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August 2011, EB11-08

Economic Brief
Is Stimulative Fiscal Policy More Effective
at the Zero Lower Bound?
By Renee Haltom and Pierre-Daniel G. Sarte

Several recent research efforts have found that stimulative fiscal policy—
government spending or tax cuts—can have unusual effects when nominal
interest rates are as low as they are today. In particular, some studies have
found that the government spending “multiplier” can be much larger at the
zero lower bound. Despite these results, some caution is due when interpreting the size of the fiscal multiplier.
When it comes to treating recessions, academic research in recent years has focused largely
on monetary policy, with fiscal policy receiving
relatively scant attention. Government spending surges or tax breaks can take a long time
to be approved and implemented. Alternatively, monetary policy, through adjustments
to short-term interest rates, is perceived to be
effective given its important effect on expectations. In particular, the case for monetary
policy as the primary recession-fighting tool
was bolstered by its apparent success during
the Great Moderation extending from the early
1980s to 2007 (though good luck regarding
the lack of devastating shocks to the economy
likely played a role in that success).
But what if monetary policymakers cannot
lower interest rates further to fight an ongoing recession? Since early December 2008, the
Fed’s policy interest rate, the federal funds
rate, has been as low as it can go: the zero
lower bound (ZLB). The ZLB is a rare event;
aside from the recent episode, the United
States had never confronted it in its post-World
War II history.1

EB11-08 - The Federal Reserve Bank of Richmond

The deep recession of 2007–09 led policymakers
to turn to fiscal policy, passing the 2009 American Recovery and Reinvestment Act (ARRA), a
major fiscal stimulus effort. Economists differed
widely in their assessments of the ARRA’s desirability and, since it has been implemented, its
efficacy. A revived debate emerged over fiscal
policy in the unique setting of the ZLB.
Intuitively, there are reasons to suspect that the
economy might exhibit unique dynamics at the
ZLB. Very low interest rates are more likely to be
associated with deflationary conditions, which
the central bank has fewer options to treat at
the ZLB. If deflation is expected while at the
ZLB, the real interest rate—the nominal interest
rate adjusted for inflation—could rise, perversely
reducing consumption in an already weak
economic environment.
It is very rare for an economy to be at the ZLB,
so there is relatively little real-world experience
that economists can use to analyze the effects of
fiscal policy in that state. This makes theoretical
research—in which such an environment can be
artificially constructed—an especially useful tool.

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To understand why fiscal policy might operate differently at the ZLB, it is useful to first revisit the mechanism of fiscal policy in “normal” times—that is, when
nominal interest rates are well above zero.
Fiscal policy in “normal” times
The efficacy of fiscal policy is often discussed in the
context of one question: How big is the multiplier?
The multiplier is the change in output resulting from
an increase in government spending or tax cuts. A
multiplier of one implies that the net effect of each
dollar of government spending is to raise GDP by
one dollar. When the multiplier is negative, in contrast, government spending is associated with a
reduction in output.
In a seminal paper, Baxter and King (1993), hereafter
BK, analyze fiscal policy in a neoclassical setting—
that is, one where there are no “frictions,” which in
this context means that government spending is
financed by lump-sum taxes and prices are perfectly
flexible.2 The first assumption provides an environment in which the government’s choice of funding
method does not distort households’ behavior and,
therefore, the net effects of the stimulus. The flexibleprice assumption in the environment provided by BK
implies that the model includes no role for monetary
policy or a central bank. Since their model includes
no role for the central bank, it cannot explore the
implications of the ZLB for fiscal policy.
In the BK model, the average person must choose
how to allocate his or her time between work and
leisure. The economy’s total output is composed of
consumption, investment, and government spending, and resources are fixed in the short run: When
the government consumes the economy’s resources,
either consumption or investment, or both, must
decrease. (Hereafter, we hold investment constant to
simplify the analysis.)
BK considers a temporary, unanticipated increase in
government purchases. The increase has two competing effects: Government purchases are funded by
taxes, so they reduce the average person’s income by
the same amount. Households feel poorer, so they
consume less. But another effect of households feel-

