New Keynesians Don't Believe Their Models

Here's the thing about about saltwater, New Keynesian economists: They don't believe their own theory.

Via John Cochrane, here is a great example. In the NBER Macroeconomics Annual a couple years ago, Gauti Eggertson laid out the canonical New Keynesian case for the effectiveness of fiscal policy when interest rates are at the Zero Lower Bound. In the model Eggertson describes there -- the model that is supposed to provide the intellectual underpinnings for fiscal stimulus -- the multiplier on government spending at the ZLB is indeed much larger than in normal conditions, 2.3 rather than 0.48. But the same model says that at the ZLB, cuts in taxes on labor are contractionary, with a multiplier of -1. Every dollar of "stimulus" from the Making Work Pay tax credit, in other words, actually reduced GDP by a dollar. Or as Eggertson puts it, "Cutting taxes on labor ... is contractionary under the circumstances the United States is experiencing today. "

Now, obviously there are reasons why one might believe this. For instance, maybe lower payroll taxes just allow employers to reduce wages by the same amount, and then in response to their lower costs they reduce prices, which is deflationary. There's nothing wrong with that story in principle. No, the point isn't that the New Keynesian claim that payroll tax cuts reduce demand is wrong -- though I think that it is. The point is that nobody actually believes it.

In the debates over the stimulus bill back at the beginning of 2009, everyone agreed that payroll tax cuts were stimulus just as much as spending increases. The CBO certainly did. There were plenty of "New Keynesian" economists involved in that debate, and while they may have said that tax cuts would boost demand less than direct government spending, I'm pretty sure that not one of them said that payroll tax cuts would actually reduce demand. And when the payroll tax cuts were allowed to expire at the end of 2012, did anyone make the case that this was actually expansionary? Of course not. The conventional wisdom was that the payroll tax cuts had a large, positive effect on demand, with a multiplier around positive 1. Regardless of good New Keynesian theory.

As a matter of fact, even Eggertson doesn't seem to believe that raising taxes on labor will boost demand, whether or not it's what the math says. The "natural result" of his model, he admits, is that any increase in government spending should be financed by higher taxes. But:

There may, however, be important reasons outside the model that suggest that an increase in labor and capital taxes may be unwise and/or impractical. For these reasons I am not ready to suggest, based on this analysis alone, that raising capital and labor taxes is a good idea at zero interest rates. Indeed, my conjecture is that a reasonable case can be made for a temporary budget deficit to finance a stimulus plan... 

Well, yeah. I think most of us can agree that raising payroll taxes in a recession is probably not the best idea. But at this point, what are we even doing here? If you're going to defer to arguments "outside the model" whenever the model says something inconvenient or surprising, why are you even doing it?


EDIT: I put this post up a few days ago, then took it down because it seemed a little thin and I thought I would add another example or two of the same kind of thing. But I'm feeling now that more criticism of mainstream economics is not a good use of my time. If that's what you want, you should check out this great post by Noah Smith. Noah is so effective here for the same reason that he's sometimes so irritatingly wrong -- he's writing from inside the mainstream. The truth is, to properly criticize these models, you have to have a deep knowledge of them, which he has and I do not.

Arjun and I have a piece in an upcoming Economics and Politics Weekly on how liberal, "saltwater" economists share the blame for creating an intellectual environment favorable to austerian arguments, however much they oppose them in particular cases. I feel pretty good about it -- will link here when it comes out -- I think for me, that's enough criticism of modern macro. In general, the problem with radical economists is they spend too much time on negative criticism of the economics profession, and not enough making a positive case for an alternative. This criticism applies to me too. My comparative advantage in econblogging is presenting interesting Keynesian and Marxist work.

One thing one learns working at a place like Working Families, the hard thing is not convincing people that shit is fucked up and bullshit, the hard thing is convincing them there's anything they can do about it.  Same deal here: The real challenge isn't showing the other guys are wrong, it's showing that we have something better.

That Safe Asset Shortage, Continued

Regular readers of the blog will know that we have been having a contradiction with Brad DeLong and the rest of the monetarist mainstream of modern macroeconomics.

They think that demand constraints imply, by definition, an excess demand for money or "safe assets." Unemployment implies disequilibrium, for them; if everyone can achieve their desired transactions at the prevailing prices, then society's productive capacity will always be fully utilized. Whereas I think that the interdependence of income and expenditure means that all markets can clear at a range of different levels of output and employment.

What does this mean in practice? I am pretty sure that no one thinks the desire to accumulate safe assets  directly reduces demand for current goods from households and nonfinancial businesses. If a safe asset shortage is restricting demand for real goods and services, it must be via an unwillingness of banks to hold the liabilities of nonfinancial units. Somebody has to be credit constrained.

So then: What spending is more credit constrained now, than before the crisis?

It's natural to say, business investment. But in fact, nonresidential investment is recovering nicely. And as I pointed out last week, by any obvious measure credit conditions for business are exceptionally favorable. Risky business debt is trading at historically low yields, while the volume of new issues of high-risk corporate debt is more than twice what it was on the eve of the crisis. There's some evidence that credit constraints were important for businesses in the immediate post-Lehmann period, if not more recently; but even for the acute crisis period it's hard to explain the majority of the decline in business investment that way. And today, it certainly looks like the supply of business credit is higher, not lower, than before 2008.

