Talk on where macroeconomics went wrong

I gave a short talk yesterday with this title, which takes some of the main points from my paper in the  OXREP 'Rebuilding Macro' volume  It is mainly of interest to economists, or those interested in economic methodology or the history of macroeconomic thought. When I talk about macroeconomics and macroeconomists below I mean mainstream academic economists.  

I want to talk today about where macroeconomics went wrong. Now it seems that this is a topic where everyone has a view. But most of those views have a common theme, and that is a dislike of DSGE models. Yet DSGE models are firmly entrenched in academic macroeconomics, and in pretty well every economist that has done a PhD, which is why the Bank of England’s core model is DSGE. To understand why DSGE is so entrenched, I need to tell the story of the New Classical Counter Revolution (NCCR).

If you had to pick a paper that epitomised the NCCR it would be “After Keynesian Macroeconomics” by Lucas and Sargent. Now from the title you would think this was an attack on Keynesian Economics, and in part it was. But we know that revolution failed. Very soon after the NCCR we had the birth of New Keynesian economics that recast key aspects of Keynesian economics within a microfoundations [1] framework, and is now the way nearly all central banks think about stabilisation policy. But if you read the text of Lucas and Sargent it is mainly a manifesto about how to do macroeconomics, or what I think we can reasonably call the methodology of macroeconomics.And on that their revolution was successful, and it is why nearly all academic macro is DSGE.

Before Lucas and Sargent complete macroeconomic models, of both a theoretical and empirical kind, had justified their aggregate equation using an eclectic mix of theory and econometrics. Microfoundations were used as a guide to aggregate equation specification, but if this equation fell apart in statistical terms when confronted with data in would not become part of an empirical model, and would be shunned for inclusion in theoretical models. Off course ‘falling apart ‘ is a very subjective criteria, and every effort would be made to try and make an equation consistent with microfoundations, but typically a lot of the dynamics in these models were what we would now call ad hoc, which in this case meant data based. .

Lucas famously showed that models of this kind were subject to what we call the Lucas critique [2], and that forms an important part of Lucas and Sargent paper. They argue that the only certain way to get round that critique is to build the model from internally consistent microfoundations. But they also ask why wouldn’t you want to build any macroeconomic model that way? Why wouldn’t you want a model where you could be sure that aggregate outcomes were the result of agents behaving in a consistent manner

If you want to crystallise why this was a methodological revolution, think about what we might call admissibility criteria for macro models. In pre-NCCR models equations were selected through an eclectic mixture of theory-fit and evidence-fit. In the RBC and later DSGE models internal theoretical consistency is an admissibility criteria. Or to put it another way, a DSGE model never got rejected because one of its equations didn’t fit the data, but if one equation had a theoretical foundation that was inconsistent with the others it would certainly not be published in the better journals.

Have a look at almost any macro paper in a top journal today, and compare it to a similar paper before the NCCR, and you can see we have been through a methodological revolution. Unfortunately many economists who have only been taught and who only known DSGE just think of this as progress. But it is not just progress, because DSGE models involve a shift away from the data. This is inevitable if you change the admissibility criteria away from the data. It inevitably means macroeconomists start focusing on models where it is easy to ensure internal theoretical consistency, and away from macroeconomic phenomenon that are clear in the data but more difficult to microfound.

If you are expecting me at this point to say that DSGE models where were macroeconomics went wrong, you will be disappointed. I spent the last 15 years of my research career building and analysing DSGE models, and I learnt a lot as a result. The mistake was the revolution part. In the US, DSGE models replaced traditional modelling within almost a decade [3]. In my view DSGE models should have coexisted with more traditional modelling, each tolerating the other.

To get a glimpse of how that can happen look at the UK, where a traditional macromodelling scene remained active until the end of the millenium. Traditional models didn’t stand sill, but changed by adopting many of the ideas from DSGE such as rational expectations. Here the account gets a little personal, because before I did DSGE I built one of those models, called COMPACT. There are not many macroeconomists who have built and operated both traditional and DSGE models, which I think gives me some insight of the merits of both.

COMPACT was a rational expectations New Keynesian model with explicit credit constraints in a Blanchard-Yaari type consumption function, a vintage production model, and variety effects on trade. So in terms of theoretical ideas it was far richer than any DSGE model I subsequently worked with. Most of COMPACT’s behavioural equations were econometrically estimated, but it was not an internally consistent model like DSGE.

