I don't know if most people realize how much credit card debt fell during and after the Great Recession. It fell by a lot! Credit card debt outstanding today is about $180 billion, or 21 percent, lower than it was at the end of 2007. This is a 50 percent larger fall than in mortgage debt in percentage terms -- though the fall in mortgages is of course much bigger in absolute dollars.
This fall in credit card debt is entirely explained by the drop in the number of credit card accounts, from about 500 million to 380 million. The average balance on open credit card accounts is about the same today as it was when the recession began.
Here's some interesting data that helps shed light on this question, from the Fed's most recent Quarterly Report on Household Credit and Finance.
The red line shows the number of credit card accounts closed over the preceding 12 months, while the blue line shows the number opened. So the gap between the blue and red lines equals the change in the number of accounts. The spike in the red line is mostly write-offs, or defaults. I'll return to those in a subsequent post; for now let's look at the blue and green lines. The green line shows the number of inquiries, that is, applications for new cards by consumers. The blue line, again, shows the number issued. As we can see, the number of new accounts tracks the number of inquiries almost exactly.  What do we conclude from this? That the fall in the rate at which new credit cards are issued is entirely a matter of reduced demand, not supply. And given that balances on outstanding credit cards have not fallen, it's hard to avoid the conclusion that banks' reduced willingness to lend played little or no role in the fall in consumer credit.
Of course one figure isn't dispositive, and mortgage debt is much more important quantitatively than credit card debt. But Dean Baker has been making a similar argument about mortgages for several years now:
the ratio of applications to [home] sales has not risen notably in this slump, indicating that the inability of potential homebuyers to get mortgages has not been a big factor in the housing downturn.As a matter of fact, after reading that post (or one of Dean's many others making the same point), I tried to construct a similar ratio for credit cards, but I wasn't able to find the data. I didn't realize then that the Fed publishes it regularly in the household credit report.
Needless to say, the ratio of applications to contracts is hardly the last word on this question, and needless to say there are plenty of more sophisticated attempts out there to disentangle the roles of supply and demand in the fall in borrowing. Rather than get into the data issues in more detail right now, I want to talk about what is at stake. Does it matter whether a fall in borrowing is more driven by the supply of credit or the demand for it? I think it does, both for theory and for policy.
One important question, of course, is the historical one: Did the financial crisis straightforwardly cause the recession by cutting off the supply of credit for nonfinancial borrowers, or were other factors more important? I admit to being agnostic on this question -- I do think that credit constraints were dragging down fixed investment in the year or so before the recession officially began, but I'm not sure how important this was quantitatively. But setting aside the historical question, we also need to ask, is the availability of credit the binding constraint on real activity today?
For monetarists and New Keynesians, the answer has to be Yes almost by definition. Here's DeLong:
There is indeed a "fundamental" configuration of asset prices--one that produces full employment, the optimal level of investment given the time preference of economic agents and the expected future growth of the economy, and the optimal division of investment between safe, moderately risky, and blue-sky projects.
However, right now the private market cannot deliver this "fundamental" configuration of asset prices. The aftermath of the financial crisis has left us without sufficient trusted financial intermediaries ... no private-sector agent can create the safe securities that patient and prudent investors wish to hold. The overleverage left in the aftermath of the financial crisis has left a good many investors and financial intermediaries petrified of losing all their money and being forced to exit the game--hence the risk tolerance of the private sector is depressed far below levels that are appropriate given the fundamentals... Until this overleverage is worked off, the private marketplace left to its own will deliver a price of safe assets far above fundamentals ... and a level of investment and thus of employment far below the economy's sustainable and optimal equilibrium.
In such a situation, by issuing safe assets--and thus raising their supply--the government pushes the price of safe assets down and thus closer to its proper fundamental equilibrium value.In other words, there is a unique, stable, optimal equilibrium for the macroeconomy. All agents know their expected lifetime income and preferred expenditures in that equilibrium. The only reason we are not there, is if some market fails to clear. If there is a shortfall of demand for currently produced output, then there must be excess demand for some asset the private sector cannot produce. In the monetarist version of the story, that asset is money.  In DeLong's version, it's "safe assets" more generally. But the logic is the same.
This is why DeLong is so confident that continued zero interest rates and QE must work -- that it is literally impossible for output to remain below potential if the Fed follows its stated policy for the next three years. If the only reason for the economy to be off its unique, optimal growth path is excess demand for safe assets, then a sufficient increase in the supply of safe assets has to be able to get us back onto it.
But is this right?