ing poorer is that they choose to work more. (In the
parlance of economic theory, both consumption and
leisure are “normal” goods in that they fall when income decreases). The increased labor supply boosts
production and output. The fact that labor supply
increases when households feel poorer is known as
a “wealth effect.”
The net effect of government purchases in the BK
model under plausible calibrations—that is, values of
parameters that make the model consistent with key
historical behaviors of the economy—is a multiplier
of less than one in most cases. To see why, recall that
the net change in output must equal the combined
changes in its components, which include government spending and consumption. The change in
consumption is negative and lower in magnitude
than the immediate increase in government spending since economic theory suggests that households
will smooth the hit to consumption over many periods. Therefore, the total increase in output must be
less than the increase in government spending.
Accounting for nominal rigidities
The BK result applies to a frictionless environment.
However, today’s conventional models include “New
Keynesian” nominal rigidities, such as sticky prices
(prices that fail to adjust instantaneously to changes
in the economy). Price rigidity implies a potential role
for the central bank in the sense that changes in monetary policy can lead to changes in “real” economic
variables, like output and employment, in the short
run. It turns out that adding this complication does
not dramatically change the multiplier estimates.
Christiano, Eichenbaum, and Rebelo (2011), hereafter
CER, analyze fiscal policy in a New Keynesian setting.3
The central bank is assumed to set monetary policy
by following a standard Taylor rule, in which it sets
nominal interest rates by weighing the relative performances of inflation and employment. Like the BK
model, the wealth effect in response to a sudden increase in government purchases is a key component
of the economy’s response: The taxes that finance
an increase in government purchases make households feel poorer, causing them to work more, thus
increasing output.

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But an additional effect serves to raise employment
even further in the CER model. Not all firms are able
to adjust their prices, and those that cannot adjust
must produce a disproportionate share of output
because their low relative price means they face relatively high demand. In order to meet this demand,
they have to employ more inputs. They compete for
inputs and ultimately have to pay higher prices for
them, paying higher wages to workers, for example.
Firms’ markup, the spread of prices over marginal
cost, falls. Not all goods prices have risen, but input
prices have risen, tantamount to an increase in the
real wage. The increase in the real wage induces
households to supply more labor, amplifying the rise
in employment and output induced by the wealth effect of increased government purchases alone.
CER also assume the utility people get out of an additional unit of consumption is not independent from
their labor supply, and in particular, increases with
their hours worked. This assumption captures the
notion that consumption enjoyed in rare moments of
free time is appreciated to a greater degree. This feature of the model induces people to consume more
when they work more, and potentially reverses the initial fall in consumption induced by the taxes that fund
the stimulus. Overall, in CER’s model, consumption
actually rises in response to government spending.
As before, the change in output must equal the net
change in government spending and consumption
(holding investment constant). Now that consumption responds positively, it must be the case that
the change in output is greater than the change in
government spending. In this case, therefore, the
multiplier exceeds one. (When this assumption is
relaxed, and the marginal utility of consumption no
longer rises with income, the multiplier once again
falls below one, but remains positive.)
In the CER model, the resulting sticky-price multiplier
under conventional assumptions is 1.05. CER also
show that the size of the multiplier depends on various characteristics of the economy. For example, CER
show that the multiplier grows when:
1. prices get stickier, since the markup falls more

