Winner of the New Statesman SPERI Prize in Political Economy 2016


Showing posts with label heterodox. Show all posts
Showing posts with label heterodox. Show all posts

Wednesday, 15 August 2018

Interest rate vs fiscal policy stabilisation


One divide between mainstream and many heterodox economists is on whether monetary or fiscal policy should be used for macroeconomic stabilisation (controlling demand to influence inflation and output). What makes a good instrument in this context? As I have argued before, a key difference between the mainstream and MMT involves different answers to this question. I think the following issues are critical.

  1. How quickly do changes in the instrument (e.g. increases in interest rates) influence demand?

  2. How quickly can the instrument be changed? Are there limits to how far it can be changed?

  3. How reliable is the impact of the instrument on demand? In other words how uncertain is the impact of a change in the instrument on demand?

  4. How certain can we be that whoever has power over the instrument will use it in the necessary way?

  5. Does changing the instrument have ‘side effects’ which are undesirable?

If we apply these questions to whether to use interest rates or some element of fiscal policy, what answer do we get?

Before doing that, it is worth noting this is all about the quickest and most reliable way to influence demand. It is quite separate to how demand influences inflation (as long as we are talking about underlying inflation).

The first question is important because long lags between changing the instrument and it influencing demand mess up good policymaking. Imagine how good your central heating would be if there was a day’s delay between it getting cold and the heating coming on. It is also perhaps the most interesting question for a macroeconomist. A full discussion would take a textbook, so to avoid that I’m going to suggest that the answer is not critical to why the mainstream prefers monetary to fiscal stabilisation.   

The second question is as important for obvious reasons. If an instrument can only be changed every year, that is like having very long lags before the instrument has an effect. On this question monetary policy seems to have a clear advantage given current institutional arrangements. Some of this difference is difficult to change: it takes time for a bureaucracy to move. As I noted with the fiscal expansion implemented by China after the crisis, about half of the projects were underway within a year. Others delays are in principle easier to change: there is no reason why tax changes need only happen during Budgets in the UK, for example.

The second part of the second question is a clear negative for interest rates, because they have a lower bound. This is not the case for fiscal instruments: you can always cut taxes further for example. Because this is a critical failure for interest rate policy, effectively the discussion in this post is just about what happens when interest rates are not at the lower bound. Even so, potentially having two different instruments for different situations is a count against monetary policy.

The third question is often not asked, but it is absolutely critical. Imagine raising the temperature on a room thermostat which not only had no calibration, but which acted in different ways each day or even each hour. OMT is a clear example of a poor instrument because central banks have far less idea of how effective it is than interest rate changes, partly because of less data but also because of likely non-linearities.

Are interest rate changes more or less reliable than fiscal changes? The big advantage of government spending changes is that their direct impact on demand is known, but as we have already noted such measures are slow to implement. Tax changes are quicker to makes, but many mainstream economists would argue that their impact is no more reliable than the impact of interest rate changes. In contrast some heterodox economists (especially MMTers) would argue interest rate changes are so unreliable even the sign of the impact is unclear.

The fourth question is only relevant if the power to change interest rates is delegated to central banks. Let me assume we have a UK type situation, where the central bank has control over interest rates but it has to follow a mandate set by the government. A strong argument is that, by delegating the task of achieving that mandate to an independent institution, policy is less likely to be influenced extraneous factors (e.g. there is no way interest rates rise until after the party conference/election) and therefore policy becomes more credible. (There is a whole literature involving similar ideas.)

This advantage for monetary policy simply follows from the fact that it can be easily delegated. However even if it is not delegated, fiscal policy has the disadvantage that changes are either popular (e,g, tax cuts) or unpopular (tax rises). In contrast interest rate changes involve gains for some and losses for others. That makes politicians reluctant to take deflationary fiscal action, and too keen to take inflationary fiscal action. So even without delegation, it seems likely that interest rate changes are more likely to be used appropriately to manage demand than fiscal changes.

