Winner of the New Statesman SPERI Prize in Political Economy 2016

Saturday, 24 September 2016

What is so bad about the RBC model?

This post has its genesis in a short twitter exchange storified by Brad DeLong

DSGE models, the models that mainstream macroeconomists use to model the business cycle, are built on the foundations of the Real Business Cycle (RBC) model. We (almost) all know that the RBC project failed. So how can anything built on these foundations be acceptable? As Donald Trump might say, what is going on here?

The basic RBC model contains a production function relating output to capital (owned by individuals) and labour plus a stochastic element representing technical progress, an identity relating investment and capital, a national income identity giving output as the sum of consumption and investment, marginal productivity conditions (from profit maximisation by perfectly competitive representative firms) giving the real wage and real interest rate, and the representative consumer’s optimisation problem for consumption, labour supply and capital. (See here, for example.)

What is the really big problem with this model? Not problems along the lines of ‘I would want to add this’, but more problems like I would not even start from here. Let’s ignore capital, because in the bare bones New Keynesian model capital does not appear. If you were to say giving primacy to shocks to technical progress I would agree that is a big problem: all the behavioural equations should contain stochastic elements which can also shock this economy, but New Keynesian models do this to varying degrees. If you were to say the assumption of labour market clearing I would also agree that is a big problem.

However none of the above is the biggest problem in my view. The biggest problem is the assumption of continuous goods market clearing aka fully flexible prices. That is the assumption that tells you monetary policy has no impact on real variables. Now an RBC modeller might say in response how do you know that? Surely it makes sense to see whether a model that does assume price flexibility could generate something like business cycles?

The answer to that question is no, it does not. It does not because we know it cannot for a simple reason: unemployment in recessions is involuntary, and this model cannot generate involuntary unemployment, but only voluntary variations in labour supply as a result of short term movements in the real wage. Once you accept that higher unemployment in recessions is involuntary (and the evidence for that is very strong), the RBC project was never going to work.

So how did RBC models ever get off the ground? Because the New Classical revolution said everything we knew before that revolution should be discounted because it did not use the right methodology. And also because the right methodology - the microfoundations methodology - allowed the researcher to select what evidence (micro or macro) was admissible. That, in turn, is why the microfoundations methodology has to be central to any critique of modern macro. Why RBC modellers chose to dismiss the evidence on involuntary unemployment I will leave as an exercise for the reader.

The New Keynesian (NK) model, although it may have just added one equation to the RBC model, did something which corrected its central failure: the failure to acknowledge the pre-revolution wisdom about what causes business cycles and what you had to do to combat them. In that sense its break from its RBC heritage was profound. Is New Keynesian analysis still hampered by its RBC parentage? The answer is complex (see here), but can be summarised as no and yes. But once again, I would argue that what holds back modern macro much more is its reliance on its particular methodology.

One final point. Many people outside mainstream macro feel happy to describe DSGE modelling as a degenerative research strategy. I think that is a very difficult claim to substantiate, and is hardly going to convince mainstream macroeconomists. The claim I want to make is much weaker, and that is that there is no good reason why microfoundations modelling should be the only research strategy employed by academic economists. I challenge anyone to argue against my claim.




Friday, 23 September 2016

Inequality under the Labour government

In the last few months I have sometimes been told that the last Labour government did nothing to reverse the rise of inequality seen under the previous Conservative administration. It is a serious charge, given the harm that inequality creates. But it is also incorrect, and here is a nice chart that shows why.


The Gini coefficient measures inequality. The black line looks at incomes, but the grey line looks at full time earnings. It shows that inequality in earnings was rising throughout the period, including when Labour was in power. Inequality of incomes was flatter while Labour was in power.

The chart is taken from a paper by Mike Brewer and Liam Wren-Lewis (short summary here). The authors use microdata to explain these divergent trends in the 1990s and 2000s. They find four factors at work.
“First, inequality between those with different employment statuses has fallen, primarily due to a fall in the number of unemployed. Second, employment taxes have played a larger role since 1991 in mitigating the increase in inequality of gross employment income than they did before 1991. Third, investment income has contributed less to total income inequality since 1991, largely due to the decline in its importance as an income source. Finally, a rise in the relative incomes of pensioners and households with children under five – both groups that benefited from reforms to welfare benefits and tax credits during the 1990s and (especially) 2000s – has pulled inequality down. Overall, since 1991 these four factors have almost entirely offset the impact on income inequality of the inequality-increasing changes in the distribution of earnings and self-employment income.”

