We show that a sticky price model featuring firms' heterogeneity in terms of productivity and strategic complementarities in price setting delivers a strictly positive optimal inflation in steady state, differently from standard New Keynesian models. Due to strategic complementarities, more productive firms have higher markups in steady state. This leads to a misallocation distortion, as more productive firms produce too little compared to the social optimum. An increase of steady state inflation curbs the markups, especially those of the more productive firms, hence attenuating the inefficient dispersion of markups. At low levels of inflation, the gains from the reduction in misallocation outweigh the cost of inflation. Heterogeneity in productivity and strategic complementarities in price setting, the key ingredients of our model, imply that also firms' response to shocks is heterogenous: less productive firms transmit cost shocks to prices much more than more productive ones. To provide empirical support to our key mechanism we resort to a quasi-natural experiment occurred in Italy in late 2014, when a cut to social security contributions for all new open-ended contracts was announced. Consistently with our theory, we show that the pass-through of this shock to labour costs was much stronger for less productive firms.

The classic introduction to the New Keynesian economic model This revised second edition of Monetary Policy, Inflation, and the Business Cycle provides a rigorous graduate-level introduction to the New Keynesian framework and its applications to monetary policy. The New Keynesian framework is the workhorse for the analysis of monetary policy and its implications for inflation, economic fluctuations, and welfare. A backbone of the new generation of medium-scale models under development at major central banks and international policy institutions, the framework provides the theoretical underpinnings for the price stability–oriented strategies adopted by most central banks in the industrialized world. Using a canonical version of the New Keynesian model as a reference, Jordi Galí explores various issues pertaining to monetary policy's design, including optimal monetary policy and the desirability of simple policy rules. He analyzes several extensions of the baseline model, allowing for cost-push shocks, nominal wage rigidities, and open economy factors. In each case, the effects on monetary policy are addressed, with emphasis on the desirability of inflation-targeting policies. New material includes the zero lower bound on nominal interest rates and an analysis of unemployment’s significance for monetary policy. The most up-to-date introduction to the New Keynesian framework available A single benchmark model used throughout New materials and exercises included An ideal resource for graduate students, researchers, and market analysts

This paper analyzes the use of unconventional policy instruments in New Keynesian setups in which the ‘divine coincidence’ breaks down. The paper discusses the role of a second instrument and its coordination with conventional interest rate policy, and presents theoretical results on equilibrium determinacy, the inflation bias, the stabilization bias, and the optimal central banker’s preferences when both instruments are available. We show that the use of an unconventional instrument can help reduce the zone of equilibrium indeterminacy and the volatility of the economy. However, in some circumstances, committing not to use the second instrument may be welfare improving (a result akin to Rogoff (1985a) example of counterproductive coordination). We further show that the optimal central banker should be both aggressive against inflation, and interventionist in using the unconventional policy instrument. As long as price setting depends on expectations about the future, there are gains from establishing credibility by using any instrument that affects these expectations.

We study the effects of positive steady-state inflation in New Keynesian models subject to the zero bound on interest rates. We derive the utility-based welfare loss function taking into account the effects of positive steady-state inflation and show that steady-state inflation affects welfare through three distinct channels: steady-state effects, the magnitude of the coefficients in the utility-function approximation, and the dynamics of the model. We solve for the optimal level of inflation in the model and find that, for plausible calibrations, the optimal inflation rate is low, less than two percent, even after considering a variety of extensions, including price indexation, endogenous price stickiness, capital formation, model-uncertainty, and downward nominal wage rigidities. In our models, price level targeting delivers large welfare gains and a very low optimal inflation rate consistent with price stability.

In recent years, New Keynesian dynamic stochastic general equilibrium (NK DSGE) models have become increasingly popular in the academic literature and in policy analysis. However, the success of these models in reproducing the dynamic behavior of an economy following structural shocks is still disputed. This paper attempts to shed light on this issue. We use a VAR with sign restrictions that are robust to model and parameter uncertainty to estimate the effects of monetary policy, preference, government spending, investment, price markup, technology, and labor supply shocks on macroeconomic variables in the United States and the euro area. In contrast to the NK DSGE models, the empirical results indicate that technology shocks have a positive effect on hours worked, and investment and preference shocks have a positive impact on consumption and investment, respectively. While the former is in line with the predictions of Real Business Cycle models, the latter indicates the relevance of accelerator effects, as described by earlier Keynesian models. We also show that NK DSGE models might overemphasize the contribution of cost-push shocks to business cycle fluctuations while, at the same time, underestimating the importance of other shocks such as changes to technology and investment adjustment costs.

Abstract: In recent years New Keynesian models have become the dominant framework in macroeconomics for the study of monetary policy and business cycle fluctuations. In this class of models it is typically assumed that labor is purchased in a rental spot market. The effect of modeling labor markets in a more realistic way has been an understudied topic in the literature. This dissertation explores how the introduction of frictions in labor markets helps solve some of the puzzles faced by New Keynesian models. In the first chapter, I extend the standard New Keynesian model by incorporating labor adjustment costs and overtime work. I show that labor frictions help reconcile the frequent price changes found in the microdata with the degree of sluggishness in inflation at the macro level. The introduction of labor frictions affects the dynamic behavior of economic variables (particularly employment and inflation) and implies that firm's marginal costs should be measured in overtime costs. Marginal costs measured in overtime hours are procyclical and are predicted by inflation as suggested by theory. In the second chapter, I make use of a Bayesian likelihood approach to estimate a DSGE of the US economy using macro-economic time series. The estimated model is an extended version of the New Keynesian model with overtime labor developed in the first chapter. I show that the model does not need a high degree of price stickiness at the firm level in order to account for inflation dynamics and that it yields positive employment responses to productivity shocks. In the third chapter, the New Keynesian Phillips Curve is estimated with a marginal cost measure corrected for labor adjustment costs across different countries. I find that the labor share is a statistically significant determinant of inflation in regressions using the present value of the labor share but not in GMM regressions (in most cases). I then relate the estimates on the labor adjustment costs coefficients to measures of employment protection legislation.