Kelton and Krugman on IS-LM and MMT

The MMT debates continue apace. New critiques — the good, the bad and the ugly — appear daily. Amidst the chaos, a guest post on Alphaville from three MMT authors stood out: the piece responded directly to various criticisms while discussing the policy challenges associated with controlling demand and inflation when fiscal policy is the primary macro stabilisation tool. These are the debates we should be having.

Unfortunately, it is one step forward, two steps backwards: elsewhere Stephanie Kelton and Paul Krugman have been debating across the pages of the Bloomberg and the New York Times websites. The debate is, to put it politely, a mess.

Krugman opened proceedings with a critique of Abba Lerner’s Functional Finance: the doctrine that fiscal policy should be judged by its macroeconomic outcomes, not on whether the financing is “sound”. Lerner argued that fiscal policy should be set at a position consistent with full employment, while interest rates should be set at a rate that ensures “the most desirable level of investment”. Krugman correctly notes the lack of precision in Lerner’s statement on interest rates. He then argues that, “Lerner neglected the tradeoff between monetary and fiscal policy”, and that if the rate of interest on government debt exceeds the rate of growth, either the debt to GDP ratio spirals out of control or the government is forced to tighten fiscal policy.

Kelton hit back, arguing that Krugman’s concerns are misplaced because interest rates are a policy variable: the central bank can set them at whatever level it likes. Kelton points out that Krugman is assuming a “crowding out” effect: higher deficits lead to higher interest rates. Kelton argues that instead of “crowding out”, Lerner was concerned about “crowding in”: the “danger” that government deficits would push down the rate of interest, stimulating too much investment. Putting aside whether this is an accurate description of Lerner’s view, MMT does diverge from Lerner on this issue: since MMT rejects a clear link between interest rates and investment, the MMT proposal is simply to set interest rates at a low level, or even zero, and leave them there.

So far, this looks like a straightforward disagreement about the relationship between government deficits and interest rates: Krugman says deficits cause higher interest rates, Kelton says they cause lower interest rates (although she also says interest rates are a policy variable — this apparent tension in Kelton’s position is resolved later on)

Krugman responded. This is where the debate starts to get messy. Krugman takes issue with the claim that the deficit should be set at the level consistent with full employment. He argues that at different rates of interest there will be different levels of private sector spending, implying that the fiscal position consistent with full employment varies with the rate of interest. As a result, the rate of interest isn’t a pure policy variable: there is a tradeoff between monetary and fiscal policy: with a larger deficit, interest rates must be higher, “crowding out” private investment spending.

Krugman’s argument involves two assumptions: 1) there exists a direct causal relationship between the rate of interest and the level of private investment expenditure, and, 2) the central bank will react to employment above “full employment” with higher interest rates. He illustrates this using an IS curve and a vertical “full employment” line (see below). He declares that “this all seems clear to me, and hard to argue with”.

250219krugman1-jumbo

At this point the debate still appears to remain focused on the core question: do government deficits raise or lower the rate of interest? By now, Krugman is baffled with Kelton’s responses:

It seems as if she’s saying that deficits necessarily lead to an increase in the monetary base, that expansionary fiscal policy is automatically expansionary monetary policy. But that is so obviously untrue – think of the loose fiscal/tight money combination in the 1980s – that I hope she means something different. Yet I can’t figure out what that different thing might be.

This highlights two issues: first, how little of MMT Krugman has bothered to absorb, and, second, how little MMTers appear to care about engaging others in a clear debate. Kelton, following the MMT line, is tacitly assuming that all deficits are monetised and that issuing bonds is an additional, and possibly unnecessary, “sterilisation” operation. Under these assumptions, deficits will automatically lead to an increase in central bank reserves and therefore to a fall in the money market rate of interest. But Kelton at no point makes these assumptions explicit. To most people, a government deficit implicitly means bond issuance, in correspondence with the historical facts.

So Krugman and Kelton have two differences in assumptions that matter here. First, Krugman assumes a mechanical relationship between interest rates and investment and thus a downward sloping IS curve, while Kelton rejects this relationship. Second, they are assuming different central bank behaviour. Krugman assumes that the central bank will react to fiscal expansion with tighter monetary policy in the form of higher interest rates: the central bank won’t allow employment to exceed the “full employment” level. Kelton assumes, firstly, that fiscal policy can be set at the “full employment” level, without any direct implications for interest rates and, secondly, that deficits are monetised so that money market rates fall as the deficit expands.