COMPACT had an explicit but exogenous credit constraint variable in the model because in our view it was impossible to model consumption behaviour over time without it. Our work was based heavily on work in the UK by John Muellbauer, and Chris Carroll was coming to similar conclusions for the US. But DSGE models never faced that issue because they worked with de-trended data. Let me spell out why that was important. Empirical work was establishing that you could not begin to understand consumption behaviour over a 20/30 year time horizon without seeing how the financial sector had changed over time, and at least one traditional macroeconomic model was incorporating that finding before the end of the last millennium.. Extensive work on exactly that issue did not begin using DSGE models until after the financial crisis, where changes in the financial sector had a critical impact on the real economy. DSGE was behind the curve, but more traditional macroeconomics was not. .

Now I don’t think it is fanciful to think that if at least some macroeconomists had continued working with more traditional data-based models alongside those doing DSGE, at least one of those models would have thought to endogenise the financial sector which was determining those varying credit constraints.

So the claim I want to make is rather a big one. If DSGE models had continued alongside more traditional, data-based modelling, economists would have been much better prepared for the financial crisis when it came. If these two methodologies had learnt from each other, DSGE models might have started focusing on the financial sector before the crisis. Of course I would never suggest that macroeconomics could have predicted that crisis, but macroeconomists would have certainly had much more useful things to say about the impact on the economy when it happened.

Just being able to imagine this being true illustrates that moving to DSGE involved losses as well as gains. It inevitably made models less rich and moved them further away from the data in areas that were difficult but not impossible to model in a theoretically consistent way. The DSGE methodological revolution set out so clearly in Lucas and Sargent's paper changed the focus of macroeconomics away from things we now know were of critical importance.

I’ve been talking about this since I started writing a blog at the end of 2011, but recently we have seen similar messages from Paul Romer and Olivier Blanchard in this OxREP volume. What I have called here traditional models, and in the paper I call Structural Econometric Models, Blanchard calls provocatively policy models. It was provocative because most academic macroeconomists think DSGE models are the only models that can do policy analysis ‘properly’, but Blanchard suggests policymakers want models that are closer to the data more than they want a guarantee of internal consistency, and they want models that are quick and easy to adapt to unfolding problems. The US Fed, although it has a DSGE model, also has a more traditional model that has similarities to a traditional model like COMPACT, and guess which model plays the major role in the policy process?

[1] Microfoundations means deriving aggregate equations from microeconomic optimisation behaviour

[2] The Lucas critique argued that many equations of traditional macroeconomic models embodied beliefs about macro policy, and so if policy changed the equations would no longer be valid.

[3] The difficulty of identification in single equation estimation highlighted by Sims in 1980 probably also contributed.  . 

Why the microfoundations hegemony holds back macroeconomic progress

When David Vines asked me to contribute to a OXREP (Oxford Review of Economic Policy) issue on “Rebuilding Macroeconomic Theory”, I think what he hoped I would write on how the core macro model needed to change to reflect macro developments since the crisis with a particular eye to modelling the impact of fiscal policy. That would be an interesting paper to write, but I decided fairly quickly that I wanted to say something that I thought was much more important.

In my view the biggest obstacle to the advance of macroeconomics is the hegemony of microfoundations. I wanted at least one of the papers in the collection to question this hegemony. It turned out that I was not alone, and a few papers did the same. I was particularly encouraged when Olivier Blanchard, in blog posts reflecting his thoughts before writing his contribution, was thinking along the same lines.

I will talk about the other papers when more people have had a chance to read them. Here I will focus on my own contribution. I have been pushing a similar line in blog posts for some time, and that experience suggests to me that most macroeconomists working within the hegemony have a simple mental block when they think about alternative modelling approaches. Let me see if I can break that block here.

Imagine a DSGE model, ‘estimated’ by Baynesian techniques. To be specific, suppose it contains a standard intertemporal consumption function. Now suppose someone adds a term into the model, say unemployment into the consumption function, and thereby significantly improves the fit of the model. It is not hard to think why the fit significantly improves: unemployment could be a proxy for the uncertainty of labour income, for example. The key question becomes which is the better model with which to examine macroeconomic policy: the DSGE or the augmented model?