rapidly when aggregate demand rises. (In fact, mirroring the BK result, the multiplier falls below one
when prices are perfectly flexible.);
2. the central bank is less responsive to inflationary
pressures or, viewed differently, the central bank
cooperates with fiscal policy by keeping interest
rates low in the face of fiscal expansion; and
3. the government’s spending program is shorter
lived. A relatively permanent program increases
the present value of taxes, increasing the negative
effect on consumption.
Even so, CER argue that it is difficult for a sticky-price
model with plausible calibrations to produce a multiplier greater than 1.2.
Things change at the ZLB
Many models explore the ZLB by introducing a shock
to the economy that is large enough to bring nominal interest rates to zero, such that the ZLB becomes
“binding.” As the shock causes a severe output
contraction, the Taylor rule implies that the central
bank should set a negative nominal interest rate,
which most economists regard as impossible in practice. The ZLB therefore becomes binding when the
economy hits this point, and the central bank simply
sets interest rates to zero.
The specific situation considered by CER is a shock
to households’ “discount factor,” a measure of how
patient people are with respect to consumption.
In their experiment, people start to value tomorrow’s
consumption more, increasing savings today. One
could imagine a number of real-world scenarios
that might cause this to be the case.4 People may
have formed worsening expectations of future
economic performance or simply become more
uncertain about the future. The practical effect of the
shock is that consumption falls, therefore reducing
aggregate demand.
CER show that when the ZLB is binding, the shock
causes an economic tailspin: The fall in demand
induced by lower consumption reduces competition
for inputs, causing marginal cost to decline and putting downward pressure on prices. Not all firms can
change their prices instantaneously, so households

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expect future lower prices (rather than a complete,
one-time adjustment downward). However, the
nominal interest rate is stuck at zero.
Here the real interest rate becomes critical. With
nominal interest rates at zero and prices expected
to fall, the real interest rate becomes positive: The
rewards to saving have increased. This further reinforces households’ initial desire to save, thus lowering demand even further, and so on.
The same feedback effect that produces a severe
economic contraction at the ZLB (in response to
a discount rate shock) produces a very large government spending multiplier (in response to a
government spending shock). In the CER standard
sticky-price model, an increase in aggregate demand
induced by government spending forces firms to
compete for inputs. Their markup falls, and prices are
expected to rise. With zero nominal interest rates, the
real interest rate becomes negative—households effectively are taxed by saving—thus further inducing
households to spend. The rise in spending further
increases the initial rise in aggregate demand from
government purchases.

multiplier of 0.16 (each dollar of labor tax cuts increases output by 16 cents).
However, Eggertsson finds that the multiplier for a
cut in labor taxes flips signs at the ZLB. Because nominal interest rates are stuck at zero, downward price
pressures create deflationary expectations that the
central bank is unable to address with accommodative policy. This pushes the real interest rate higher,
setting off the same feedback effect that exists in the
CER model, having a negative effect on spending.
Therefore, in Eggertsson’s model, the multiplier from
a 1 percent cut in the labor tax at the ZLB switches
from being positive to negative, at -1.02.
A temporary sales tax reduction, on the other
hand, is expansionary. It makes consumption today
cheaper relative to the future, stimulating spending.
Overall, Eggertsson’s results suggest that expansionary fiscal policy at the ZLB should avoid tax cuts that
stimulate aggregate supply—like a cut in the labor
tax—and instead favor those that stimulate aggregate demand—like a cut in the sales tax. As in the
CER model, the key mechanism is forces that create
inflationary expectations at the ZLB, therefore pushing the real interest rate below zero.

To summarize, the key mechanism underlying the
larger government spending multiplier in the CER
framework at the ZLB is the feedback effect that
produces ever lower real interest rates. When nominal interest rates are stuck at zero, that effect will be
ignited once prices are expected to rise. CER calculate a government spending multiplier at the ZLB
equal to 3.7.

Do implementation lags matter?
Government spending programs are hard to implement instantaneously. Since fiscal policy appears to
operate differently at the ZLB, it is worth exploring
whether the ZLB must be in place when stimulus
spending comes online in order for the multiplier to
remain large.

Tax cuts are another commonly cited recessionfighting tool. Eggertsson (2010) considers a model
similar to CER to investigate the effects of a tax cut.5
In normal times, tax cuts to stimulate aggregate supply are expansionary. Workers get to keep a greater
proportion of each dollar they earn, so for any given
wage, people want to work more. Firms can then
produce more cheaply, exerting downward pressure
on prices. In Eggertsson’s model, the Taylor rule leads
the central bank to respond by lowering interest
rates. After this adjustment, the model produces a

CER show that a spending program with implementation lags can produce a large multiplier today
relative to the non-ZLB case. However, critical to
this outcome is that the ZLB still be in effect when
the spending hits the economy. The effect operates through inflation expectations: An expected
increase in government spending in future periods
increases future output and inflation, and therefore
produces higher expected inflation and a lower
real interest rate today. This reduces savings and
increases consumption.

