MPCs, MPEs, and Multipliers: A Trilemma for New Keynesian Models Adrien Auclert* Bence Bardóczy† Matthew Rognlie‡ March 2021 Abstract We show that New Keynesian models with frictionless labor supply face a challenge: given standard parameters, they cannot simultaneously match plausible estimates of marginal propen- sities to consume (MPCs), marginal propensities to earn (MPEs), and fiscal multipliers. A HANK model with sticky wages provides a solution to this trilemma. Introduction In recent decades, macroeconomics has experienced a micro-moment revolution. As the field has recognized the importance of heterogeneity for macroeconomic outcomes, it has increasingly used estimates from disaggregated data to discipline its models. One moment that epitomizes this revolution is the marginal propensity to consume (MPC): the amount by which consumption increases in response to a one-time transitory increase in income. Recent research has established that MPCs are extremely important for the macroeconomic effects of shocks and policy, both in partial equilibrium (e.g. Kaplan and Violante 2014, Auclert 2019, Berger, Guerrieri, Lorenzoni and Vavra 2018) and in general equilibrium (e.g. Kaplan, Moll and Violante 2018, Auclert, Rognlie and Straub 2018). Moreover, there exists a widespread consensus on the average level of MPCs in the data. We summarize this consensus as: Fact 1. Average MPCs are high in the data, around 0.25 quarterly and 0.5 annually. *Stanford University, CEPR and NBER. Email:
[email protected]. †Northwestern University. Email:
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[email protected]. An earlier version of this paper circulated under the title “A Note on Multipliers in NK Models with GHH Preferences”.