Why Ricardian equivalence is false and expansionary policies might work

15 oktober, 2011 kl. 16:36 | Publicerat i Economics | Kommentarer inaktiverade för Why Ricardian equivalence is false and expansionary policies might work

Paul Krugman has a nice piece today on what’s wrong with Ricardian equivalence. Commenting on the paper by John Kay that I wrote about the other day here on docendo discimus, he writes:

It’s one thing to have an argument about whether consumers are perfectly rational and have perfect access to the capital markets; it’s another to have the big advocates of all that perfection not understand the implications of their own model.

So let me try this one more time.

Here’s what we agree on: if consumers have perfect foresight, live forever, have perfect access to capital markets, etc., then they will take into account the expected future burden of taxes to pay for government spending. If the government introduces a new program that will spend $100 billion a year forever, then taxes must ultimately go up by the present-value equivalent of $100 billion forever. Assume that consumers want to reduce consumption by the same amount every year to offset this tax burden; then consumer spending will fall by $100 billion per year to compensate, wiping out any expansionary effect of the government spending.

But suppose that the increase in government spending is temporary, not permanent — that it will increase spending by $100 billion per year for only 1 or 2 years, not forever. This clearly implies a lower future tax burden than $100 billion a year forever, and therefore implies a fall in consumer spending of less than $100 billion per year. So the spending program IS expansionary in this case, EVEN IF you have full Ricardian equivalence.

Is that explanation clear enough to get through? Is there anybody out there?

And the answer is that there isn’t.

The fact that these guys don’t even get the implications of their own models right tells us that the problem runs deeper than believing too much in abstract math. At some level it has to be political: they want to declare government policy ineffectual so badly that for all their vaunted modeling mojo they can’t be bothered to think it through, or listen to other people who point out their error.

As I see it Ricardian equivalence is false mainly because it requires rational expectations. As Kevin Hoover has it in his The New Classical Macroeconomics (Basil Blackwell 1988):

Ricardian equivalence is the claim that whether a given path of government expenditure is financed through taxes or debt is unimportant: substituting debt for taxes appears to increase disposable income today. But since the debt must be repaid with interest, a rational taxpayer would save the entire windfall in order to afford the future tax bill, leaving his expenditure unchanged. Ricardian equivalence remains controversial because it depends on assumptions about the public’s foresight and grasp of the fiscal system closely related to the rational-expectations hypothesis and on debatable assumptions about the incidence of taxes and expenditure.

A rather ironic fact is that Ricardo himself didn’t believe in Ricardian equivalence. In “Essay on the Funding System” (1820) he writes:

But the people who paid the taxes never so estimate them, and therefore do not manage their private affairs accordingly. We are too apt to think that the war is burdensome only in proportion to what we are at the moment called to pay for it in taxes, without reflecting on the probable duration of such taxes. It would be difficult to convince a man possessed of £20,000, or any other sum, that a perpetual payment of £50 per annum was equally burdensome with a single tax of £1000.

[For more on this issue: https://larspsyll.wordpress.com/2011/05/16/robert-lucas-rational-expectations-and-the-understanding-of-business-cycles/ ]

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