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That said, in the CER model, implementation lags
reduce the government spending multiplier at the
ZLB. Compared with an immediate ZLB multiplier of
3.7, the one-period lag multiplier falls to 1.5. However, the multiplier does not decrease quickly with
additional lags; a two-period lag still produces a
multiplier of 1.44. But, again, it is critical that the ZLB
still be in place when the spending hits the economy.
If the ZLB is no longer binding when the spending
comes online, the multiplier drops to 0.46.
The implication for policy is that if spending increases are expected to be implemented with a lag,
the stimulus may be more successful when the ZLB
is expected to be in place for some time (perhaps, for
example, when the economic contraction is very severe). However, this will only work, in the CER model,
if the government has promised in advance that it
will increase spending any time the ZLB is reached,
such that to expect a binding ZLB in the future is to
expect a stimulus program in the future.
Braun and Körber (2011) provide further evidence
of the importance of expectations to the size of the
multiplier in New Keynesian models.6 In particular,
they cast doubt on the large multipliers that New
Keynesian models produce at the ZLB. They construct an alternative model and fit it to data from
Japan’s experience with the ZLB in the late 1990s
and 2000s.7 They show that the large multipliers hold
only when households expect the ZLB to be binding
for several years. However, when households in their
model hold such expectations, the model predicts
much more volatility in the Japanese economy than
it actually experienced during that period. Braun
and Körber point to research suggesting households
expected the ZLB in Japan to bind for a shorter
period of roughly two years. When households in
their model hold such expectations, the government
spending multiplier is only 0.9. With similar expectations, they also find, contrary to Eggertsson’s result,
that a cut in labor taxes is expansionary.
What does the multiplier really tell us?
Perhaps the only thing fiscal policy literature has
determined with certainty is that there is no one
multiplier. Rather than framing the question as the

hunt for “the” multiplier, policymakers considering
fiscal stimulus ought to weigh factors that are likely
to make a proposed program effective.
To that end, there are a number of important questions to consider. Each of the studies cited here
shows that the effectiveness of fiscal policy depends
critically on the environment. A specific example
may clarify this point: As emphasized by Christiano
(2010), some of the effects described above hinge on
two assumptions: first, that downward price pressures produce deflation over time, and second, that
aggregate spending is very sensitive to the real interest rate.8 It is not clear the extent to which either of
these conditions is true in practice.
Additionally, an increase in output following fiscal
stimulus does not necessarily mean that welfare
has increased. For example, in the BK neoclassical
model without frictions, higher output is the result
of households working harder, and consumption
is permanently lower, thus households actually are
worse off than before.
There also are additional real-world costs of stimulus that may not be encompassed in the sterile
environment of a theoretical model. They include
factors such as the longer-term budgetary impact
of government programs and the degree to which
the government spends its dollars on productive
endeavors. In addition, fiscal policy can produce
well-known distortionary effects. If not properly
targeted, government spending can cause welfare
loss by displacing private economic activity.9 Additionally, the above models assume for simplicity that
fiscal policy is financed with nondistorting lump-sum
taxes. This is rarely the case in reality. Drautzburg and
Uhlig (2011) show that distortionary taxes can significantly reduce the multiplier in the long run, possibly
causing it to be negative.10
Finally, fiscal policy may not be the only stimulative
option at the ZLB. Many economists have argued
that the central bank is not powerless in this scenario. The central bank can influence longer-term interest rates by purchasing large amounts of long-term
assets, as the Fed has done.11 It can commit to

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a higher inflation target to prevent deflationary
expectations.12 There are also ways in which the
central bank could attempt to mimic the conditions
of negative nominal interest rates.13 The feasibility
and desirability of these various policy options is an
ongoing subject of debate.