The fifth and final issue could involve many things. In basic New Keynesian models the real interest rate is the price that ensures demand is at the constant inflation level. Therefore nominal interest rates are the obvious instrument to use. Changing fiscal policy, on the other hand, creates distortions to the optimal public/private goods mix or to tax smoothing.

So the case against fiscal policy as the main stabilisation tool outwith the lower bound might go as follows: it is slower to change and it cannot be delegated. Even if monetary policy is not delegated politicians may allow popularity issues to get in the way of effective fiscal stabilisation. While government spending changes have a certain direct effect, they are also the most difficult to implement quickly.

A potentially strong argument against monetary policy is the lower bound problem. You could argue that having monetary policy as the designated stabilisation instrument gets government out of the habit of doing fiscal stabilisation, so that when you do hit the lower bound and fiscal stabilisation is essential it does not happen. Recent experience only confirms that concern. I personally do not think mainstream macroeconomists talk enough about this problem.

The fiscal rule that Jonathan Portes and I developed, a version of which is Labour's fiscal credibility rule, does attempt to address this very issue. Switching from monetary to fiscal at the lower bound is a key part of the rule. It is also worth stressing that this rule does not prevent temporary changes in fiscal policy to counteract a downturn outwith the lower bound. (Anyone who says otherwise does not understand the rule.) For example if interest rates are already low, a fiscal expansion that is planned to last less than five years is consistent with the rule, and might be a sensible precautionary measure. (Public investment, which is outside the rule, could also be used in this way.) So Labour’s fiscal rule allows monetary policy to do its job, but fiscal policy is always there as a back up if needed.



Tuesday, 9 January 2018

Why does economics get so much stick?

Because the advice of economists is so hopeless, you may say. Well think about the following thought experiment. After the financial crisis. suppose people had done the opposite of what the majority of economists said they should do. We do not need to imagine over Brexit, because most of the 52% who voted for Brexit chose to ignore, or more likely did not hear, the advice of 90+% of economists that Brexit would make them worse off. For those who work that belief was quickly shattered as their real wages fell as a direct result of Brexit.

Immediately after the financial crisis interest rates would not have been cut and austerity would have started in 2009, not 2010. Banks would have gone bust because economists said we needed to bail them out. In which case the Great Recession would have become the second Great Depression. Because the majority of economists did not support austerity you would have had continuing cuts in spending during this new depression.

So comparing this thought experiment with reality, we can see that economists have prevented a rerun of the 1930s depression, and if their majority advice had been taken we would have had a stronger recovery and the UK would not have left the EU. Sounds pretty good to me. But, as I’m sure you are now saying, what about the financial crisis the economists failed to warn of?

That was a mistake, but what are the consequences? Do you really think that if most economists had warned about how fragile the sector was anything would have happened? Banks would have continued to lend because they were making money and they had a guaranteed bail out from the state. Their campaign contributions would have weighed far more heavily in politicians’ minds than warnings from economists. So yes, not warning about the financial crisis was a mistake, but it would not have changed anything if the mistake had not happened. Economists are often told to stop being naive about politics, but the same needs to be said to their critics.

Despite such a strong record in macroeconomics since the crisis, why does economics get so much stick? I think there are three reasons. The first is simple: when the economy goes wrong, economists are easy to blame, particularly because of those forecasts that never predict downturns. In reality virtually no academic macroeconomists are involved in forecasting because they know that kind of unconditional forecasting is a mugs game [1], and furthermore most economists are not macroeconomists, but for some that kind of detail is irrelevant. (There are also plenty of highly successful pieces of microeconomics, but most critics act as if economics was just macroeconomics.)

The second reason is politics. Carlyle in 1849 called economics the dismal science because economists did not support his idea of reintroducing slavery. Ever since then economics has annoyed politicians and their supporters of various colours by pointing out the problems with various political programmes or schemes.