Similarly, if a lack of safe assets has reduced intermediaries' willingness to hold household liabilities, it's hard to see it in the data. We know that interest rates are low. We know that most household deleveraging has taken place via default, as opposed to reduced borrowing. We know the applications for mortgages and new credit cards have continued to be accepted at the same rate as before the crisis. And this week's new Household Credit and Debt Report confirms that people are coming no closer than before the crisis, to exhausting their credit-card credit. Here's a graph I just made of credit card balances and limits, from the report:

Ratio of total credit card balances to total limits (blue bars) on left scale; indexes of actual and trend consumption (orange lines) on right scale. Source: New York Fed.

The blue bars show total credit card debt outstanding, divided by total credit card limits. As you can see, borrowers did significantly draw down their credit in the immediate crisis period, with balances rising from about 23% to about 28% of total credit available. This is just as one would expect in a situation where more people were pushing up against liquidity constraints. But for the past year and a half, the ratio of credit card balances to limits has been no higher than before the crisis. Yet, as the orange lines show, consumption hasn't returned to the pre-crisis trend; if anything, it continues to fall further behind. So it looks like a large number of household were pressing against their credit limit during the recession itself (as during the previous one), but not since 2011. One more reason to think that, while the financial crisis may have helped trigger the downturn, household consumption today is not being held back a lack of available credit, or a safe asset shortage.

If it's credit constraints holding back real expenditure, who or what exactly is constrained?

Tell Me About that "Safe Asset Shortage" Again

From today's FT:

US Junk Debt Yield Hits Historic Low

The average yield on US junk-rated debt fell below 5 per cent for the first time on Monday, setting yet another milestone in a multiyear rally and illustrating the massive demand for fixed income returns as central banks suppress interest rates. 

Junk bonds and equities often move in tandem, and with the S&P 500 rising above 1,600 points for the first time and sitting on a double digit gain this year, speculative rated corporate bonds are also on a tear. ... With corporate default rates below historical averages, investors are willing to overlook the weaker credit quality in exchange for higher returns on the securities, analysts said. ... The demand for yield has become the major driver of investor behaviour this year, as they downplay high valuations for junk bonds and dividend paying stocks. 

“Maybe the hurdles of 6 per cent and now 5 per cent on high-yield bonds are less relevant given the insatiable demand for income,” said Jim Sarni, managing principal at Payden & Rygel. “People need income and they are less concerned about valuations.”

In other words, the demand for risky assets is exceptionally high, and this has driven up their price. Or to put it the other way, if you are a high-risk corporate borrower, now is a very good time to be looking for a loan.

Here's the same thing in a figure. Instead of their absolute yield, this shows the spread of junk bonds over AAA:

Difference between CCC- and AAA bond yields

See how high it is now, over on the far right? Yeah, me neither. But if the premium for safe assets is currently quite low, how can you say that it is a shortage of safe assets that is holding back the recovery? If financial markets are willing to lend money to risky borrowers on exceptionally generous terms, how can you say the problem is a shortage of risk-bearing capacity?

Now, the shortage-of-safe-assets story does fit the acute financial crisis period. There was a period in late 2008 and early 2009 when banks were very wary of holding risky assets, and this may have had real effects. (I say "may" because some large part of the apparent fall in the supply of credit in the crisis was limited to banks' unwillingness to lend to each other.) But by the end of 2009, the disruptions in the financial markets were over, and by all the obvious measures credit was as available as before the crisis. The difference is that now households and firms wished to borrow less. So, yes, there was excess demand for safe assets in the crisis itself; but since then, it seems to me, we are in a situation where all markets clear, just at a lower level of activity.

This is a perfect illustration of the importance of the difference between the intertemporal optimization vision of modern macro, and the income-expenditure vision of older Keynesian macro. In modern macro, it is necessarily true that a shortfall of demand for currently produced goods and services is equivalent to an excess demand for money or some other asset that the private sector can't produce. Or as DeLong puts it:

If you relieve the excess demand for financial assets, you also cure the excess supply of goods and services (the shortfall of aggregate demand) and the excess supply of labor (mass unemployment).

Because what else can people spend their (given, lifetime) income on, except currently produced stuff or assets? If they want less of one, that must mean they want more of the other.

In the Keynesian vision, by contrast, there's no fixed budget -- no endowment -- to be allocated. People don't know their lifetime income; indeed, there is no true expected value of future income out there for them to know. So households and businesses adjust current spending based on current income. Which means that all markets can clear at a various different levels of aggregate activity. Or in other words, people can rationally believe they are on their budget constraint at different levels of expenditure, so there is no reason that a decline in desired expenditure in one direction (currently produced stuff) has to be accompanied by an increase in some other direction (safe assets or money).

(This is one reason why fundamental uncertainty is important to the Keynesian system.)

For income-expenditure Keynesians, it may well be true that the financial meltdown triggered the recession. But that doesn't mean that an ongoing depression implies an ongoing credit crisis. Once underway, a low level of activity is self-reinforcing, even if financial markets return to a pristine state and asset markets all clear perfectly. Modern macro, on the other hand, does need a continued failure in financial markets to explain output continuing to fall short of potential. So they imagine a "safe asset shortage" even when the markets are shouting "safe asset glut."


EDIT: I made this same case, more convincingly I think, in this post from December about credit card debt. The key points are (1) current low demand is much more a matter of depressed consumption than depressed investment; (2) it's nonsense to say that households suffer from a shortage of safe assets since they face an infinitely-elastic supply of government-guaranteed bank deposits, the safest, most liquid asset there is; (3) while it's possible in principle for a safe-asset shortage to show up as an unwillingness of financial intermediaries to hold household debt, the evidence is overwhelming that the fall in household borrowing is driven by demand, not supply. The entire fall in credit card debt is accounted for by defaults and reduced applications; the proportion of credit card applications accepted, and the average balance per card, have not fallen at all.