Note that in the passage above, DeLong refers to a depressed "level of investment and thus of employment." That's how we're accustomed to think about demand shortfalls, and most of the time it's a reasonable shorthand -- investment (business and residential) generally does drive fluctuations in demand. But it's not so clear that this is true of the current situation. Here, check this out:
We're looking at output relative to potential for GDP and its components; I've defined potential as 2.5 percent real annual growth from the 2007Q4 peak.  What we see here is investment and consumption both fell during the recession proper, but since 2010, investment has recovered strongly and is almost back to trend. The continued output gap is mainly accounted for by the failure of consumption to show any signs of returning to trend -- if anything, consumption growth has decelerated further in the recovery.
You can't explain low household consumption demand in terms of a shortage of safe assets. The safest, most liquid asset available to households is bank deposits, and the supply of these is perfectly elastic. I should note that it is possible (though not necessarily correct) to explain falling consumption this way for the early 1930s, when people were trying to withdraw their savings from banks and convert them into cash. The private sector cannot print bills or mint coins. But classical bank runs are no longer a thing; people are not trying to literally hoard cash; it is impossible that a lack of safe savings vehicles for households is what's holding down consumption today.
So if we are going to explain the continued consumption shortfall in DeLong's preferred terms, households must be credit-constrained. It is not plausible that households are restricting consumption in order to bid up the price of some money-like asset in fixed supply. But it is plausible that the lack of trusted financial intermediaries makes investors less willing to hold households' debt, and that this is limiting some households' ability to borrow and thus their consumption. In that case, it could be that increasing the supply of safe assets will provide enough of a cushion that investors are again willing to hold risky assets like household debt, and this will allow households to return to their optimal consumption path. That's the only way DeLong's story works.
It's plausible, yes; but is it true? The credit card data is evidence that, no, it is not. If you believe the evidence of that first figure, the fall in consumer borrowing is driven by demand, not supply; continued weakness in consumption is not the result of unwillingness of investors to hold household debt due to excess demand for safe assets. If you believe the figure, investors are no less willing to hold consumer debt than they were before the recession; it's households that are less willing to borrow.
Again, one figure isn't dispositive. But what I really want to establish is the logical point: The shortage-of-safe-assets explanation of the continued output gap, and the corollary belief in the efficacy of monetary policy, only makes sense if the weakness in nonfinancial units' expenditure is due to continued tightness of credit constraints. So every additional piece of evidence that low consumption (and investment, though again investment is not especially low) is not due to credit constraints, is another nail in the coffin of the shortage-of-safe-assets story.
So what's the alternative? Well, that's beyond the scope of this post. But basically, it's this. Rather than assume there is a unique, stable, optimal equilibrium, we say that the macroeconomy has multiple equilibria and/or divergent adjustment dynamics. More specifically, we emphasize the positive feedback between current income and expenditure. For small deviations in income, people and businesses don't adjust their expenditure, but use credit and and/or liquid assets to maintain it at its normal level. But for large deviations, this buffering no longer takes place, both because of financing constraints and because true lifetime income is uncertain, so people's beliefs about it change in response to changes in current income.
In other word's Axel Leijonhufvud's "corridor of stability". Within certain bounds (the corridor), the economy experiences stabilizing feedback, based on relative prices; beyond them, it experiences destabilizing feedback based on the income-expenditure link. Within these bounds, the multiplier is weak; outside them, it is "strong enough for effects of shocks to be endogenously amplified. Within the corridor, the prescription is in favor of 'monetarist,' outside in favor of 'fiscalist', policy prescriptions."
I'm going to break that thought off here. The important point for now is that if you think that the continued depressed level of real economic activity is due to excess demand for safe assets, you really need evidence that the expenditure of households and businesses is limited by the unwillingness of investors to hold their liabilities, i.e. that they face credit constraints. And this credit card data is one more piece of evidence that they don't. Which, among other things, makes it less likely that central bank interventions to remove risk from the balance sheets of the financial system will meaningfully boost output and employment.
 For some reason, inquiries are given over the past six months while the other two series are given over the past year. This implies that about half of all inquiries result in a new account being opened. The important point for our purposes is that this fraction did not change at all during the financial crisis and recession.
 To be fair, you can also find this story in the General Theory -- "unemployment develops because people want the moon," etc. But it's not the only story you can find there. And, I would argue, Keynes really intends this as a story of how downturns begin, and not why they persist.
 Yes, it would be more "correct" to use the BEA's measure of potential output. But the results would be qualitatively very similar, and I don't think there's nearly enough precision in measures of potential output to make the few tenths of a point difference meaningful.
LATE UPDATE: Here is a similar graph for the previous recession & recovery.