Politics is also at the heart of the third reason for criticism: politicians and ideologies of the right use the aspects of economics that suits their cause. Want to promote markets? Just take the idea from economics that an ideal market is an optimal way of exchanging goods, and ignore all the ways that real markets deviate from this ideal (ways which, incidentally, a great many economists spend a lot of their time studying). Some heterodox economists of the left, rather than use mainstream economics to point out how the right plays fast and loose with economic ideas, prefer to suggest that mainstream economics is much closer to the right wing caricature than it is in reality. It is why, as Noah Smith observes, so much of this criticism can be found in the pages of the Guardian.

This misrepresentation of mainstream economics is either deliberate or reflects ignorance. Ignorance about the fact that a lot of economics has become more empirical and therefore more eclectic in its use of theory over the last few decades, perhaps in part because of the influence of behavioural economics. Ignorance that even in macroeconomics, where ideological influences can be strong, there is more consensus around New Keynesian economics than some mainstream Keynesian economists imagine. (See my survey with André Moreira of post graduate teaching at the top schools here.) Nowadays you will find that in most areas of economics (alas not yet macro so much) there is nothing limiting the analysis to selfish individualistic behaviour. The idea that economics is like a religion is absurd.

But sometimes it is hard not to believe that popular criticisms of economics choose to ignore how far economics deviates from the neoliberal characterture. There is no excuse for ignoring that, for example, the best arguments against health care being left to the market can be found in a paper by Nobel prize winning economist Kenneth Arrow written decades ago. As the recent book by Colin Crouch suggests, the best critiques of neoliberalism come from within economics.

Another ridiculous charge against economics is that economics has a natural bias against state intervention. Indeed it is possible to argue the opposite. In my own field it is typical to assume the existence of a benevolent policy maker, who maximises social welfare. It is essentially just a useful analytical device, but you could argue if you wished to that this device biases those that use it to favour state intervention.

Judging by recent conversations I have had, many heterodox economists attack the mainstream because it uses the distinction between positive (value free) and normative economics. An example of positive economics would be me saying a temporary cut in government spending when interest rates are stuck at their lower bound reduces output. A normative statement would be that austerity is unfair. Heterodox economists like Sheila Dow seem to suggest that everything is value laden, and the positive/normative distinction allows economists to avoid being “morally implicated in the advice they give.”

I think this criticism is either trivial (yes, of course there may be normative reasons for choosing particular research topics) or dangerous. It is dangerous if it suggests that economists should be encouraged to base their analysis on assumptions that reflect their values. Economics, even though it is a social science, should conform to the scientific method: it should be as much like a science as medicine. Indeed I think it would greatly improve the public debate if both economists and their critics realised that economics, even though it is a unique and inexact science, is more like medicine than any of the hard sciences.

Dow writes “Getting policy-makers or the general public onside over a particular argument is therefore, critically, a matter of persuasion rather than demonstrable proof (since that proof is impossible).” But surely the best way of trying to persuade a policymaker not to impose austerity is to say that most models, including the consensus theoretical model, and nearly all the evidence suggests austerity will reduce output. In contrast it is far too easy to persuade a politician of things they want to hear. We do not want politicians to pick advice only if it is given by ‘one of us’ (by those who share their values), or as a result of the rhetorical skills of the academic.

The danger in encouraging plurality is that you make it much easier for politicians to select the advice they like, because there is almost certain to be a school of thought that gives the ‘right’ answers from the politicians point of view. The point is obvious once you make the comparison to medicine. Don’t like the idea of vaccination? Pick an expert from the anti-vaccination medical school. The lesson of the last seven years, in the UK in particular, is that we want mainstream economists to have more influence on politicians and the public, and not to dilute this influence through a plurality of schools of thought.