The “debate” heads downhill from here. Krugman asks several direct questions, including “[does] expansionary fiscal policy actually reduce interest rates?”. Kelton responds, “Answer: Yes. Pumping money into the economy increases bank reserves and reduces banks’ bids for federal funds. Any banker will tell you this.” Even now, neither party seems to have identified the difference in assumptions about central bank behaviour.

The debate then shifts to IS-LM. Krugman asks if Kelton accepts the overall framework of discussion — the one he previously noted “all seems clear to me, and hard to argue with”. Kelton responds that, no, MMT rejects IS-LM because it is “not stock-flow consistent”, while also correctly noting that Krugman simply assumes that investment is a mechanical function of the rate of interest.

In fact, Krugman isn’t even using an IS-LM model — he has no LM curve — so the “not stock flow consistent” response is off target. The stock-flow issue in IS-LM derives from the fact that the model solves for an equilibrium between equations for the stock of money (LM), and investment and saving (IS) which are flow variables. But without the LM curve it is a pure flow model: Krugman is assuming, as does Kelton, that the central bank sets the rate of interest directly. So Kelton’s claim that “his model assumes a fixed money supply, which paves the way for the crowding-out effect!” is incorrect.

Similarly, Kelton’s earlier statement that Krugman “subscribes to the idea that monetary policy should target an invisible ‘neutral rate'” makes little sense in the context of Krugman’s IS model: there is no “invisible” r* in a simple IS model of the type Krugman is using: the full employment rate of interest can be read straight off the diagram for any given fiscal position.

Krugman then took to Twitter, calling Kelton’s response “a mess”, while still apparently failing to spot that they are talking at cross purposes. Kelton hit back again arguing that,

The crude, IS-LM interpretation of Keynes demonstrates that, under normal conditions, an increase in deficit spending will push up interest rates and lead to some crowding-out of investment spending. There is no room for a technical analysis of monetary operations in that framework.

Can this discussion be rescued? Can MMT and IS-LM be reconciled? The answer, I think, turns out to be, “yes, sort of”.

I wasn’t the only person pondering this question: several people on Twitter went back to this post by Nick Rowe where he tries to “reverse engineer” MMT using the IS-LM model, and comes up with the following diagram:

Rowe-IS-LM
Does this help? I think it does. In fact, this is exactly the diagram used by Victoria Chick in 1973, in The Theory of Monetary Policy, to describe what she calls the “extreme Keynesian model” (bottom right):

Chick-Theory-Monetary-Policy-scaled

So how do we use this diagram to resolve the Krugman-Kelton debate? Before answering, it should be noted that MMTers are correct to point out problems with the IS-LM framework. Some are listed in this article by Mario Seccareccia and Marc Lavoie who conclude that IS-LM should be rejected, but “if one were to hold one’s nose,” the “least worst” configuration is what Chick calls the “extreme Keynesian” version.

To see how we resolve the debate, and at the risk of repeating myself, recall that Krugman and Kelton are talking about two different central bank reactions. In Krugman’s IS model, the central bank reacts to looser fiscal policy with higher interest rates. Kelton, on the other hand, is talking about how deficit monetisation lowers the overnight money market rate. Kelton’s claim that a government deficit reduces “interest rates” is largely meaningless: it is just a truism. Flooding the overnight markets with liquidity will quickly push the rate of interest to zero, or whatever rate of interest the central bank pays on reserve balances. It is a central bank policy choice: the opposite of the one assumed by Krugman.

But what effect will this have on the interest rates which really matter for investment and debt sustainability: the rates on corporate and government debt? The answer is “it depends” — there are far too many factors involved to posit a direct mechanical relationship.

This brings a problem that is lurking in the background into sight. Both Kelton and Krugman are talking about “interest rates” or “the interest rate” as if there were a single rate of interest, or that all rates move together — the yield curve shifts bodily with movements of the policy rate. As the chart below shows, even for government debt alone this is a problematic assumption.