A microfoundations macroeconomist will tend to say without doubt the original DSGE model, because only that model is known to be theoretically consistent. (They might instead say that only that model satisfies the Lucas critique, but internal consistency is the more general concept.) But an equally valid response is to say that the original DSGE model will give incorrect policy responses because it misses an important link between unemployment and consumption, and so the augmented model is preferred.

There is absolutely nothing that says that internal consistency is more important than (relative) misspecification. In my experience, when confronted with this fact, some DSGE modellers resort to two diversionary tactics. The first, which is to say that all models are misspecified, is not worthy of discussion. The second is that neither model is satisfactory, and research is needed to incorporate the unemployment effect in a consistent way.

I have no problem with that response in itself, and for that reason I have no problem with the microfoundations project as one way to do macroeconomic modelling. But in this particular context it is a dodge. There will never be, at least in my lifetime, a DSGE model that cannot be improved by adding plausible but potentially inconsistent effects like unemployment influencing consumption. Which means that, if you think models that are significantly better at fitting the data are to be preferred to the DSGE models from whence they came, then these augmented models will always beat the DSGE model as a way of modelling policy.

What this question tells you is that there is an alternative methodology for building macroeconomic models that is not inferior to the microfoundations approach. This starts with some theoretical specification, which could be a DSGE model as in the example, and then extends it in ways that are theoretically plausible and which also significantly improve the model’s fit, but which are not formally derived from micofoundations. I call that an example within the Structural Econometric Model (SEM) class, and Blanchard calls it a Policy Model.

An important point I make in my paper is that these are not competing methodologies, but instead they are complementary. SEMs as I describe them here start from microfounded theory. (Of course SEMs can also start from non-microfounded theory, but the pros and cons of that is a different debate I want to avoid here.) As a finished product they provide many research agendas for microfoundation modelling. So DSGE modelling can provide the starting point for builders of SEMs or Policy Models, and these models when completed provide a research agenda for DSGE modellers.

Once you see this complementarity, you can see why I think macroeconomics would develop much more rapidly if academics were involved in building SEMs as well as building DSGE models. The mistake the New Classical Counter Revolution made was to dismiss previous ways of modelling the economy, instead of augmenting these ways with additional approaches. Each methodology on its own will develop much more slowly than the two combined. Another way of putting it is that research based on SEMs is more efficient than the puzzle resolution approach used today. 

In the paper, I try to imagine what would have happened if the microfoundations project had just augmented the macroeconomics of the time (which was SEM modelling), rather than dismissing it out of hand. I think we have good evidence that active complementarity between SEM and microfoundations modelling would have investigated in depth links between the financial and real sectors before the financial crisis. The microfoundations hegemony chose the wrong puzzles to look at, deflecting macroeconomics from the more important empirical issues. The same thing may happen again if the microfoundations hegemony continues.

It’s the economics, not the politics

A reflection on rereading an old paper

Regular readers will have noticed that I’m not a great fan of the current government’s economic policies, or its Chancellor (with the very important exception of setting up the OBR). Some will assume that this reflects a political bias - indeed those who are political animals often cannot conceive that everything is not politically driven. If you are looking for evidence either way, this post is about that.

Yesterday I received an email advertising ‘The Economics of Austerity’, which is a collection of essays published by Edward Elgar and chosen by Suzanne Konzelmann. There are 47 in all, but as this includes pieces by Hume, Smith, Ricardo and Mill, you can see that this collection aims to give a historical perspective on the subject. To be honest the email might have got lost in my in-tray if I hadn’t noticed it started ‘Dear Contributor’. Sure enough, in the eight essays dealing with the period after the financial crisis, there was my name alongside others, including some guy named Krugman.

I should have been flattered, but instead my heart sank. The selected paper was originally published in OXREP in 2010, and I remember it now as being hopelessly optimistic. It was written before the Euro crisis, so before austerity became almost universal. Little over a year later I wrote a paper with the title ‘Lessons from failure: fiscal policy, indulgence and ideology’, which seems much more appropriate in the current environment. Yet I thought I ought to reread my OXREP article, to confirm just how dated it had become.