All this does not mean that economists are beyond criticism. As my last post pointed out, I have fundamental criticisms about current macroeconomic methodology. An important point to note about the microfoundations methodology is that it excludes economists who are not prepared to sign up to what is currently considered (by macroeconomists) acceptable microeconomics, or who do not think microfoundations is where you have to start in doing macro. But this critique has nothing to do with values. The mistake macroeconomics made in the 1980s was not in their desire to look for microfoundations, but in deciding that models that had internally consistent microfoundations were the only admissible models.

The big problem with most criticisms of economics you see in the media is not that economics is beyond criticism: as the paragraph above suggests it in many cases should be criticised, and there are plenty more interesting criticisms of economics available. The problem is that these more important criticisms are not those you find in the pages of the Guardian. The typical criticisms you see in the press are just not very good, and I fear reflect either ignorance or ideological antipathy.

[1] A lot of the criticisms of forecasters are themselves spurious. Someone who writes “economists should not need to pretend that we can predict things that do not really matter to several decimal places” are themselves pretending that there are any serious forecasters who do pretend this.

Thursday, 21 December 2017

Voting Labour isn’t going to turn the UK into Venezuela

but mainstream economists should make sure they are getting a hearing

It is tempting to laugh at the rhetoric of Conservative politicians or journalists when contemplating a possible future Labour government. As John Elledge writes, it isn’t long before Stalin or Trotsky or Venezuela is mentioned. As he notes, this is not a terribly clever tactic, particularly as many of the measures proposed by Labour are (by design) pretty popular. As Stephen Bush points out, the problem for the Conservatives is not that ‘young people’ have not learnt about the evils of communist regimes, but that this group are not impressed by Brexit or their wages and for many buying a house is something their parents generation did.

Yet this kind of hyperbole is not confined to politicians or journalists on the right. When John McDonnell, Labour’s shadow Chancellor, said at their party conference that they were ‘war-gaming’ for eventualities if they gained office like a run on sterling, I thought this showed mild paranoia. I was wrong. After I wrote that sterling was far more likely to rise at the prospect of a Labour government (standard macro: more fiscal, higher rates imply stronger currency), Buttonwood of the Economist wrote that there were at least five reasons why sterling might collapse, most of which involve some form of capital flight.

Although Buttonwood was careful to base analysis on measures that Labour proposed in 2017, I’m sure I was not imagining a subtext about what else could hard left politicians do. You can read much the same from some on the centre or soft left, who have learnt through experience to be wary of the hard left. Nick Cohen knows better than to call Labour’s new mass membership all militant entryists, but instead he says they are innocent (but should know better) lambs flocking towards wolves.

With language like this flying around, it is best to look for solid ground. In parliament Labour is a centre left party led by the hard left, to use popular labels. For that reason it would be impossible for it to pursue a hard left programme, and the leadership knows that. Contrast this with the current governing party: half soft, half hard right, with the latter having the upper hand because of the membership. The Conservative party’s ethos is such that the hard right have imposed a ruinous policy on our country without challenge, which actually did produce a collapse in sterling. Fortunately many Labour MPs have less loyalty and perhaps stronger principles, and would not allow anything similar if they were in power. As a result, I find pandering myths about Venezuela dishonest to be frank. If you want to fret about deselection, I suggest you talk to Nadine Dorries.

As far as City scare stories are concerned, as I indicated earlier and Ben Chu confirms, you will always be able to find those predicting doom. One of the refreshing things about this Labour leadership is that they do not cower defensively at such attacks, but come out fighting. As Corbyn’s video could have added, it was City economists who told us that austerity was necessary because otherwise there would be a flight from UK government debt. They were horribly wrong then, as interest rates on debt fell, and they are likely to be wrong again with new stories about capital flight under Corbyn.

