As the previous post suggests, I support targeting an NGDP path. I think an NGDP path target is superior in nearly every respect to an inflation target, and so would represent a clear improvement over current practice. 
But, unlike the “market monetarists”, I do not believe that central banks can sustainably track their target, whether NGDP or inflation, given the set of tools currently at their disposal. If those tools are (misguidedly) expanded to permit central banks to lend more freely or purchase a wider range of debt instruments, “success” might prove counterproductive. Although Scott Sumner and Bill Woolsey and Matt Rognlie hate the idea, I think we need to add direct-to-household “helicopter drops” to our menu of instruments. Ultimately, I have a different theory of depressions than the market monetarists do.
Self-fulfilling expectations lie at the heart of the market monetarist theory. A depression occurs when people come to believe that income will be scarce relative to prior expectations and debts. They nervously scale back expenditures and hoard cash, fulfilling their expectations of income scarcity. However, if everybody could suddenly be made to believe that income would be plentiful, everyone would spend freely and fulfill the expectations of plenty. The world is a much more pleasant place under the second set of expectations than the first. And to switch between the two scenarios, all that is required is persuasion. The market-monetarist central bank is nothing more than a great persuader: when “shocks happen”, it persuades us all to maintain our optimism about the path of nominal income. As long as we all keep the faith, our faith will be rewarded. This is not a religion, but a Nash equilibrium.
If the market monetarists’ theory of depressions is correct, then their position is correct. They are famously vague and prickly on the question of what instruments or “concrete steps” central banks will use to achieve their objective. That is because it doesn’t matter one bit, as long as those instruments are persuasive. Whether police wield pistols or tanks or tear gas or nightsticks to keep the peace really doesn’t matter, as long as their choice is sufficiently intimidating that people are deterred from resisting their authority. We only care about the weapon they’ve chosen when deterrence has failed and they are forced to act. Then we are faced with damage from the violence required to sustain their credibility. Even then, if we are certain they will restore order quickly and that incidents of disorder will be rare, we might not worry so much over means. But if conditions are such that lawlessness will not be deterred, there will be no general peace but frequent mêlées on the streets, then it matters very much how the police fight their battles. We start to ask whether the medicine is better than the side effects, whether police tactics are well tailored to improve the underlying conditions and restore a durable peace.
I have a Minsky/Mankiw theory of depressions. The economy is divided into two kinds of people, spenders and savers. Perhaps some people lack impulse control and have bad character, while others are patient and provident. Perhaps structural inequality renders some people hungry but cash-constrained, while others have income in excess of satiable consumption. Let’s put those questions aside and just posit two different and reasonably stable groups of people. Variation in aggregate expenditure is due mostly to changes in the behavior of the spenders. Savers spend at a relatively constant rate and save the rest. Spenders spend whatever they can earn or borrow, which varies with the level of wages, the cost of servicing debt they’ve accrued in the past, and the availability of new credit.
In this world, a central bank that targets something — NGDP, inflation, whatever — doesn’t regulate behavior via expectations. Instead, the central bank regulates access to credit and wages. When the economy is “overheating”, the central bank raises interest rates to increase debt servicing costs, tightens credit standards to diminish new borrowing, and if absolutely necessary squeezes so hard that a recession reduces spenders’ wages via unemployment. When the economy is below potential, the central bank reduces interest rates and relaxes credit standards, encouraging spenders to borrow and leaving them with higher wages net of interest payments.
This is a pretty good gig, it works pretty well, especially when the marginal dollar of expenditure is borrowed and easily regulated by the central bank. But if there are lower bounds on interest rates and credit standards, the scheme is not indefinitely sustainable. Even when spenders hold consistent, reasonably optimistic expectations about the economy, it becomes continually more difficult to persuade them to maintain their level of spending. The cost of debt service grows as their indebtedness grows, reducing their ability to spend. New borrowing becomes more difficult as wages are dwarfed by liabilities. Individuals become more nervous that some blip in their complicated lives will leave them unable to meet their obligations. In order to hold expenditure constant, interest rates must fall, credit standards must loosen, the value of spenders’ one consumption good that survives as pledgeable collateral — their homes — must be made to rise. Stabilizing expenditure requires continual easing. Any sort of lower bound provokes a “Minsky moment”, as expenditures that can no longer be sustained unexpectedly contract, rendering maxed-out spenders unable to service their debts.
All of this is just a theory, but I think it fits the facts better than a theory that takes stable demand and depression as arbitrary “sunspot” equilibria, selected by expectations. If the demand-stable “great moderation” had been an equilibrium, one might expect parameters like interest rates and aggregate indebtedness to be stable or to mean-revert around their long-term values. They were not. Interest rates were in secular decline throughout the period, and the indebtedness of some households to others was consistently rising as a fraction of GDP. Credit standards declined.
If my theory is right, absent significant structural change, attempting to restore demand merely by shocking expectations would be like trying to defibrillate a corpse. Yes, NGDP expectations absolutely did collapse over the course of 2008, but that was not due to a transient shock but a secular change which made the prior stabilization regime untenable. The housing collapse and credit crisis made it impossible to sustain expenditure by loosening credit standards. That left interest rates as the only tool by which to encourage spenders, but the zero nominal bound and rising credit spreads rendered that lever insufficient. Since 2008, whenever expectations have begun to perk up — and they have, several times — yet another “shock” has come along and returned us to pessimism (“OMG, Europe!”). Eventually you have to wonder whether there isn’t something more than arbitrary about these negative expectations.
The market monetarists might retort that a sufficiently determined central bank, if given license to lend and purchase assets as it sees fit, can always meet a nominal spending target, and therefore can always set expectations of nominal demand. That may be true. But in the context of an economy structurally resistant to increasing expenditure, expectations of stable nominal income become equivalent to expectations of continual central bank expansion. NGDP expectations can be maintained, if and only if the central bank demonstrates its willingness to continually intervene.
If intervention will be frequent and chronic, precisely what instruments the central bank intends to use becomes a matter of great public concern, rather than a technocratic detail best left to professionals. Central banks may significantly shape patterns of consumption and investment by choosing to whom they are willing to lend and on what terms. They may pick winners and losers, not for a brief
Paul Volcker Chuck Norris moment but for the indefinite future.
So, I am all for targeting an NGDP path. I think it’s a great idea, and have more nice things to say about it. I hope the market monetarists are right, that merely by announcing an NGDP target and showing resolve in a one-time wrestling match with skeptics, central banks can restore a high-demand equilibrium. But if we adopt an NGDP target and are serious about it, there is significant risk that we will be committing to chronic intervention. The market monetarists owe us a more serious conversation than they’ve offered so far about how monetary policy would be conducted if resetting expectations turns out not to be enough. Would the interventions they propose be fair, if pursued cumulatively over many years? Would they be wise? Would they help resolve the structural problems that have rendered it so difficult to sustain demand, or would they exacerbate those problems?
 Yes, the US Federal Reserve has its murky triple mandate. But in practice tracking a tacit inflation target seems to dominate. Other central banks are at least explicit in their poor choice of a target.
- 29-Oct-2011, 7:10 p.m. EDT: Changed “a more durable peace” to “a durable peace”. “there is a significant risk” to “there is significant risk”.