Some of these factors may not have owed much to government policy, but others clearly did. The bottom line is that the last Labour government did quite a lot to reduce inequality. Only once you recognise that can you be realistic about what it would take to do more. Here are some ideas from Tony Atkinson, and I personally would be even more radical in one particular area. 

Thursday, 22 September 2016

Explaining macroeconomics to the Swabian housewife

Matthew Bishop has a nice simple post at SPERI suggesting how the ‘economy is like a household’ idea can be tackled. He is correct that this analogy has tremendous power, to the extent that I doubt we would have seen so much UK austerity without it. He uses an exchange between Yanis Varoufakis and a member of the Question Time audience to suggest that attempts to simply explain the economics are ineffective. He suggests that the “problem, as Jonathan Hopkin and Ben Rosamond have suggested (here and here), is that you cannot fight ‘political bullshit’ with facts”.

I want to make some observations, in ascending order of importance.
  1. I think he is right that economists can usefully point out that households do not always balance their budgets. But all the examples he gives help explain why it may make sense for the government to borrow to invest. Indeed he could have added comparisons between governments and firms in this respect. That is why it is easy for economists to now argue that governments should be borrowing more to invest. I’m sure most economists would use exactly these analogies: after all most do try to teach this stuff.

  2. However these analogies do little for the issue the audience member thought we were dealing with. He thought the analogy was exactly the case of spending too much on excessive drinking, and needing to sober up financially. While the examples Matthew quotes get you over the simplistic idea that governments should never borrow, they do not explain why (a) it is OK in principle to keep the ratio of government debt to GDP constant (governments live forever), and (b) why it makes sense for governments to borrow a lot more in a recession (the automatic stabilisers), or even (c) why the government should go out of its way to borrow even more in a recession when interest rates are at the Zero Lower Bound. We can try and get these ideas across as simply as we can, as I have tried many times (and suggestions on how to do it better are always welcome), but it is very difficult to do so in a minute or two on Question Time. It is sufficiently difficult that before the General Theory it was not understood by most economists.

  3. I think the suggestion that economists are too busy trying to be correct and therefore too scornful of simple analogies is a little unfair. Only a little: in a live public appearance there is always the concern about what your colleagues in the department will say afterwards. Economists are also aware, as Chris Dillow points out, that partial analogies used in one context can easily backfire in others. However I doubt very much that most economists do the equivalent of mocking “every grammatical error made by friends practising their holiday Spanish”.

  4. The big difference between economists and scientists at CERN is not that economists are less respectful of lay people’s mistakes. It is (a) they have politicians repeating false analogies about their subject as if they were facts, and (b) large sections of the print media doing the same, and (c) most of the rest of the media too clueless to challenge these falsehoods.

  5. This is why, for an evidence based discipline like economics, the response ‘economists know that the economy is not like a household in important respects and here is why’ is not at the end of the day arrogant or dismissive. If Brian Cox was asked on Question Time ‘what is all this about the Earth moving: it is obvious that everything moves around the Earth’ we would not blink an eyelid if he replied ‘No, scientists know that is not true and it only seems that way to you because..’.

  6. What austerity tells us, just as the climate change denial tells us, is that in today’s world respect for science is fragile. In the US public opinion about climate change is sharply divided along political lines, despite the near unanimity among scientists. It is this that should really worry us, and not how climate change scientists can better communicate with the public, desirable though that might be in itself. A world where the scientist has to compete on equal terms with the ignorant polemicist is not a healthy world.



Wednesday, 21 September 2016

The Treasury and Brexit

I pointed out two days ago that the real costs of Brexit are long term, which unfortunately means that those who argued for Brexit will never be held responsible in political terms for the damage it will do. As John Springford argues, that also strengthens the hand of those arguing for a hard Brexit (aka maximum damage). So who will speak for the 48%+ who want to limit the damage?

Potentially the majority of MPs do. We have united opposition from the SNP and LibDems. The great majority of Labour MPs also oppose Brexit. Polly Toynbee suggests this should become their unifying cause whatever the leadership does. And of course around half of Conservative MPs probably voted, in a personal capacity, to Remain. That has to be a worry for Theresa May, which is why she has made it clear that MPs will have no effective say in the Brexit negotiations.

So is this just going to amount to a lot of despairing and angry complaints as the Brexiters do their worst. Not quite. There is one source of opposition left standing (in the sense of having some power): Philip Hammond and H.M.Treasury. The Treasury has always been the job Hammond wanted, and not because he wanted to radically change that institution. It should also not be forgotten that it was Treasury economists who wrote the analysis suggesting the long run impact of Brexit on the UK economy could be very large, and the larger the further away from the single market we ended up being. Some will think this was a stitch-up job to please Osborne, but I think that is extremely unlikely. After all the Treasury analysis was pretty close to other estimates, and it was overseen by Charlie Bean who is excellent at judging what is academically kosher.