While talk of Venezuela is ludicrous, there is a more interesting question about where the influences on future Labour policy are coming from. To set the scene, there was a recent prank outside the LSE designed to suggest heterodox economists were the Luther to economic mainstream Catholicism, and this was followed by a column from Larry Elliott in the Guardian. Now there are plenty of things to criticise about economics, but these are not them. As Frances Coppola recounts, the ‘economics reformation’ document is embarrassingly bad. If you want to read a short but to the point and well written response, see here.

So, in case you thought otherwise, mainstream economists do not spend their time attacking any form of market intervention, but instead try to design efficient market intervention. As I have argued many times, most mainstream macroeconomists did not endorse austerity, for the simple reason that textbooks and state of the art models suggest it would be a very bad idea. But there are some (not all) heterodox economists who would like you to believe otherwise.

What has this got to do with a future Labour government? Christine Berry presents a comprehensive account of who is shaping future Labour policy. It contains the following paragraph.
“John McDonnell’s Council of Economic Advisors, set up during the first days of the leadership, was a valiant effort to give the party’s economic policy some heavyweight academic backing. But many of its members were not natural Corbyn supporters, and ran alarmed from the public ridicule heaped on the leadership in the early days – resulting in the Council being largely disbanded. Academic input now seems to be ad hoc rather than systematised.”

That is not how it happened. It is true that some of us had to suffer some public ridicule when we joined, but that just reflected badly on those doing the ridiculing. The breakup of the Council was inevitable after the EU referendum. It is hard for any group of serious economists to publicly advise in such a forum any political party that appears to support a Brexit policy that is doing (see Chris Giles here) so much damage and could do much more.

The understandable wish of many heterodox economists to have an influence on Labour policy does mean there is a potential competition for influence. Will Labour policy be based on policies derived from mainstream analysis, or those favoured by some heterodox economists? It would be wrong to exaggerate this competition: most mainstream economists agree with most heterodox economists about austerity, for example. But there are some clear differences. (In some ways you see something similar on the right, where City economists compete with mainstream economists for influence on Conservative party policy, which is one reason Conservative macroeconomic policy can produce major disasters.)

Ann Pettifor has an article about why business would do well under Labour, which invokes some of the points made in an earlier Financial Times piece. Once you discount the scare stories, I agree with Ann that the economy and therefore businesses will do much better under Labour than under the Conservatives. But her article contains an interesting remark which I think tells us something about the current leadership. Ann’s says
“Here I must acknowledge a disagreement with Professor Simon Wren-Lewis, of Oxford University, who advised Labour to adopt a fiscal rule that once again prioritises monetary policy …”

Ann follows the heterodox MMT school that favours using fiscal rather than monetary policy to stabilise output and inflation. Of course both Ann and I were on Labour’s Economic Advisory Council, and so it is obvious that there was a similar discussion in this group.

The fact that McDonnell chose a more conventional but still innovative approach (which happened to be the one I put forward), and has also stressed the importance of central bank independence, shows us two things: he has a distinctly conservative streak, and he wants Labour not only to win but to be successful in economic terms. But while McDonnell may have opted for a mainstream approach on monetary and fiscal policy, there is still plenty to play for in other areas. I am not suggesting that mainstream economists should always win when conflicts occur, but it is important for mainstream economists not to arrive late to these battlefields, or worse still wait for politicians to read their papers.











Friday, 24 February 2017

The NAIRU: a response to critics

When I wrote my piece on NAIRU bashing, I mainly had in mind a few newspaper articles I had read which said we cannot reliably estimate it so why not junk the concept. What I had forgotten, however, is that for heterodox economists of a certain hue, the NAIRU is a trigger word, a bit like methodology is for mainstream economists. It conjures up lots of bad associations.

As a result, I got comments on my blog that were almost unbelievable. The most colourful was “NAIRU is the economic equivalent of "Muslim ban"”. At least two wanted to hold me directly responsible for any unemployment at the NAIRU. For example: “So according to you a fraction of the workforce needs to be kept unemployed.” Which is a bit like saying to doctors: “So according to you some people have to be allowed to die as a result of cancer.”