7

like many countries, during the recent global financial crisis.
8

See Lawrence J. Christiano, “Comment on Eggertsson, ‘What Fiscal
Policy is Effective at Zero Interest Rates?’” Center for Quantitative
Economic Research Working Paper No. 10-06, November 2010.

9

For these reasons, the likely size of the multiplier
is only one component of the question of whether
a specific stimulative fiscal program is “worth it.”
That is, one should be cautious of drawing simple
inferences between the size of the multiplier and
whether fiscal policy is the right tool for treating a
weak economy.

Japan experienced a stagnant economy for most of the 1990s and
confronted the ZLB from much of 1999 through 2006, and again,

For a discussion from the perspective of economic efficiency,
see Kartik B. Athreya and Renee Courtois, “Recent Fiscal Policy
and the Manipulation of Aggregate Economic Activity,” Federal
Reserve Bank of Richmond Economic Brief, August 2009, no.
09-08.

10

See Thorsten Drautzburg and Harald Uhlig, “Fiscal Stimulus
and Distortionary Taxation,” NBER Working Paper No. 17111,
June 2011.

11

Renee Haltom is a writer and Pierre-Daniel G. Sarte
is a senior economist in the Research Department at
the Federal Reserve Bank of Richmond.

For an overview of this mechanism, see, Renee Courtois
Haltom and Juan Carlos Hatchondo, “How Might the Fed’s
Large-Scale Asset Purchases Lower Long-Term Interest Rates?”
Federal Reserve Bank of Richmond Economic Brief, January
2011, no. 11-01.

Endnotes
1

12

Some economists have argued that the rarity of the ZLB in part

Inflation Targets? Some Relevant Issues,” NBER Working Paper

caused the profession to misjudge the likelihood that we would

No. 17005, May 2011, also forthcoming in Federal Reserve Bank
of Richmond Economic Quarterly, Second Quarter 2011.

end up there in the recent episode. See Hess Chung, JeanPhilippe Laforte, David Reifschneider, and John C. Williams,

2

3

13

See, among others, Willem H. Buiter, “Negative Nominal Inter-

“Have We Underestimated the Likelihood and Severity of Zero

est Rates: Three Ways to Overcome the Zero Lower Bound,”

Lower Bound Events?” Federal Reserve Bank of San Francisco

North American Journal of Economics and Finance, December

Working Paper No. 2011-01, January 2011.

2009, vol. 20, no. 3, pp. 212-238; and Marvin Goodfriend,

See Marianne Baxter and Robert G. King, “Fiscal Policy in Gen-

“Overcoming the Zero Bound on Interest Rate Policy,” Journal of

eral Equilibrium,” The American Economic Review, June 1993, vol.

Money, Credit, and Banking, November 2000, Part 2, vol. 32, no.

83, no. 3, pp. 315-334.

4, pp. 1007-1035.

See Lawrence J. Christiano, Martin Eichenbaum, and Sergio
Rebelo, “When Is the Government Spending Multiplier Large?”
Journal of Political Economy, February 2011, vol. 119, no. 1, pp.
78-121.

4

See Bennett T. McCallum, “Should Central Banks Raise their

Indeed, during the recent episode, the personal savings rate

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entirety. Please credit the authors, source, and the
Federal Reserve Bank of Richmond and include the
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jumped from roughly 2 percent before the recession to a more
than 25-year high of 8.2 percent during the recession.
5

See Gauti B. Eggertsson, “What Fiscal Policy Is Effective at Zero
Interest Rates?” in NBER Macroeconomics Annual 2010, edited by
Daron Acemoglu and Michael Woodford, University of Chicago

The views expressed in this article are those of
the authors and not necessarily those of the
Federal Reserve Bank of Richmond or the Federal
Reserve System.

Press, 2011.
6

See R. Anton Braun and Lena Mareen Körber, “New Keynesian
Dynamics in a Low Interest Rate Environment,” Federal Reserve
Bank of Atlanta Working Paper No. 2011-10, May 2011.

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