This paper compares different implementations of monetary policy in a new-Keynesian setting. We can show that a shift from Ramsey optimal policy under short-term commitment (based on a negative feedback mechanism) to a Taylor rule (based on a positive feedback mechanism) corresponds to a Hopf bifurcation with opposite policy advice and a change of the dynamic properties. This bifurcation occurs because of the ad hoc assumption that interest rate is a forward-looking variable when policy targets (inflation and output gap) are forward-looking variables in the new-Keynesian theory.

As originally published the first keyword in this list was misspelled. The publisher regrets the error and displays the keywords correctly here:

The perception that inflation targeting (IT) runs a high risk of indeterminacy when a significant share of households are too poor to save is an artifact of the closed economy. In the open economy, the Taylor principle is generally valid for both contemporaneous and forward-looking IT. Active policy in contemporaneous IT guarantees determinacy, eccentric cases aside. In forward-looking IT, the scope for active policy is constrained by an upper bound on the Taylor coefficient. The upper bound is insensitive, however, to the share of poor, nonsaving households. Moreover, it can be increased substantially–to a level that does not bind–through reserve sales/purchases that limit exchange rate volatility.

This paper examines the local determinacy implications of using consumption taxes and income taxes to finance a balanced budget fiscal policy for a variety of popular monetary policy rules. It is shown using a New Keynesian framework that the severity of the indeterminacy problem that arises under each tax system depends not only on the specification of the interest-rate feedback rule, but also on the magnitude of the steady state tax rate, the steady state government debt–output ratio, and the degree of price stickiness. Significant differences in the determinacy criteria across the two tax systems are found to exist. The robustness of the results is assessed by extending the baseline model to include capital accumulation and the taxation of bond interest income. From a policy perspective, our results suggest that future shifts toward indirect taxation could have nontrivial implications for the setting of monetary policy under balanced budget rules, in particular the ability of the Taylor principle to achieve determinacy.

Early research on the Taylor rule typically divided the data exogenously into pre-Volcker and Volcker–Greenspan subsamples. We contribute to the recent trend of endogenizing changes in monetary policy by estimating a real-time forward-looking Taylor rule with endogenous Markov switching coefficients and variance. The response of the interest rate to inflation is regime-dependent, with the pre- and post-Volcker samples containing monetary regimes where the Fed did and did not follow the Taylor principle. Although the Fed consistently adhered to the Taylor principle before 1973 and after 1984, it followed the Taylor principle from 1975 to 1979 and did not follow the Taylor principle from 1980 to 1984. We also find that the Fed only responded to real economic activity during the states in which the Taylor principle held. Our results are consistent with the idea that exogenously dividing postwar monetary policy into pre- and post-Volcker samples is misleading. The greatest qualitative difference between our results and recent research employing time-varying parameters is that we find that the Fed did not adhere to the Taylor principle during most of Paul Volcker's tenure, a finding that accords with the historical record of monetary policy.

We introduce skill decay during unemployment into a New Keynesian model with hiring frictions and real-wage rigidity. Plausible values of quarterly skill decay and real-wage rigidity turn the long-run marginal cost–unemployment relationship positive in a “European” labor market with little hiring but not in a fluid “American” one. If the marginal cost–unemployment relationship is positive, determinacy requires a passive response to inflation in the central bank's interest feedback rule if the rule features only inflation. Targeting steady-state output or unemployment helps to restore determinacy.

This paper studies the determinacy of equilibrium in a new Keynesian model with deep habits under different interest rate rules. The main finding is that an interest rate rule satisfying the Taylor principle is no longer a sufficient condition to guarantee determinacy. Including interest rate smoothing and a response to output deviations from steady state significantly enlarges the regions of determinacy. However, under all the simple interest rate rules considered, determinacy is not guaranteed for a very high degree of deep habits. Deep habits give rise to countercyclical markups, which is in line with empirical evidence and makes them an appealing feature in the study of demand shocks. The countercyclicality of markups also leads to multiple equilibria because of self-fulfilling expectations for a high degree of deep habit formation.

Bullard and Mitra [Journal of Monetary Economics 49 (2002), 1105–1130] find that, in a New Keynesian economy without capital and under four variants of the Taylor rule, the Taylor principle is sufficient to guarantee both determinacy and E-stability of equilibrium in most cases. Xiao [Macroeconomic Dynamics 12 (2008), 22–49] claims that with capital and mild increasing returns the Taylor principle cannot guarantee either determinacy or E-stability with any of the four rules. In this paper we show that in the Calvo-type sticky price models a second-order condition for profit maximization must be satisfied in firms' pricing decision problem, and we point out that the examples given in Xiao's paper to support his conclusion violate this condition. After imposing this condition, we find that increasing returns have little effect on determinacy and E-stability under two of the policy rules but significant effects under the other two. These results are obtained in models both with and without capital.

We introduce increasing returns to scale into an otherwise standard New Keynesian model with capital, and study the determinacy and E-stability of equilibrium under Taylor-type interest rate rules. With very mild increasing returns supported by empirical research, the conventional wisdom regarding the design of interest rate rules can be overturned. In particular, the “Taylor principle” no longer guarantees either determinacy or E-stability of the rational expectations equilibrium.