I have to say straight away that not everyone responded in that way. Some were much more thoughtful and constructive (like Jo Michell, for example). But the less thoughtful reactions are interesting in a way too.

I need to recap what the NAIRU is, particularly because heterodox economists seem to imagine it is many things it is not. Let’s take a very simple Phillips curve

Inflation this period = expected inflation next period - aU +b

where ‘a’ is a parameter and U is a measure of excess supply/demand in the economy. Unemployment will be one measure of that excess supply, but it is far from a perfect measure. (That my previous post was about excess supply, rather than actual unemployment, was obvious from what I wrote.) ‘b’ stands for a collection of slow moving variables. These could include a measure of union power, or how mobile labour was, or the degree of monopoly in the goods market. The NAIRU is defined as

NAIRU = b/a

If U is less than the NAIRU over a sustained period then inflation will rise, which will increase inflation expectations, which increases inflation further etc.

The concept is of interest to policymakers involved in demand management. They have to decide how much they can push demand before inflation starts rising. If they are independent central banks, they have to accept the world as it is. The NAIRU is a description of how the economy works: nothing more or less. This is why complaints that economists who use or estimate the concept are somehow responsible for those left unemployed are so dumb.

Of course you can criticise the concept of the NAIRU, but logically that has to involve criticism of the Phillips curve from where it comes. It is also reasonable to argue that the concept is fine, but the NAIRU is so difficult to measure that it would be better not to try and estimate it or let it guide policy. I have a lot of sympathy with that view at the moment, which is why I argue that, in the US right now, policy makers should find the NAIRU by allowing inflation to rise above target. But that point of view was irrelevant in my previous post, which was about the concept of the NAIRU, not its measurement.

As far as the concept is concerned, I think the strongest attacks come from thinking about hysteresis, as Jo Michell suggests. But even here, we add a complication to the NAIRU analysis, rather than overturn that analysis altogether. What hysteresis does is to make periods where unemployment is above the NAIRU extremely costly. It also means that periods of being slightly below the current NAIRU might be justified if they reduce the NAIRU itself.

I want to end by adding two reflections. The first relates to modelling the NAIRU. There once was, following the work of Layard and Nickell, an empirical literature that attempted to model for OECD countries a time series for the NAIRU, using proxy variables for things like union power, the benefit regime and geographical mismatch. With the dominance of the microfoundations methodology that work appears to have decreased, although to some extent it is still there in work based on matching models. I would be very interested to know if that time series analysis, now potentially enriched by matching models and flow data, has continued in any way.

The second relates to the sharp reactions to my original post I noted at the start, and the hostility displayed by some heterodox economists (I stress some) to the concept. I have been trying to decide what annoys me about this so much. I think it is this. The concept of the NAIRU, or equivalently the Phillips curve, is very basic to macroeconomics. It is hard to teach about inflation, unemployment and demand management without it. Those trying to set interest rates in independent central banks are, for the most part, doing what they can to find the optimal balance between inflation and unemployment.

Accepting the concept of the NAIRU does not mean you have to agree with their judgements. But if you want to argue that they could be doing something better, you need to use the language of macroeconomics. You can say, as many besides myself have done, that the NAIRU is either a lot lower than central bank estimates, or is currently so uncertain that these estimates should not influence policy. But if you say that the NAIRU has to be Bashed, Smashed, And Trashed, you will not get anywhere.

I also get very annoyed when I hear refutation by reference (as here for example). It would be so easy to write my blog posts that way. Instead I generally try to explain or present an argument that I hope is understandable. Economics is usually not so hard that this is impossible, although finding the right words is never easy. Economics is certainly not a religion, where all you have to do is choose which sect you belong to and then follow great works.     