Now, in the original IS-LM model, the LM curve is supposed to show how changes in the government controlled “money supply” affects the long term bond rate of interest. This is because, for Keynes, the rate of interest is the price of liquidity: by giving up liquidity (money) in favour of bonds, investors are rewarded with interest payments. But the problem with this is that we know that central banks don’t set the “money supply”: they set a rate of interest. So, it has become customary to draw a horizontal MP curve, allegedly representing an elastic supply of money at the rate of interest set by the central bank. But note that in switching from a sloping to a horizontal LM curve, the “interest rate” has switched from the long bond rate to the rate set by the central bank.

So how is the long bond rate determined in the horizontal MP model? The answer is it isn’t. As in the more contemporary three-equation IS-AS-MP formulation, it is just assumed that the central bank fixes the rate of interest that determines total spending. In switching from the upward sloping LM curve to a horizontal MP curve, the crude approximation to the yield curve in the older model is eliminated.

What of the IS curve? Kelton is right that a mechanical relationship between interest rates and investment (and saving) behaviour is highly dubious. If we assume that demand is completely interest-inelastic, then we arrive at the “extreme Keynesian” vertical IS curve. But does Kelton really think that sharp Fed rate hikes will have no effect on total spending? I doubt it. As Seccareccia and Lavoie note, once the effects of interest rates on the housing market are included, a sloping-but-steep IS curve seems plausible.

Now, does the “extreme Keynesian” IS-LM model, all the heroic assumptions notwithstanding, represent the MMT assumptions? I think, very crudely, it does. The government can set fiscal policy wherever it likes, both irrespective of interest rates and without affecting interest rates: the IS curve can be placed anywhere along the horizontal axis. Likewise, the central bank can set interest rates to anything it likes, again without having any effect on total expenditure. This seems a reasonable, if highly simplified approximation to the standard MMT assumptions that fiscal policy and monetary policy can be set entirely independently of each other.

But is it useful? Not really, other than perhaps in showing the limitations of IS-LM. The only real takeaway is that we deserve a better quality of economic debate. People with the visibility and status of Kelton and Krugman should be able to identify the assumptions driving their opponent’s conclusions and hold a meaningful debate about whether these assumptions hold — without requiring some blogger to pick up the pieces.

A belated reply to Fazi and Mitchell on Brexit

Bruno Bonizzi and Jo Michell

In a Jacobin article earlier this year, Thomas Fazi and Bill Mitchell argued in favour of a hard Brexit. We published a reply, also in Jacobin. Fazi and Mitchell (FM) responded with accusations of strawman arguments, false claims, bias and muddled thinking. We intended to write a reply at the time, but other commitments got in the way. However we believe that FM’s reply was sufficiently inaccurate – and in places, dishonest – that a reply is required, even if belatedly.

Brexit predictions

In our Jacobin article we noted that pre-referendum predictions of immediate recession following a Leave vote were produced for political effect, while economists emphasised the likely longer run costs. FM dispute this interpretation, citing as evidence a letter signed by over 200 economists, warning of the likely economic effects of Brexit. One of us (Jo Michell) has some knowledge of this letter, having not only signed it but also having played a role in coordinating signatories – signatories which include a good cross-section of the UK heterodox economics community.

FM quote the letter as follows:

Focusing entirely on the economics, we consider that it would be a major mistake for the UK to leave the European Union …

The uncertainty over precisely what kind of relationship the UK would find itself in with the EU and the rest of the world would also weigh heavily for many years. In addition, there is a sizeable risk of a short-term shock to confidence if we were to see a Leave vote on June 23rd. The Bank of England has signalled this concern clearly, and we share it.

Compare FM’s edit with the original text of the letter below (our bold text).

Focusing entirely on the economics, we consider that it would be a major mistake for the UK to leave the European Union.

Leaving would entail significant long-term costs. The size of these costs would depend on the amount of control the UK chooses to exercise over such matters as free movement of labour, and the associated penalty it would pay in terms of access to the single market. The numbers calculated by the LSE’s Centre for Economic Performance, the OECD and the Treasury describe a plausible range for the scale of these costs.

Can you see what they did there?

The first substantial paragraph of the letter — conveniently deleted by FM – focuses on the long-term costs. Midway through the second paragraph, is the following sentence: “In addition, there is a sizeable risk of a short-term shock to confidence…” (our emphasis). The letter is clearly worded: we believe that Brexit entails long-term costs and, additionally, a risk of negative short-term effects.

