.

Computation of LQ Approximations to Optimal Policy Problems in Different Information Settings under Zero Lower Bound Constraints

This paper describes a series of algorithms that are used to compute optimal policy under full and imperfect information. Firstly we describe how to obtain linear quadratic (LQ) approximations to a nonlinear optimal policy problem. We develop novel algorithms that are required as a result of having agents with forward-looking expectations, that go beyond the scope of those that are used when all equations are backward-looking; these are utilised to generate impulse response functions and second moments for the case of imperfect information. We describe algorithms for reducing a system to minimal form that are based on conventional approaches, and that are necessary to ensure that a solution for fully optimal policy can be computed. Finally we outline a computational algorithm that is used to generate solutions when there is a zero lower bound constraint for the nominal interest rate.

Robust Monetary Rules under Unstructured and Structured Model Uncertainty

This paper compares two contrasting approaches to robust monetary policy design. The first developed by Hansen and Sargent (2003, 2007) assumes unstructured model uncertainty and uses a minimax robustness criterion to design monetary rules. This contrasts with an older literature that structures uncertainty by seeking rules that are robust across competing views of the economy. This paper carries out and compares robust design exercises using both approaches using a standard ‘canonical New Keynesian model’. We pay particular attention to a number of issues: First, we distinguish three possible forms of the implied game between malign nature and the policymaker in the Hansen-Sargent procedure. Second, in both approaches, we examine the consequences for robust rules of the zero lower bound (ZLB) constraint on the nominal interest rate, the monetary instrument. Finally, again for both types of robustness exercise we explore the implications of policy design when the policymaker is obliged to use simple Taylor-type interest rate rules.robustness, structured and unstructured uncertainty, zero lower bound interest rate constraint

Internal description of multilinear systems

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Monetary and Fiscal Policy in a DSGE Model of India.

We develop a optimal rules-based interpretation of the 'three pillars macroeconomic policy framework': a combination of a freely floating exchange rate, an explict target for inflation, and a mechanism than ensures a stable government debt-GDP ratio around a specified long run. We show how such monetary-fiscal rules need to be adjusted to accommodate specific features of emerging market economies.The model takes the form of two-blocs, a DSGE emerging small open economy interacting with the rest of the world and features, in particular, financial frictions. It is calibrated using India and US data. Alongside the optimal Ramsey policy benchmark, we model the three pillars as simple monetary and fiscal rules including and both domestic and CPI inflation targeting interest rate rules. A comparison with a fixed exchange rate regime is ade. We find that domestic inflation targeting is superior to partially or implicitly (through a CPI inflation target) or fully attempting to stabilizing the exchange rate. Financial frictions require fiscal policy to play a bigger role and lead to an increase in the costs associated with simple rules as opposed to the fully optimal policy. These policy prescriptions contrast with the monetary-fiscal policy stance of the Indian authorities.Monetary policy ; Emerging economies ; Fiscal and monetary rules ; Financial accelerator ; Liability dollarization

Robust Inflation-Targeting Rules and the Gains from International Policy Coordination

This paper empirically assesses the performance of interest-rate monetary rules for interdependent economies characterized by model uncertainty. We set out a two-bloc dynamic stochastic general equilibrium model with habit persistence (that generates output persistence), Calvo pricing and wage-setting with indexing of non-optimized prices and wages (generating inflation persistence), incomplete financial markets and the incomplete pass-through of exchange rate changes. We estimate a linearized form of the model by Bayesian maximum-likelihood methods using US and Euro-zone data. From the estimates of the posterior distributions we then examine monetary policy conducted both independently and cooperatively by the Fed and the ECB in the form of robust inflation-targeting interest-rate rules. Comparing the utility outcome in a closed-loop Nash equilibrium with the outcome from a coordinated design of policy rules, we find a new result: the gains from monetary policy coordination rise significantly when CPI inflation targeting interest-rate rules are designed to account for model uncertainty.monetary policy coordination, robustness, inflation-targeting interest-rate rules.

Inflation, Human Capital and Tobin's q

A pervasive empirical finding for the US economy is that inflation is negatively correlated with the normalized market price of capital (Tobin's q) and growth. A dynamic stochastic general equilibrium model of endogenous growth is developed to explain these stylized facts. In this model, human capital is the principal driver of self-sustained growth. Long run comparative statics analysis suggests that inflation diverts scarce time resource to leisure which lowers human capital utilization. This impacts growth adversely and modulates cap¬ital adjustment cost downward resulting in a decline in Tobin's q. For the short run, a Tobin effect of inflation on growth weakens the negative association between inflation and q.

The Credibility Problem Revisited: Thirty Years on from Kydland and Prescott

Macroeconomics research has changed profoundly since the Kydland-Prescott seminal paper. In order to address the Lucas Critique, modelling now is based on microfoundations treating agents as rational utility optimizers. Bayesian estimation has produced models which are more data consistent than those based simply on calibration. With micro-foundations and new linear-quadratic techniques, normative policy based on welfare analysis is now possible. In the open economy, policy involves a ‘game’ with policymakers and private institutions or private individuals as players. This paper attempts to reassess the Kydland-Prescott contribution in the light of these developments.Monetary rules, commitment, discretion, open economy, coordination gains.

Fiscal Policy in a Monetary Union: Can Fiscal Cooperation be Counterproductive?

We analyze the interaction of monetary and fiscal policies in a monetary union where the common central bank is more conservative than the fiscal authorities. When monetary and fiscal policies are discretionary, we find that the Nash equilibrium is sub-optimal with higher output and lower inflation than the cooperative Ramsey op- timum. In a further example of counterproductive cooperative, we find that fiscal cooperation makes matters worse. We also examine cooperative and non-cooperative fiscal policy in the case where the central bank can commit and has the same prefer- ences as the fiscal authorities.fiscal-monetary policy interactions, fiscal cooperation and non-cooperation.