Guest blog: The Integral Reviews: Paper 3 – Hall (2009)

Guest blog – The Integral Reviews: Paper 3 – Hall (2009)
by “Integral”

Reviewed: Robert Hall (2009), “By How Much Does GDP Rise If the Government Buys More Output?” NBER WP 15496

Executive summary

The average government purchases multiplier is about 0.5, taking into account empirical and structural evidence. The only way to get “large” multipliers of 1.6 is to assume a large degree of non-optimizing behavior, an inflexible wage rate, at the zero lower bound on nominal interest rates, and assuming monetary policy is completely ineffective at influencing aggregate demand but the fiscal authority retains that influence.

The key ingredients to generating a large output multiplier are sticky wages/prices, a highly countercyclical markup ratio, and “passive” monetary policy which does not counteract the fiscal expansion.

The assumptions that underlie “the effectiveness of monetary policy” (sticky prices and a countercyclical markup) also drive “the effectiveness of fiscal policy.” The two are similar in that respect.


Hall provides a convenient overview of the state of economic knowledge about the government purchases multiplier. He does this in four steps: simple regression evidence, VAR evidence, structural evidence from RBC models, and structural evidence from various sticky-price/sticky-wage models.

Empirical evidence begins with the simple OLS regression framework. Hall obtains the output multiplier by regressing the change in military expenditures (a proxy for the exogenous portion of government spending) on the change in output. He finds multipliers significantly larger than zero but less than unity, mostly in the neighborhood of one-half. This estimate of the “average multiplier” is confounded by two problems: (1) the implied multiplier be taken as a lower bound rather than an unbiased estimate due to omitted variable bias, and (2) the estimates are driven entirely by observations during WWII and the Korean War.

The VAR approach produces a range of estimates. Hall surveys five prior studies and finds that the government purchases multiplier is non-negative upon impact across all studies and consistently less than unity, but there is much variation in the exact point estimate. The VAR approach typically suffers the same omitted variable bias as OLS.

Hall then turns to a review of the structural evidence. He first shows the standard RBC result that if wages and prices are flexible, the output multiplier is essentially zero or even negative. While a useful benchmark this is not particularly useful for applied work.

Adding wage frictions forces laborers to operate off of the labor supply curve, so output could plausibly expand from an increase in government demand. Hall indeed finds that the multiplier is higher in small-scale NK models and depends on consumer behavior. With consumers pinned down by the permanent-income/life-cycle model, multipliers tend to range around 0.7. If consumers are rule-of-thumb or iiquidity constrained, one finally finds multipliers above unity, in the neighborhood of 1.7, in the presence of the zero lower bound on nominal interest rates.


The empirical evidence is plagued by persistent endogeniety and omitted-variable bias, which Hall frankly acknowledges. Identification is extraordinarily difficult in macroeconomics; as a practical matter it is impossible to untangle all of the interrelated shocks the economy experiences each year.

On the theory side, Scott Sumner would consider this entire exercise a waste of time: the Fed steers the nominal economy and acts to offset nominal shocks; government shocks are a nominal shock, so the Fed will act so as to ensure that the government expenditures multiplier is zero, plus or minus some errors in the timing of fiscal and monetary policy.

Is this a good description of the world? On average over the postwar period, a $1 exogenous change in government spending has led to a $0.50 increase in output; excluding the WWII and Korean War data drive this number down significantly. As a first-order approximation the fiscal multiplier is likely zero on average. But we don’t care about the average, we care about the marginal multiplier, at the zero bound. In that scenario, multipliers are on average higher but still below unity. A crucial open question is to what degree the monetary authority “loses control” of nominal aggregates at the zero lower bound, and to what degree fiscal policy is impacted if the monetary authority is “helpless”. (If we are in a situation where the Fed cannot move nominal aggregates, why wouldn’t Congress be similarly constrained?)

Hall’s paper does not explicitly discuss monetary policy. However, adding a monetary authority to his models would only reduce the already-low multipliers that Hall uncovers. His point, that one cannot plausibly obtain multipliers in excess of unity in a modern macro model, is already well-established even without explicitly accounting for the central bank.


Christensen’s “postmodernist mind fuck”

I have now been blogging since early October last year and I truly enjoy it. Most of my readers seem to be happy about what I write and I believe that most of my readers and commentators are quite Market Monetarist sympathies. However, there is one exception – lefty blogger Mike Sax. Yes, I called him lefty – I don’t think Mike would not disagree with this (if he called me a libertarian that would not make me angry either…). Mike is actually reading the Market Monetarist blogs and I think he pretty much understands what we are talking about. I will readily acknowledge that despite the fact that I probably disagree with 99% of what he has to say about economics and monetary theory.

Today I ran into a comment Mike wrote a couple a days ago about the debate about fiscal policy between on the one side the New Keynesian (Old Keynesians??) and on the other side the Market Monetarists  (and John Cochrane). Even though Mike is extremely critical of  my views I actually had quite a lot of fun reading it.

Here is Mike Sax (and yes, believe it or not the name of his blog is “Diary of a Republican Hater”…):

“If you want to get the endgame of this whole market monetarist phenomenon I say put down Scott Sumner and check out Lars Christensen. His post is called simply Market Monetarist, and indeed the very name of market monetarism is actually his coinage rather than Scott.