Actually it really is not that bad. The key points are still things I believe. The financial crisis was primarily a crisis involving financial regulation rather than monetary policy or global imbalances. The idea that the Great Moderation was due to improved monetary policy was sound, but it always came with a caveat involving large negative shocks, because of the zero lower bound (ZLB). The ZLB could be mitigated using what I now call a ‘forward commitment’ to higher future inflation, but time inconsistency would make central banks reluctant to pursue that. The obvious alternative was expansionary fiscal policy. If concerns over debt where a constraint, then an effective measure was balanced budget increases in government spending.

This last point is so important, yet it can get lost in the debate. If you want to plug a demand gap at the ZLB, temporary increases in government spending financed by temporary increases in taxes work, because a lot of the tax increase comes out of saving rather than consumption. As the tax increase is temporary and only happens while there is widespread unemployment, concerns about the incentive effects of higher taxes on labour supply are at worst irrelevant. This is basic macroeconomics. But then I wrote this:

“The main problem with fiscal measures to expand the economy which do not raise debt is political. Higher government spending, even if it is temporary, raises taxes and temporarily increases the size of the state, which is unpopular on the right of the political spectrum. Fiscal transfers that move money from unconstrained savers to those who are credit constrained also tend to involve transfers from the rich to the poor. Although useful from the point of view of stimulating effective demand, they may not be politically acceptable.”

Quite. What was missing was an equivalent paragraph saying that, even if there was no economic problem with raising debt, debt financed fiscal expansion might be resisted for political reasons. However, I now want to return to where I started. The OXREP paper was written before the current coalition was elected. It set out how I saw the macroeconomics. At the ZLB you could use unconventional monetary policy, but in addition you should use fiscal stimulus, whether debt was a constraint or not.

It was politics - and ideology - that got in the way of good macroeconomics, which is why the UK and global recession has been so prolonged. And it is that tendency that is personified by George Osborne. Even if debt was erroneously thought to be a constraint, we should have had tax financed increases in public investment rather than cuts. This extra investment could have been on politically neutral things, like flood defences.

Unfortunately austerity turns out to be part of a pattern. There is another example from the OXREP paper. When talking about an environment of low real interest rates, I noted the danger of housing bubbles, but also how specific fiscal instruments could be effective (relative to raising interest rates) in dampening these bubbles. A corollary, of course, is that these same instruments used in reverse can be used to make bubbles much worse, or indeed to initiate them, as in Help to Buy. House prices are now above their previous 2008 (bubble?) peak. Maybe this is good politics, but it is lousy economics.

So I do not think the complaint of political bias stands up. What you could perhaps argue is that I’m being politically naive: that all Chancellors maximise political advantage at the expense of national economic interest. The fact that Gordon Brown’s scorecard seems much better (including resisting Blair to stay out of the Euro) could just reflect opportunities and circumstances rather than anything else. It is certainly true that the position George Osborne inherited, as a result of the financial crash, was much more difficult than Brown’s inheritance. But go back to the time I wrote the OXREP article. At the end of 2008 Labour did undertake fiscal expansion, and it was opposed by Cameron and Osborne. As I noted here, Osborne in April 2009 argued that monetary policy should “bear the strain of stimulating demand”, seemingly oblivious to interest rates being as low as they could go. So Labour’s policy was consistent with the arguments in my OXREP article (which in turn reflected basic macroeconomics), while Conservative policy just ignored them. 

So thank you Dr. Konzelmann, for including me in such good company. But also thank you for making me reread the paper and revise my memory of it. [1]

[1] I fear I cannot also thank the publishers, who tell me that unfortunately I cannot have a complimentary copy, because of the large number of contributors. I’ll leave it to Hume, Smith, Ricardo and Mill to complain directly. I guess Keynes, who has 5 essays in the book, probably got a copy!

The last Labour Government: has the influence of economists ever been greater?

The latest issue [1] of the Oxford Review of Economic Policy is devoted to an analysis of the record of the last Labour government (1997-2010). My own contribution is on fiscal policy, but I do not want to talk about that here, as I already have a post covering the main points. Instead I want to reflect just a little on Labour’s entire economic record. One way of characterising this period, which those outside the UK may not be fully aware of, is that it was a government in which the influence of mainstream economics has never been greater.

