سیاست های پولی و اصطکاک بازار کار : تفسیر مالیاتی

Replicating the flexible price allocation in models with nominal rigidities and labor market frictions that lead to an inefficient matching of unemployed workers with job vacancies, even if feasible, is generally not desirable. We characterize the tax instruments that implement the first best allocation and examine the trade-offs faced by monetary policy if these tax instruments are unavailable. Our tax interpretation helps explain why the welfare cost of inefficient labor market search can be large while the incentive to deviate from price stability is small. Gains from deviating from price stability are larger in economies with more volatile labor flows.

The existence of real distortions in models with nominal rigidities – such as markup shocks in the baseline new Keynesian model – implies that even if replicating the flexible price allocation is feasible, doing so is generally not desirable. In a model with search and matching in the labor market, Ravenna and Walsh (2011) show that random deviations from efficient wage setting play the same role as markup shocks in standard new Keynesian models with Walrasian labor markets. Thus, search frictions endogenously generate a trade-off between using monetary policy to address the inefficiency due to staggered price adjustment and using it to offset deviations from efficient wage setting. Yet in several calibrated versions of the basic search and matching new Keynesian model (e.g., Ravenna and Walsh, 2011, Faia, 2008 and Thomas, 2008), the level of welfare attained by optimal monetary policy appears to deviate very little from the level achieved under a policy of price stability.

To study the policy trade-off generated by distortions arising in models with sticky prices and labor market frictions, we derive the tax policy that corrects the inefficiency wedges in the competitive equilibrium first order conditions. Monetary policy is interpreted as a fiscal instrument that directly affects agents' first order conditions; hence, monetary policy can be described as a way to manipulate markups and correct for the inefficiency wedges in the same way as a tax instrument would. In common with standard new Keynesian models, a subsidy to retail firms is assumed to eliminate the steady-state distortion arising from imperfect competition. In addition to this standard subsidy, three policy instruments are needed to restore the first best. Absent these three instruments, the monetary authority, using only a single instrument, can stabilize the retail price markup to eliminate costly price dispersion and at the same time eliminate the inefficiency wedge in hours setting, or it can move the markup to mimic the cyclical tax that leads to efficient vacancy posting.