During the interminable tangent-a rather amusing three ring circus that Sumner led-Lars wrote a post called “There is no such thing as fiscal policy.” This is a pretty radical attack on fiscal policy. From Cochrane claiming that fiscal policy can’t work-till his bout face today-and Sumner saying it can never be as effective as monetary policy in reviving demand-we have Lars claiming it simply doesn’t exist.

Whoa! I guess if it doesn’t even exist we can’t use it. Ever. It’s another postmodernist mind fuck evidently. What are Cochrane and Christensen going to say to each other now? I will suggest that if you want to make any sense of market monetarism read Lars. You get it much more concisely and to the point if nothing else.

Now here is his point. In a barter economy, he tells us, there can be no fiscal stimulus. Why is this? Because, “As there is no money we can not talk about sticky prices and wages. In a barter economy you have to produce to consume. Hence, there is no such thing as recessions in a barter economy and hence no excess capacity and no unemployment. Therefore there is no need for Keynesian style fiscal policy to “boost” demand.”

Fiscal policy can redistribute income but not effect demand.

“in a barter economy fiscal policy is a purely redistributional exercise, but it will have no impact on “aggregate demand”

Ok but maybe the title of this post is wrong. It shouldn’t say there is no such thing as fiscal policy just fiscal stimulus.

The reason we believe that fiscal policy can impact demand is because of money illusion.

“for fiscal policy to influence aggregate demand we need to introduce money and sticky prices and wages in our model. This in my view demonstrates the first problem with the Keynesian thinking about fiscal policy. Keynesians do often not realise that money is completely key to how they make fiscal policy have an impact on aggregate demand.”

What NGDP targeting is meant to do is to take away money illusion by taking away this misleading effect of the velocity of money.

“Under NGDP level targeting M*V will be fixed or grow at a fixed rate. That means that we is basically back in the Arrow-Debreu world and any increase in G must lead to a similar drop in D as M*V is fixed.”

The goal of NGDP targeting therefore as Sumner, Lars, David Glasner, et al, conceive it is a return to in effect a barter economy. Money is therefore for them kind of like the root of all evil or at least original sin. Like for old fashioned philosophers appearance was the veil that led us to misapprehend true existence, so for the market monetarists, money is the veil that makes us misapprehend the truth of the economy.

Yet Lars does admit that fiscal stimulus can work or seem to work due the the Circe of money.

“lets say that the central bank is just an agent for the government and that any increase in G is fully funded by an increase in the money supply (M). Then an increase in G will lead to a similar increase in nominal income M*V. With this monetary policy reaction function “fiscal policy” is highly efficient. There is, however, just one problem. This is not really fiscal policy as the increase in nominal GDP is caused by the increase in M. The impact on nominal income would have been exactly the same if M had been increased and G had been kept constant – then the entire adjustment on the right hand side of (3) would then just have increased D.”

Yeah let’s say that. Actually I think this accurately describes the actual historical record of the Fed between the time of Marriner Eccles and the 1970 when Milton Friedman started whispering sweet nothings in Nixon’s ear.

To be sure Christensen claims that this effect is still misleading as it’s the printed money-monetary policy-that does the real heavy lifting. It would have been exactly the same had the supply of money been increased and government spending been kept constant.

In a way these claims by Lars actually straddles the line with MMTers who do actually argue that it makes no difference whether the Fed or Treasury prints the money but where they go from here is obviously more or less diametrically opposed to what the MMers do with it. The Market Monetarists vs. The Modern Monetary Theorists… Talk about a battle royale.

Again though Lars should call this “There is no such thing as fiscal stimulus.” It seems to me though that even if you believe that fiscal stimulus is a fiction it may nevertheless have proved to be as the belief in God once was.

For what’s curious is during the time we believed fiscal stimulus we had the Keynesian era. Since we gave it up we have had an anti-Keynesian era. During this anti-K ear we have seen the wages of median Americans stagnate. Is this all coincidence? What do you think?

In any case Sumner’s oft repeated argument that the fiscal multiplier is roughly zero because any fiscal stimulus will be followed by monetary tightening according to Lars depends on the policy of the Fed. It wasn’t true during the Keynesian ear. However in this anti inflation era, post Volcker and of the Taylor Rule-the much lauded Great Moderation-it is true of how the Fed has in fact acted. This doesn’t prove that fiscal stimulus doesn’t work but rather the Fed is off the rails and probably could use the kind of reforms Barney Frank wanted for it. Namely not ending the Fed as Ron Paul says but rather ending its “independence.””

Frankly speaking, Mike of course have no clue about economics, but he is 100% right – I should of course have said that there is no such thing as fiscal stimulus (and not policy), but then he would have had nothing to write about. Mike don’t know this, but I hate everything “postmodernist” so he succeed with his low blow.

Anyway, let me say it again fiscal policy is not important. People like Paul Krugman (and Mike Sax) think that we need massive fiscal stimulus to take us out of the slump in Europe and the US and some think (for example European policy makers) think that the only solution is fiscal austerity. I think both parties are wrong – lets fix monetary policy and then we don’t have to worry (too much) about fiscal policy (other than balancing the government budgets in the medium to long run…). This is why I find it so utterly borrowing to discuss fiscal policy…

PS Mike mentions Battle Royal…he is unaware that that is my favourite Japanese movie.

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