Pascal Michaillat

A theory of countercyclical government multiplier

I develop a New Keynesian model in which a type of government multiplier doubles when unemployment rises from 5 percent to 8 percent. This multiplier indicates the additional number of workers employed when one worker is hired in the public sector. Graphically, in equilibrium, an upward-sloping quasi-labor supply intersects a downward-sloping labor demand in a (employment, labor market tightness) plane. Increasing public employment stimulates labor demand, which increases tightness and therefore crowds out private employment. Critically, the quasi-labor supply is convex. Hence, when labor demand is depressed and unemployment is high, the increase in tightness and resulting crowding-out are small.

A Macroeconomic Theory of Optimal Unemployment Insurance

We develop a theory of optimal unemployment insurance (UI) that accounts for workers’ job-search behavior and firms’ hiring behavior. The optimal replacement rate of UI is the conventional Baily [1978]-Chetty [2006a] rate, which solves the trade-off between insurance and job-search incentives, plus a correction term, which is positive when UI brings the labor market tightness closer to efficiency. For instance, when tightness is inefficiently low, optimal UI is more generous than the Baily-Chetty rate if UI raises tightness and less generous if UI lowers tightness. We propose empirical criteria to determine whether tightness is inefficiently high or low and whether UI raises or lowers tightness. The theory has implications for the cyclicality of optimal UI.

An Economical Business-Cycle Model

In recent decades, advanced economies have experienced low and stable inflation and long periods of liquidity trap. We construct an alternative business-cycle model capturing these two features by adding two assumptions to a money-in-the-utility-function model: the labor market is subject to matching frictions, and real wealth enters the utility function. These assumptions modify the two core equations of the standard New Keynesian model. With matching frictions, we can analyze equilibria in which inflation is fixed and not determined by a forward-looking Phillips curve. With wealth in the utility, the Euler equation is modified and we can obtain steady-state equilibria with a liquidity trap, positive inflation, and labor market slack. The model is simple enough to inspect the mechanisms behind cyclical fluctuations and to study the effects of conventional and unconventional monetary and fiscal policies. As a byproduct, the model provides microfoundations for the classical IS-LM model. Finally, we show how directed search can be combined with costly price adjustments to generate a forward-looking Phillips curve and recover some insights from the New Keynesian model.

The Optimal Use of Government Purchases for Macroeconomic Stabilization

This paper extends Samuelson’s theory of optimal government purchases by considering the contribution of government purchases to macroeconomic stabilization. We consider a matching model in which unemployment can be too high or too low. We derive a sufficient-statistics formula for optimal government purchases. Our formula is the Samuelson formula plus a correction term proportional to the government-purchases multiplier and the gap between actual and efficient unemployment rate. Optimal government purchases are above the Samuelson level when the correction term is positive—for instance, when the multiplier is positive and unemployment is inefficiently high. Our formula indicates that US government purchases, which are mildly countercyclical, are optimal under a small multiplier of 0.03. If the multiplier is larger, US government purchases are not countercyclical enough. Our formula implies significant increases in government purchases during slumps. For instance, with a multiplier of 0.5 and other statistics calibrated to the US economy, when the unemployment rate rises from the US average of 5.9% to 9%, the optimal government purchases-output ratio increases from 16.6% to 19.8%. However, the optimal ratio increases less for multipliers above 0.5 because with higher multipliers, the unemployment gap can be filled with fewer government purchases. For instance, with a multiplier of 2, the optimal ratio only increases from 16.6% to 17.6%.

Preferences for Fair Prices, Cursed Inferences, and the Nonneutrality of Money

This paper explains the nonneutrality of money from two assumptions: (1) consumers dislike paying prices that exceed some fair markup on firms’ marginal costs; and (2) consumers under infer marginal costs from available information. After an increase in money supply, consumers underappreciate the increase in nominal marginal costs and hence partially misattribute higher prices to higher markups; they perceive transactions as less fair, which increases the price elasticity of their demand for goods; firms respond by reducing markups; in equilibrium, output increases. By raising perceived markups, increased money supply inflicts a psychological cost on consumers that can offset the benefit of increased output.