Thursday, 3 November 2016

Ann Pettifor on mainstream economics

Ann has a article that talks about the underlying factor behind the Brexit vote. Her thesis, that it represents the discontent of those left behind by globalisation, has been put forward by others. Unlike Brad DeLong, I have few problems with seeing this as a contributing factor to Brexit, because it is backed up by evidence, but like Brad DeLong I doubt it generalises to other countries. Unfortunately her piece is spoilt by a final section that is a tirade against mainstream economists which goes way over the top. Let me just go through the factual errors.
“Economists dictated the terms for austerity that has so harmed the British economy and society over the past ten years.”

The only support she gives for this statement is the 20 economists who signed a letter to the Times on 14th February 2010. She neglects to mention that 58 equally notable economists signed a response in the Financial Times on 18th February arguing the 20 were wrong. Austerity has always been a minority view among academic economists, a minority that has got smaller over time. Of course those that signed the first letter, and in particular Ken Rogoff, turned out to be a more prominent voice in the subsequent debate, but that is because he supported what policymakers were doing. He was mostly useful rather than influential.
“As the policies have failed, the vast majority of economists have refused to concede wrongdoing, nor have societies been offered alternatives.“

In the case of the 20 economists who signed that letter, nearly half did revise their views just two years later. More importantly, for the last few years pretty well every macroeconomist of note, including Ken Rogoff, has advocated a substantial increase in public investment. So this sentence, in so far as it relates to austerity, is almost as wrong as it could be
“[On Brexit} All the heavyweights of the economics profession … were wheeled out to warn the British people of economic facts known, and understood apparently, only to ‘experts’... But the ‘experts’ and the economic stories they tell have been well and truly walloped by the result of this referendum. And rightly so, because while there is truth in the story that international and in particular European cooperation and coordination are vital to economic activity and stability, there is no sound basis to the widely espoused economic ‘religion’ that markets—in money, trade, and labour—must be unfettered, detached from democratic regulatory oversight, and must be left to ‘govern’ whole countries, regions, and continents.”

Where did these heavyweights talk about “economic facts known, and understood apparently, only to experts”? When they were given the chance, they explained the common sense idea that trade would suffer if we left the EU because it is easier to trade with your neighbours, and the easy to understand empirical findings that more trade increases productivity and therefore economic growth. There is no religion involved at all, but rather statistical evidence. If you are looking for religion, you need to focus on the handful of economists supporting Brexit, who really did believe that it could usher in a neoliberal nirvana that would more than offset the costs of Brexit. To the extent that the public ignored the warnings of economists, it was probably because these warnings were ‘balanced’ in the media by this handful.

When Ann talks about the failings of economists related to the financial crisis she has a point, but it is one that she grossly exaggerates. Economists hardly “led the way to the re-regulation and ‘liberalization’ of the finance sector over the past 40 years”. The way was led by the financial sector itself. If more economists had backed up rather than dismissed Rajan’s warnings in 2005, I doubt if anything would have changed. Why do I think this? Because mainstream economists have subsequently argued that the only way to prevent another crisis is to substantially increase the capitalisation of banks, but they have been completely ignored by policymakers. If economists are being ignored after the financial crisis which created untold damage, why should things have been any different before the crisis?

I think the same point applies to globalisation. Most economists have certainly encouraged the idea that globalisation would increase overall prosperity, and they have been proved right. It is also true that many of these economists did not admit or stress enough that there would be losers as a result of this process who needed compensating from the increase in aggregate prosperity. But once again I doubt very much that anything would have changed if they had. And if they didn’t think enough about it in the past, they are now: see Paul De Grauwe here for example.

There is a regrettable (but understandable) tendency by heterodox economists on the left to try and pretend that economics and neoliberalism are somehow inextricably entwined. The reality is that neoliberal advocates do use some economic ideas as justification, but they ignore others which go in the opposite direction. As I often point out, many more academic economists spend their time analysing market imperfections than trying to show markets always work on their own. They get Nobel prizes for this work. I find attempts to suggest that economics somehow helped create austerity particularly annoying, as I (and many others) have spent many blog posts showing that economic theory and evidence demonstrates that austerity was a huge mistake.         