FM also comment – referring to the first line of the letter – “And nothing ‘entirely’ economics about that. They were trying to influence the Referendum outcome in favour of Remain.”

Of course we were trying to influence the referendum outcome – that was the point of the letter – because, on the basis of the economics, we believe Brexit to be a mistake.

Finally, FM state, “This letter was published in the Times newspaper and so received widespread coverage.” This is genuinely funny. The (paywalled) letter was almost universally ignored by the UK press – to the point that Tony Yates’ frustration became a running joke on UK economics Twitter.

FM then highlight a report published by NIESR shortly before the vote. Again FM edit their quote carefully, removing the qualifier “albeit not unanimous” from the sentence “there is a degree, albeit not unanimous, of consensus that leaving the EU would depress UK economic activity in both the short term (via uncertainty) and the long term (via trade).” Aside from the quotation, FM devote no attention to the actual contents of the report, which summarises various Brexit macro modelling exercises, include the Treasury’s long term forecasts and both long and “near term” forecasts from the OECD, LSE and NIESR themselves. With the exception of the LSE modelling exercise, all are produced using NIESR’s NiGEM model.

What do the projections show? First note that the “near term” projections run until 2020, while the longer term projections run till 2030. The long-run projections of a hard Brexit do indeed predict a large hit to GDP. The shorter run scenarios suggest a smaller hit to GDP, of between 2.6% and 3.3%, by 2020. Does this prove, as FM argue, that economists “catastrophically failed in relation to the short-run impacts of the Brexit vote”?

At risk of stating the obvious, 2020 is four and half years after the referendum vote and beyond the Article 50 period: Brexit will have happened (this is the assumption in the projections, anyway). A 3% hit to GDP by 2020 seems perfectly plausible. But saying something is plausible is not the same as saying it is certain. In the case of both the economists’ letter to the Times and FM’s next piece of evidence, an Observer poll of economists, FM choose to ignore a crucial word: risk. Stating that there is a risk something will happen is not the same as saying it will happen. Fazi is a journalist. But Mitchell, an economics professor, really should understand the distinction between risk and certainty.

So, what of those statements that a hard Brexit increases the risk of a negative economic shock by 2020? Is the projection of 3% hit to GDP by 2020 in the wake a no-deal Brexit a “catastrophic failure”? How is the UK doing since the referendum?

GDP growth came to a halt in the first quarter of 2018 after declining steadily in the wake of the Brexit vote. Despite a bounce back in the summer, the UK growth rate is currently the lowest of the G7 economies. Of course, we don’t have the counterfactual — and since UK growth is pretty much entirely dependent on household spending, consumer credit and retail, this slowdown could have come at almost any point. But with the household savings rate and net lending now negative — and clearly unsustainable — further reductions in consumer demand seem inevitable.

What of manufacturing – the great hope of the pro-Brexit Left? Corbyn recently made the case that pound devaluation in the wake of Brexit will lead to a revival of manufacturing. But the UK pound has been depreciating for decades — alongside a widening current account deficit and a steady decline in manufacturing. Investment spending in car manufacturing has halved since the Brexit vote. Several major manufacturers including BMW, Siemens and Airbus have warned that they will cease manufacturing in the UK in the event of a hard Brexit. The Society of Motor Manufacturers and Traders (SMMT) issued a warning that 860,000 skilled manufacturing jobs are at risk in the event of a hard brexit. Leaked government reports predict that low-income, Leave-voting ex-manufacturing areas of the UK will be hardest hit by a hard Brexit. This week, the European boss of Ford warned that a no-deal Brexit would be “disastrous” for UK manufacturing. AstraZeneca has announced a freeze in manufacturing investment in the UK. We could go on.

Booming Brexit Britain?

In our original reply to FM, we took issue with their attempt to paint the post-referendum period as a boom. FM claim we have misrepresented them: “to their discredit, Bonizzi and Michell are just making stuff up when they make that claim about us.” Here is the section of FM’s original article we referred to:

UK exports are at their strongest position since 2000. As the Economist recently put it: “Britain’s long-suffering makers are enjoying a once-in-a-generation boom,” as the shifts induced by Brexit engender a much-needed “rebalancing” from boom-and-bust financial services towards manufacturing. This is also spurring a growth in investment. Total investment spending in the UK — which includes both public and private investment — was the highest of any G7 country during 2017: 4 percent compared to the previous year.