It is for this reason that we are already seeing headlines talking about Hammond blocking Brexit ‘progress’. How much power he has to do this will depend on the Prime Minister. If Theresa May sides with her Brexit ministers against Hammond, as it seems increasingly likely (see Martin Wolf here), this will mark the end of a long period where the Treasury has dominated economic policy in the UK.

That dominance started after a meeting in an Islington restaurant, where Gordon Brown extracted the maximum price for standing aside in favour of Tony Blair. The Treasury under Brown not only stopped Tony Blair from adopting the Euro, but also exerted a control over the economic aspects of other departments that had not been seen before. Under the Coalition government Osborne and Cameron worked very closely together, and the austerity strategy - supported by key Treasury civil servants - dominated the domestic agenda. If May sidelines Hammond over Brexit, the Treasury will have moved from dominance to playing second fiddle very quickly indeed.



Tuesday, 20 September 2016

Paul Romer on macroeconomics

It is a great irony that the microfoundations project, which was meant to make macro just another application of microeconomics, has left macroeconomics with very few friends among other economists. The latest broadside comes from Paul Romer. Yes it is unfair, and yes it is wide of the mark in places, but it will not be ignored by those outside mainstream macro. This is partly because he discusses issues on which modern macro is extremely vulnerable.

The first is its treatment of data. Paul’s discussion of identification illustrates how macroeconomics needs to use all the hard information it can get to parameterise its models. Yet microfounded models, the only models deemed acceptable in top journals for both theoretical and empirical analysis, are normally rather selective about the data they focus on. Both micro and macro evidence is either ignored because it is inconvenient, or put on a to do list for further research. This is an inevitable result of making internal consistency an admissibility criteria for publishable work.

The second vulnerability is a conservatism which also arises from this methodology. The microfoundations criteria taken in its strict form makes it intractable to model some processes: for example modelling sticky prices where actual menu costs are a deep parameter. Instead DSGE modelling uses tricks, like Calvo contracts. But who decides whether these tricks amount to acceptable microfoundations or are instead ad hoc or implausible? The answer depends a lot on conventions among macroeconomists, and like all conventions these move slowly. Again this is a problem generated by the microfoundations methodology.

Paul’s discussion of real effects from monetary policy, and the insistence on productivity shocks as business cycle drivers, is pretty dated. (And, as a result, it completely misleads Paul Mason here.) Yet it took a long time for RBC models to be replaced by New Keynesian models, and you will still see RBC models around. Elements of the New Classical counter revolution of the 1980s still persist in some places. It was only a few years ago that I listened to a seminar paper where the financial crisis was modelled as a large negative productivity shock.

Only in a discipline which has deemed microfoundations as the only acceptable way of modelling can practitioners still feel embarrassed about including sticky prices because their microfoundations (the tricks mentioned above) are problematic . Only in that discipline can respected macroeconomists argue that because of these problematic microfoundations it is best to ignore something like sticky prices when doing policy work: and argument that would be laughed out of court in any other science. In no other discipline could you have a debate about whether it was better to model what you can microfound rather than model what you can see. Other economists understand this, but many macroeconomists still think this is all quite normal.   

Monday, 19 September 2016

In the long run ... our children are adults

One of the annoying aspects of the Brexit debate is that every piece of macroeconomic news, every survey or data point, is interpreted as evidence one way or another about the economic costs of Brexit. The problem with this is partly that Brexit has not happened yet, but more fundamentally the important costs of Brexit were always long term. The Treasury’s analysis of the permanent costs of Brexit looked 15 years ahead, because that is the kind of time period over which the full impacts will be felt.

That has another annoying implication, which is that it will be very difficult to ever know what the actual costs of Brexit will have been. GDP being 6% lower after 15 years (the Treasury’s central estimate based on a bilateral trade agreement) will have a noticeable impact on economic growth, but who knows what the counterfactual is? As I have noted many times, the trend growth in UK GDP per capita was a remarkably steady 2.25% until the financial crisis, but since then productivity growth has collapsed, so who knows what it might have been without Brexit.