Sunday, 4 September 2016

More on Stock-Flow Consistent models

This is a follow-up to this post, but which is prompted by this Bank of England paper, which builds a stock-flow consistent model for the UK. If you are not familiar with the term ‘stock-flow consistent’ (SFC) then read on, because in a sense this post is all about why I think the way the authors and others define this class of models is misleading.

SFC models are popular with Post-Keynesians, and the definition you find on Wikipedia is “a family of macroeconomic models based on a rigorous accounting framework, which guarantees a correct and comprehensive integration of all the flows and the stocks of an economy.” Now I suspect any mainstream macroeconomists would immediately respond that any DSGE model is also stock-flow consistent in this sense. This point is made in a post by Noah Smith, and it is completely valid, although otherwise I think his account of the weaknesses of SFC models is wide of the mark.

If you think this is a trivial debate about titles, take this description of the pros and cons of SFC compared to DSGE models taken from the paper:


Take the cons (merits of DSGE compared to SFC) first. Number one is almost definitional: DSGE models have to be microfounded, but SFC models start with aggregate relationships. But that is not a defining feature of SFC models, because there is a long tradition of macro modelling that is not microfounded but starts with aggregates, a tradition that begins well before DSGEs with the simultaneous creation of national accounts data, econometrics and Keynesian economics. This tradition goes by many names: ‘Structural Econometric Models’ (SEMs), ‘Cowles Commission’ (favoured by Ray Fair) or most recently ‘policy models’ (see Blanchard). I’ll just call them aggregate models here.
A key question, therefore, is what marks SFC models out from other aggregate models? The authors obviously think there is something, because of their second ‘con’. The third and fourth ‘cons’ are common to many large SEMs. (I once wrote a paper on how to mitigate the first of these problems.) The fifth ‘con’ just follows from the first.

At first sight the sixth ‘con’ does the same, but I would argue that if there is anything that characterises SFCs among aggregate models it is this. Aggregate models would generally involve an extensive discussion of the theoretical origins of the relationships they used, but if this paper is anything to go by that is less true for SFCs. If you think this last point is unfair, look at the discussion of the consumption function (before equation 4).

This failure to acknowledge the existence of other aggregate models is even more apparent among the ‘pros’. The first and second can be true for any model, including a DSGE model, but the third is critical. It is true, but again it is also true for many aggregate and some DSGE models. As I argue in my previous post, the key point about the archetypal DSGE model is that it does not need to track household wealth, because there is no attempt by consumers (given the theory) to achieve some target value of wealth.

The fourth is true for any model, including DSGE models. The fifth is true for any aggregate model as long as expections variables are explicitly identified. The sixth is also almost bound to be true of any aggregate model, because starting with aggregates and being eclectic (and potentially internally inconsistent) with theory allows you to more closely match the data than DSGEs.

To summarise, if you were to ask how this model compares to other aggregate (non-microfounded) models, the answer would probably be that it takes theory less seriously and it has a rather elaborate financial side.

The New Classical counter revolution had many good and bad consequences, but one of the undesirable consequences was, it seems, to define the equivalent of a year zero in macroeconomics, where nothing that was not in the New Classical tradition created before (or even after) this revolution is deemed to exist. The same should not be true for heterodox economists. If you are going to effectively return to a pre-DSGE tradition, please do not pretend that tradition did not exist.

There is a well known UK professor of econometrics who was very fond of admonishing authors who failed to cite work that they were either extending or just copying. The intention here is not just to do the same. One of the big dangers with any kind of elaborate aggregate model is that you can get bizarre model properties from not thinking enough about the theory, or imposing enough because of the theory. Knowing some of the authors I doubt that has happened in this case. But it would be a mistake for others to believe that the properties of their model show the importance of accounting rather than the theory they have used.