The reader can decide if we are “just making stuff up”.

Having attacked us for our interpretation of the above quote, FM even go on, without a hint of irony, to quote the same Economist sentence – arguing that pound devaluation and growing export demand has led to a “virtuous circle” in which manufacturers are experiencing a “once-in-a-generation boom … manufacturing is seeing its strongest growth since the late 1990s …”

This reinforces a point we made in our Jacobin article: FM seem to have trouble with the distinction between levels and growth rates. Manufacturing may have grown strongly in 2017 – before going into reverse and contracting at the start of 2018 – but this is in large part the result of “base effects”. Because UK manufacturing is now so small – output is still below pre-crisis levels – even small increases register as large percentage growth rates. This is not the same thing as a manufacturing “boom”.

FM made the same error in their original piece when discussing investment, where they incorrectly stated that “Total investment spending in the UK … was the highest of any G7 country during 2017” – actually it was the lowest. Now, we are prepared to accept that FM believed they were claiming that investment growth was highest – it was just a typo – but that isn’t what they wrote. Upon investigation, we discovered that FM’s error was in fact the result of carelessly pasting together two directly quoted half-sentences from the FT. Pointing out this error is not sleight of hand, and discussing base effects isn’t “throwing in some cloud” – whatever that means. (It is also good form to use quotation marks when cutting and pasting someone else’s text.)

Defenders of mainstream macro?

Next up, FM try and paint us as defenders of mainstream economics, arguing that “Bonizzi and Michell’s defense of the economics professions is thus very hard to comprehend.” This comes at the end of a long and incoherent section in which FM conflate DSGE modelling, gravity models of international trade, support for austerity and a number of other things – while, of course, stating that “it was obvious to Modern Monetary Theory (MMT) economists as early as the late 1990s that a crisis was brewing”.

FM appear to think that, because we find negative long term Brexit predictions to be plausible, we are defending every failure of economics modelling and policy over the last three decades. Clearly they haven’t bothered to check our views on this. When they conflate these issues by writing, “same models, same approach, same catastrophic errors”, they demonstrate their ignorance. DSGE macro models and gravity models may both have important flaws – but they are not the same.

Trade graphs, EU utopianism, nativism and the Irish border

There are multiple further sections in FM’s reply – on the interpretation of trade graphs, the importance of racism and the far-right, and whether the EU is a “utopia”. These are as incoherent and inaccurate as the points refuted above. To give just one more example, FM state that “… the contention by Bonizzi and Michell that the EU is the only thing preventing the UK from plunging into a quasi-fascist dystopia is untenable.” – a contention that is nowhere to be found in anything we have written. Elsewhere, FM abandon even the pretence of debate, and resort to throwing in statements like, “Hello! Is anyone there?”

FM claim – inaccurately – that in their articles and book, they have covered all the points we raise. But we raised one issue in our Jacobin article that FM conspicuously ignore in their reply: the Irish border. We wrote:

The UK government’s current position of aiming to leave the customs union without creating a hard border in Ireland is akin to a Venn diagram in which there is no intersection between the circles. For this reason, Theresa May is currently proposing two incompatible approaches, both of which are unacceptable to the EU.

As has since become overwhelmingly apparent, those who want to argue for a hard Brexit need to spell out a solution to the Irish border issue. Perhaps now would be a good time for FM to tell us theirs?

Finally, we note that in their incoherent attempt to conflate mainstream economics and opposition to Brexit, FM quote Ann Pettifor. In response to FM’s attack on us, Ann tweeted the following: “Bill Mitchell & Fazi need reminding that it is rise of nationalism & even fascism in Europe that is the threat. Progressives should lead – not walk away & vacate political space to the Far Right.”

Fazi and Mitchell have not engaged with our arguments in good faith. Their attack is not a serious attempt to engage in debate or respond to the points we raised. In a number of places it is transparently dishonest. Anyone who follows Fazi and Mitchell’s lead on these crucial issues should take a long hard look.