It is true that with rational expectations the future will have an impact on the present. That is why the exchange rate fell sharply on news of the vote. As I keep pointing out, unless those in the markets change their minds, that depreciation makes every UK resident poorer, perhaps forever. Equally if everyone anticipated that their future income will be lower they should reduce consumption now. But one reason the vote went the way it did is that many people did not believe that Brexit will have a long run negative impact on their standard of living.

We can make the same point in a more concrete way by thinking about the problem facing the OBR as it makes its forecast before the Autumn Statement in November. Those expecting to see something dramatic in these forecasts may be disappointed, partly because Brexit is likely to actually occur in the middle of the OBR’s 5 year forecasting period. Where the OBR will have to come clean about their view on the long term impact of Brexit will not be until next summer, when it does its 50 year ahead projections.

While these long term costs were always what really mattered, I have the impression (see also Paul Krugman) that the campaign spent much more time talking about short run impacts. As I have argued, these could be significant but are much more uncertain because they are more complicated. (How much will the depreciation boost net exports, for example?) So why was there so much focus on the short term in the campaign, and why did some (mainly politicians) start talking about Brexit creating a short term crisis?

I suspect (and this is just a guess) that one reason is that talk about long run costs had little impact in the media and on voters. (This is what the polls suggest: voters seemed more prepared to agree that there might be short run costs to Brexit.) To an economist that seems odd, because the economics behind the long term impact is much more solid than what might happen in the short run. Of course Keynes had a famous phrase about all being dead in the long run, but as Simon Taylor points out he made that comment to counteract a tendency for some to dismiss problems like unemployment caused by recessions as unimportant because it will disappear in the long run.

One suggestion I have seen links the lack of traction over long run costs to the fact that Leave voters tended to be older, and therefore that they did not care too much about the long run. I think this is unfair: most of those older voters also have children who they care about.

I suspect the problem came from a basic misunderstanding that was deliberately encouraged by the Leave campaign, which is to see all economic analysis as an unconditional macroeconomic forecast. The retort ‘who knows what will happen in 15 years time’ resonates if that is what you are familiar with. Too many people who should have known better, or perhaps chose not to know better, failed to make the distinction between conditional and unconditional forecasts. We had the ridiculous charge that the Chancellor should not have said people will be worse off in 15 years time, because with normal growth in absolute terms they probably will not be.

To see how nonsensical this framing is, think about the advice any doctor will give you that by smoking you will be worse off. Society does not collectively shrug that off by saying who knows what will happen in 10 or more years time. Except of course some teenagers do say this and come to regret it. Nor, by the way, do people tell medics that they failed for decades to predict that smoking would kill people so why should we take any notice now. We are completely familiar with doctors giving us conditional forecasts, but for some reason some in the media kept trying to view any analysis of long term Brexit costs as another unconditional macroeconomic forecast. [1]

One implication of this is that the consequences of Brexit may never become obvious, particularly to those who voted to Leave. Of course economists will do the best they can with the data, but I doubt very much that their analysis will get through to most people. One of the many sad aspects of the Brexit decision is that those who helped make it possible will never be held responsible for their actions.

[1] Note also that these long term Brexit costs essentially came from empirical studies with fairly common sense theoretical content well grounded in evidence. 



Friday, 16 September 2016

Economics, DSGE and Reality: a personal story

As I do not win prizes very often, I thought I would use the occasion of this one to write something much more personal than I normally allow myself. But this mini autobiography has a theme involving something quite topical: the relationship between academic macroeconomics and reality, and in particular the debate over DSGE modelling and the lack of economics in current policymaking. [1]

I first learnt economics at Cambridge, a department which at that time was hopelessly split between different factions or ‘schools of thought’. I thought if this is what being an academic is all about I want nothing to do with it, and instead of doing a PhD went to work at the UK Treasury. The one useful thing about economics that Cambridge taught me (with some help from tutorials with Mervyn King) was that mainstream economics contained too much wisdom to be dismissed as fundamentally flawed, but also (with the help of John Eatwell) that economics of all kinds could easily be bent by ideology.

My idea that by working at the Treasury I could avoid clashes between different schools of thought was of course naive. Although the institution I joined had a well developed and empirically orientated Keynesian framework [2], it immediately came under attack from monetarists, and once again we had different schools using different models and talking past each other. I needed more knowledge to understand competing claims, and the Treasury kindly paid for me to do a masters at Birkbeck, with the only condition being that I subsequently return to the Treasury for at least 2 years. Birkbeck at the time was also a very diverse department (incl John Muellbauer, Richard Portes, Ron Smith, Ben Fine and Laurence Harris), but unlike Cambridge a faculty where the dedication to teaching trumped factional warfare.

