Learning,Monetary Policy,and Asset Prices

We explore the stability properties of interest rate rules granting an explicit response to stock prices in a New Keynesian DSGE model where the presence of non‐Ricardian households makes stock prices nonredundant for the business cycle. We find that responding to stock prices enlarges the policy space for which the equilibrium is both determinate and E‐stable (learnable). In particular, the Taylor principle ceases to be necessary, and determinacy/E‐stability is granted also by mildly passive policy rules. Our results appear to be more prominent in economies featuring a lower elasticity of substitution across differentiated products and/or more rigid labor markets.     

Learnability and monetary policy: A global perspective

The recent literature on monetary policy design has emphasized the importance of equilibrium determinacy and learnability in the choice of policy rules. This paper contains an analysis of the learnability of the equilibrium in a class of simple, micro-founded models in which the policy authority uses a Taylor-type monetary policy rule. Unlike previous analyses, the model economy is not linearized about a steady state—instead, a global perspective is adopted. Globally, the nonlinear model economy can possess rational expectations equilibria other than the steady state consistent with the inflation target of the monetary authorities. These include a second, low inflation ‘liquidity trap’ steady state, periodic equilibria, and sunspot equilibria. The main results in the paper characterize the conditions under which these alternative equilibria maybe stable under adaptive learning, even when the policy rule obeys the Taylor principle. The stability of multiple equilibria is associated with policy rules which are forecast-based. An important finding is that backward-looking Taylor-type policy rules can guarantee that the unique learnable equilibrium is the steady state associated with the inflation target of the monetary authority.     

Optimal Constrained Interest-Rate Rules

We show that if policymakers compute the optimal unconstrained interest-rate rule within a Taylor-type class, they may be led to rules that generate indeterminacy and/or instability under learning. This problem is compounded by uncertainty about structural parameters since an optimal rule that is determinate and stable under learning for one calibration may be indeterminate or unstable under learning under a different calibration. We advocate a procedure in which policymakers restrict attention to rules constrained to lie in the determinate learnable region for all plausible calibrations, and that minimize the expected loss, computed using structural parameter priors, subject to this constraint.     

Monetary–Fiscal Policy Interactions under Implementable Monetary Policy Rules

This paper examines the implications of forward- and backward-looking monetary policy rules in an environment with monetary–fiscal interactions. We find that the unique stationary rational expectations equilibrium (REE) is always non-Ricardian under simple implementable monetary policy rules.     

Optimal inflation persistence: Ramsey taxation with capital and habits

Ramsey models of fiscal and monetary policy featuring time-separable preferences and a fixed supply of capital predict highly volatile inflation with no serial correlation. In this paper, we show that an otherwise-standard Ramsey model that incorporates capital accumulation and habit persistence predicts highly persistent inflation. The result depends on increases in either the ability to smooth consumption or the preference for doing so. The effect operates through the Fisher relationship: a smoother profile of consumption implies a more persistent real interest rate, which in turn implies persistent optimal inflation. Our work complements a recent strand of the Ramsey literature based on models with nominal rigidities. In these latter models, inflation volatility is lower than in the baseline model but continues to exhibit little persistence. We quantify the effects of habit and capital on inflation persistence and also relate our findings to recent work on optimal fiscal policy with incomplete markets.     

The Interaction between Capital Requirements and Monetary Policy

The interaction between capital requirements and monetary policy is assessed by means of simple rules in a dynamic general equilibrium model featuring a banking sector. In “normal” times, when economic dynamics are driven by supply shocks, an active use of capital requirements generates modest benefits in terms of volatility of the target variables compared to the case in which only the central bank carries out stabilization policies. The lack of cooperation between the two policymakers may result in excessive volatility of the monetary policy rate and capital requirements. The benefits of introducing capital requirements become sizeable when financial shocks, which affect the supply of loans, are important drivers of economic dynamics; the availability of capital requirements as a policy tool yields a significant gain in terms of macroeconomic stabilization, regardless of the type of interaction between monetary and capital requirements policies.     