One of the government’s first acts was to give independence to the Bank of England, under a regime of inflation targeting. Not only was this straight out of the mainstream macro playbook, but its design included elements of transparency and accountability that led economists at the time to label it best practice. (1997 also saw the appointment as deputy governor of the Bank of England of Mervyn King, who in many ways is the central banker mainstream economics might wish for.) In my paper I argue that the fiscal rules that came shortly afterwards were much closer to mainstream academic views than either what had gone before, or what subsequently happened in Europe. Even when those rules broke down after the recession, the instinct to use fiscal policy in a countercyclical way was entirely mainstream. Not to be forgotten is the decision in 2003 not to become part of the Eurozone, which could well have gone the other way if political factors had played a larger role.  

In terms of microeconomic policy, the ethos was generally ‘light touch’ regulation, but with intervention where there was perceived to be a clear market imperfection. There was a particular interest in improving productivity (where the UK had traditionally performed badly in terms of international comparisons), but the interventions were of the kind economists would generally recommend (improving human capital, enhancing competition policies, subsidising R&D), rather than any attempt to pick winners. There was a clear aim to reduce poverty, but again this was done through the tax and benefit system, rather than trying to directly influence market outcomes. (An exception was the introduction of the minimum wage, but that had a lot of support among mainstream economists.) In the public sector there was a continuing trend towards introducing incentives and market processes. There was a deliberate lack of concern about inequality at the top. Now of course not all mainstream economists would endorse all these developments, but I don’t think a newly graduating student of economics would be puzzled by much of this. And of course the fact that these policies reflected mainstream economics did not make them right, as we all found out during the financial crisis.

Why was mainstream economics so powerful? I speculate a bit below, but for this particular administration it may have been in part a political accident - the deal struck between Gordon Brown and Tony Blair, where Blair got to be Prime Minister, but Brown’s Treasury became more powerful than it has perhaps ever been. Of course that does not tell us why Brown himself was so influenced by mainstream economics (his PhD was in history).

So how successful was this ‘government by economists’? As the editors (David Cobham, Christopher Adam, and Ken Mayhew) in their introduction note, if the government had ended in 2007 the verdict would have included many pluses. Over the previous decade the macroeconomy was remarkably stable. Unemployment continued to fall. Although fiscal policy had it failings, the rules had been kept, the budget deficit was not far from a sustainable level and debt to GDP was lower than a decade earlier. The health service clearly got better. As Van Reenan documents, UK productivity continued to improve relative to other countries, and he suggests this cannot be dismissed as just a hangover from the reforms of the previous Conservative government. (See also this CEP paper coauthored with Corry and Valero.) The achilles heel was of course the light touch regulation of the financial markets (discussed in a nice paper by Arup Daripa, Sandeep Kapur, and Stephen Wright). However this too can be seen as a failure of mainstream economics as much as a political error.

It is interesting to speculate whether any government could have avoided having its reputation defined by what happened in 2008. Perhaps it could have: given the recession, the election result in 2010 was surprisingly close. However, once a new government took over, we had the familiar story of the victor rewriting history. To quote from the introduction (but my emphasis), the new Coalition government claimed  

“… that the principal legacy of the 1997–2010 Labour government was an economic policy framework that was both in (large) measure responsible for the financial crisis of 2008 and also unable to address its consequences. As we hope the papers in this issue of the Oxford Review illustrate, this charge cannot be made to stick, and the period of the Labour government was much more interesting and more important for the long-run prospects of the UK economy than this simple ‘external’ narrative suggests.”

I completely agree, but then as an economist perhaps I’m biased.

The last few years have been a painful reminder that there is nothing inevitable about this rising influence of mainstream economics in the UK (or elsewhere? - I would be fascinated by the thoughts of others in other countries.) While it is tempting to link this influence to the colour of the party in power, I would hardly call policies adopted by the Labour governments of the 1970s as reflecting the mainstream economics of the time (e.g. attempts to control inflation through prices and incomes policies). Perhaps a better interpretation is that mainstream economics (which should be neither slavishly pro or anti market) has its greatest influence on less ideological governments of the center, and its just that since the 1980s the traditional political left has been out of the equation. Whatever the linkage, I wonder how long it will be before we again see a UK government so influenced by mainstream economics.

[1] If anyone is reading this late, its the Spring 2013 issue