Fiscal Multipliers over the Business Cycle

This paper illustrates why fiscal policy becomes more effective as unemployment rises in recessions. The theory is based on the equilibrium unemployment model of Michaillat (forthcoming), in which jobs are rationed in recessions. Fiscal policy takes the form of government spending on public-sector jobs. Recessions are periods of acute job shortage without much competition for workers among recruiting firms; hiring in the public sector does not crowd out hiring in the private sector much; therefore fiscal policy reduces unemployment effectively. Formally the fiscal multiplier—the reduction in unemployment rate achieved by spending one dollar on public-sector jobs—is countercyclical. An implication is that available estimates of the fiscal multiplier, which measure the average effect of fiscal policy over the business cycle, do not apply in recessions because the multiplier is much higher in recessions than on average.Fiscal multiplier, unemployment, business cycle, job rationing, matching frictions

Incentive-Compatible Critical Values

Statistical hypothesis tests are a cornerstone of scientific research. The tests are informative when their size is properly controlled, so the frequency of rejecting true null hypotheses (type I error) stays below a prespecified nominal level. Publication bias exaggerates test sizes, however. Since scientists can typically only publish results that reject the null hypothesis, they have the incentive to continue conducting studies until attaining rejection. Such $p$-hacking takes many forms: from collecting additional data to examining multiple regression specifications, all in the search of statistical significance. The process inflates test sizes above their nominal levels because the critical values used to determine rejection assume that test statistics are constructed from a single study---abstracting from $p$-hacking. This paper addresses the problem by constructing critical values that are compatible with scientists' behavior given their incentives. We assume that researchers conduct studies until finding a test statistic that exceeds the critical value, or until the benefit from conducting an extra study falls below the cost. We then solve for the incentive-compatible critical value (ICCV). When the ICCV is used to determine rejection, readers can be confident that size is controlled at the desired significance level, and that the researcher's response to the incentives delineated by the critical value is accounted for. Since they allow researchers to search for significance among multiple studies, ICCVs are larger than classical critical values. Yet, for a broad range of researcher behaviors and beliefs, ICCVs lie in a fairly narrow range

A Model of Unemployment with Matching Frictions and Job Rationing: Dissertation Summary

Large fluctuations in unemployment frequently recur across the United States and Europe, most recently in 2009, and remain a major concern for policymakers. Many different macroeconomic theories of unemployment have been offered. These theories deliver conflicting results about the welfare cost of unemployment and the impact of various labor market policies, which makes it difficult to develop policy recommendations. In fact, there seems to be no consensus on how much governments should spend on unemployment-reducing policies, and which specific policies they should implement. Therefore, it is critical to identify the main sources of unemployment over the business cycle in order to develop effective unemployment-reducing policies

Optimal Unemployment Insurance over the Business Cycle

This paper examines how optimal unemployment insurance (UI) responds to the state of the labor market. The theoretical framework is a matching model of the labor market with general production function, wage-setting mechanism, matching function, and preferences. We show that optimal UI is the sum of a conventional Baily-Chetty term, which captures the trade-off between insurance and job-search incentives, and a correction term, which is positive if UI brings labor market tightness closer to its efficient level. The state of the labor market determines whether tightness is inefficiently low or inefficiently high. The response of optimal UI to the state of the labor market therefore depends on the effect of UI on tightness. For instance, if the labor market is slack and tightness is inefficiently low, optimal UI is more generous than the Baily-Chetty level if UI raises tightness and less generous if UI lowers tightness. Depending on the production function and the wage-setting mechanism, UI could raise tightness, for example by alleviating the rat race for jobs, or lower tightness, for example by increasing wages through bargaining. To determine whether UI raises or lowers tightness in practice, we develop an empirical criterion. The criterion involves a comparison of the microelasticity and the macroelasticity of unemployment with respect to UI.

Optimal Unemployment Insurance Over the Business Cycle

This paper characterizes optimal unemployment insurance (UI) over the business cycle using a model of equilibrium unemployment in which jobs are rationed in recession. It offers a simple optimal UI formula that can be applied to a broad class of equilibrium unemployment models. In addition to the usual statistics (risk aversion and micro-elasticity of unemployment with respect to UI), a macro-elasticity appears in the formula to capture the macroeconomic impact of UI on unemployment. In a model with job rationing, the formula implies that optimal UI is countercyclical. This result arises because in recession, jobs are lacking irrespective of job search. Therefore (1) a higher aggregate search effort cannot reduce aggregate unemployment much; and (2) individual search effort creates a negative externality by reducing other jobseekers' probability of finding a job as in a rat race. Hence the social benefits of job search are low. In a calibrated model, optimal UI increases significantly in recession. This quantitative result holds whether the government adjusts the level or duration of benefits; whether it balances its budget each period or uses deficit spending.Unemployment insurance, business cycle, job rationing, matching frictions

Moen Meets Rotemberg: An Earthly Model of the Divine Coincidence

This paper proposes a model of the divine coincidence, explaining its recent appearance in US data. The divine coincidence matters because it helps explain the behavior of inflation after the pandemic, and it guarantees that the full-employment and price-stability mandates of the Federal Reserve coincide. In the model, a Phillips curve relating unemployment to inflation arises from Moen's (1997) directed search. The Phillips curve is nonvertical thanks to Rotemberg's (1982) price-adjustment costs. The model's Phillips curve guarantees that the rate of inflation is on target whenever the rate of unemployment is efficient, generating the divine coincidence. If we assume that wage decreases -- which reduce workers' morale -- are more costly to producers than price increases -- which upset customers -- the Phillips curve also displays a kink at the point of divine coincidence

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 sufficientstatistics 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

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