Optimal Monetary Policy with Labor Market Frictions: The Role of the Wage Channel

This paper introduces right‐to‐manage bargaining into a labor search model with sticky prices instead of standard efficient bargaining and examines the Ramsey‐optimal monetary policy. Without real wage rigidity, even when the steady state is inefficient, price stability is nearly optimal in response to technology or government shocks. Right‐to‐manage bargaining creates the wage channel to inflation, because there is a direct relationship between real wages and real marginal cost. In the presence of the wage channel, price markups consist of only real marginal cost, and real wages and hours per worker are determined such as in the Walrasian labor market.     

Monetary Policy and the Natural Rate of Interest

It is most important for monetary policy to track the natural rate of interest when interest rates take large and sustained swings away from their long‐run equilibrium values. Here, we study two models: a standard New Keynesian model and one in which government bonds provide liquidity. Policy rules that cannot track the natural rate perform poorly in both models, but are especially bad in the second because of sustained movements in the natural rate induced by fiscal shocks. First difference rules, on the other hand, do surprisingly well. When model uncertainty is taken into account, the dominance of the first difference rule is even more pronounced.     

Keynesian Inefficiency and Optimal Policy: A New Monetarist Approach

A simple model of monetary/labor search is constructed to study Keynesian indeterminacy and optimal policy. In the model, economic agents have trouble splitting the surplus from exchange appropriately, and we consider monetary and fiscal policies that correct this Keynesian inefficiency. A Taylor rule neither implies determinacy, nor does it support an efficient outcome. An optimal policy yields an efficient and determinate allocation of resources, but equilibrium policy actions, wages, and prices are indeterminate at the optimum.     

Monetary Policy,Trend Inflation,and Unemployment Volatility

The literature has long agreed that the DMP model (after Diamond 1982, Mortensen 1982, Pissarides 1985) with search and matching frictions in the labor market can deliver large volatilities in labor market quantities, consistent with empirical data, only if there is at least some wage stickiness. I show, however, that the model can deliver nontrivial volatilities without wage stickiness, as long as it has price dispersion and nonzero long‐run inflation rates. I find that by keeping inflation at a positive rate, monetary policy may be accountable for the large standard deviations observed on labor market variables. In addition, the Shimer (2005) puzzle disappears under monetary policy shocks.     

A Further Look at the Propagation of Monetary Policy Shocks in HANK

We provide quantitative guidance on whether and to what extent different elements of Heterogeneous Agent New Keynesian (HANK) models amplify or dampen the response of aggregate consumption to a monetary policy shock. We emphasize four findings. First, the introduction of capital adjustment costs does not affect the aggregate response, but does change the transmission mechanism so that a larger share of indirect effects originates from equity prices rather than from labor income. Second, incorporating estimated unequal incidence functions for aggregate labor income fluctuations leads to either amplification or dampening, depending on the data and estimation methods. Third, distribution rules for monopoly profits that allocate a larger share to liquid assets lead to greater amplification. Fourth, assumptions about the fiscal reaction to a monetary policy shock have a stronger effect on the aggregate consumption response than any of the other three elements.     

Optimal taxation and OECD labor taxes

We derive simple expressions for optimal labor taxes under different assumptions about government bond markets. We use these to examine OECD labor taxes, estimate the excess burden of taxation and assess the ability of optimal tax models to match the data.Optimal labor taxes are driven by: (i) a term reflecting Ramsey considerations which makes labor taxes vary positively with employment and (ii) a martingale component, reflecting the excess burden of tax, which shows persistent responses to shocks to the government's intertemporal budget constraint. Under complete markets (when governments can issue a full set of contingent securities) only the first factor is relevant. We find substantial evidence that incorporating incomplete markets into the optimal taxation model is critical for empirical success. However, we find strongest support for the martingale component and only weak evidence for the Ramsey component.     

The Interaction of Monetary and Macroprudential Policies

I analyze a New Keynesian dynamic stochastic general equilibrium (DSGE) model where the financing of productive investment is affected by a moral hazard problem. I solve for jointly Ramsey‐optimal monetary and macroprudential policies. I find that when a financial friction is present in addition to the standard nominal friction, the optimal policy can replicate the first‐best allocation if the social planner can conduct both monetary and macroprudential policy. Using monetary policy alone is not enough: a policy trade‐off between stabilizing inflation and output gap emerges. When policy follows simple rules, the source of fluctuations is relevant for the choice of the appropriate policy mix.     

Optimal simple and implementable monetary and fiscal rules

Welfare-maximizing monetary- and fiscal-policy rules are studied in a model with sticky prices, money, and distortionary taxation. The Ramsey-optimal policy is used as a point of comparison. The main findings are: the size of the inflation coefficient in the interest-rate rule plays a minor role for welfare. It matters only insofar as it affects the determinacy of equilibrium. Optimal monetary policy features a muted response to output. Interest-rate rules that feature a positive response to output can lead to significant welfare losses. The welfare gains from interest-rate smoothing are negligible. Optimal fiscal policy is passive. The optimal monetary and fiscal rule combination attains virtually the same level of welfare as the Ramsey-optimal policy.     

Fiscal Policy and Occupational Employment Dynamics

We document substantial heterogeneity in occupational employment dynamics in response to government spending shocks in the United States. Employment rises most strongly in service, sales, and office (“pink-collar”) occupations. By contrast, employment in blue-collar occupations is hardly affected by fiscal policy. We provide evidence that occupation-specific changes in labor demand are key for understanding these findings. We develop a business-cycle model that explains the heterogeneous occupational employment dynamics as a consequence of composition effects due to heterogeneous employment changes across industries and occupation-specific within-industry employment shifts due to differences in the short-run substitutability between labor and capital services across occupations.     

Aggregate Stability and Balanced‐Budget Rules

It has been shown that under perfect competition and a Cobb‐Douglas production function, a basic real business cycle model may exhibit indeterminacy and sunspot fluctuations when income tax rates are determined by a balanced‐budget rule (BBR). This paper introduces in an otherwise standard real business cycle model a more general and data‐coherent class of production functions, namely, a constant elasticity of substitution production function. We show that the degree of substitutability between production factors is a key ingredient to understanding the (de)stabilizing properties of a BBR. Then we calibrate the model consistently with the empirical evidence; that is, we set the elasticity of substitution between labor and capital below unity. We show that compared to the Cobb‐Douglas case, the likelihood of indeterminacy under a BBR is greatly reduced in the U.S., the EU, and the UK.     

Price Stability in Economies with Habit Persistence

This paper shows that the divine‐coincidence does not hold in a sticky price model with external habit if a time‐varying tax rate on labor income is not implemented to fully eliminate the time‐varying distortions associated with external habit and monopoly power in goods market. The required labor income tax rate is inversely related to the risk‐free real interest rate and the markup in the goods market, but it is proportional to the degree of external habit. Under this circumstance, the optimal monetary policy commands a countercyclical interest rate, having a perfect negative correlation with tax rate in the sticky price model with external habit. If a time‐invariant tax is the only fiscal instrument, then the degree of external habit entails a gap between the private marginal rate of substitution between consumption and labor and the social marginal rate of substitution, generating an endogenous trade‐off between the stabilization of welfare‐relevant output gap and inflation. Under this circumstance, price stability is not the optimal policy. The monetary policy authority should optimally try to undo the time‐varying distortions associated with external habit and monopoly power in goods market by deviating from price stability.     

What do technology shocks tell us about the New Keynesian paradigm?

Researchers have used unanticipated changes to monetary policy to identify preference and technology parameters of macroeconomic models. This paper uses changes in technology to identify the same set of parameters. Estimates based on technology shocks differ substantially from those based on monetary policy shocks. In the post-World War II United States, a positive technology shock reduces inflation and increases hours worked, significantly and rapidly in both cases. Relative to policy shock identification, technology shock identification implies: (i) long duration durability in preferences instead of short duration habit, (ii) built-in inflation inertia disappears and price flexibility increases. In response to technological improvement, consumption durability increases hours worked because households temporarily increase labor supply to accumulate durables towards a new, higher steady state level. Limited nominal rigidities allow inflation to fall because firms are able to immediately cut prices when households’ labor supply increases. Finally, we consider alternative data constructions and econometric specifications; we find that (i) and/or (ii) hold in nearly every case.