I returned to the Treasury, which while I was away saw the election of Margaret Thatcher and its (correct) advice about the impact of monetarism completely rejected. I was, largely by accident, immediately thrust into controversy: first by being given the job of preparing a published paper evaluating the empirical evidence for monetarism, and then by internally evaluating the economic effects of the 1981 budget. (I talk about each here and here.) I left for a job at NIESR exactly two years after I returned from Birkbeck. It was partly that experience that informed this post about giving advice: when your advice is simply ignored, there is no point giving it.

NIESR was like a halfway house between academia and the Treasury: research, but with forecasting rather than teaching. I became very involved in building structural econometric models and doing empirical research to back them up. I built the first version of what is now called NIGEM (a world model widely used by policy making and financial institutions), and with Stephen Hall incorporated rational expectations and other New Classical elements into their domestic model.

At its best, NIESR was an interface between academic macro and policy. It worked very well just before 1990, where with colleagues I showed that entering the ERM at an overvalued exchange rate would lead to a UK recession. A well respected Financial Times journalist responded that we had won the intellectual argument, but he was still going with his heart that we should enter at 2.95 DM/£. The Conservative government did likewise, and the recession of 1992 inevitably followed.

This was the first public occasion where academic research that I had organised could have made a big difference to UK policy and people’s lives, but like previous occasions it did not do so because others were using simplistic and perhaps politically motivated reasoning. It was also the first occasion that I saw close up academics who had not done similar research but who had influence use that influence to support simplistic reasoning. It is difficult to understate the impact that had on me: being centrally involved in a policy debate, losing that debate for partly political reasons, and subsequently seeing your analysis vindicated but at the cost of people becoming unemployed.

My time at NIESR convinced me that I would find teaching more fulfilling than forecasting, so I moved to academia. The publications I had produced at NIESR were sufficient to allow me to become a professor. I went to Strathclyde University at Glasgow partly because they agreed to give temporary funding to two colleagues at NIESR to come with me so we could bid to build a new UK model. [3] At the time the UK’s social science research funding body, the ESRC, allocated a significant proportion of its funds to support econometric macromodels, subject to competitions every 4 years. It also funded a Bureau at Warwick university that analysed and compared the main UK models. This Bureau at its best allowed a strong link between academia and policy debate.

Our bid was successful, and in the model called COMPACT I would argue we built the first UK large scale structural econometric model which was New Keynesian but which also incorporated innovative features like an influence of (exogenous) financial conditions on intertemporal consumption decisions. [4] We deliberately avoided forecasting, but I was very pleased to work with the IPPR in providing model based economic analysis in regular articles in their new journal, many written with Rebecca Driver.

Our efforts impressed the academics on the ESRC board that allocated funds, and we won another 4 years funding, and both projects were subsequently rated outstanding by academic assessors. But the writing was on the wall for this kind of modelling in the UK, because it did not fit the ‘it has to be DSGE’ edict from the US. A third round of funding, which wanted to add more influences from the financial sector into the model using ideas based on work by Stiglitz and Greenwald, was rejected because our approach was ‘old fashioned’ i.e not DSGE. (The irony given events some 20 years later is immense, and helped inform this paper.)

As my modelling work had always been heavily theory based, I had no problem moving with the tide, and now at Exeter university with Campbell Leith we began a very successful stream of work looking at monetary and fiscal policy interactions using DSGE models. [5] We obtained a series of ESRC grants for this work, again all subsequently rated as outstanding. Having to ensure everything was microfounded I think created more heat than light, but I learnt a great deal from this work which would prove invaluable over the last decade.

The work on exchange rates got revitalised with Gordon Brown’s 5 tests for Euro entry, and although the exchange rate with the Euro was around 1.6 at the time, the work I submitted to the Treasury implied an equilibrium rate closer to 1.4. When the work was eventually published it had fallen to around 1.4, and stayed there for some years. Yet as I note here, that work again used an ’old fashioned’ (non DSGE) framework, so it was of no interest to journals, and I never had time to translate it (something Obstfeld and Rogoff subsequently did, but ignoring all that had gone before). I also advised the Bank of England on building its ‘crossover’ DSGE/econometric model (described here).

Although my main work in the 2000s was on monetary and fiscal policy, the DSGE framework meant I had no need to follow evolving macro data, in contrast to the earlier modelling work. With Campbell and Tatiana I did use that work to help argue for an independent fiscal council in the UK, a cause I first argued for in 1996. This time Conservative policymakers were listening, and our paper helped make the case for the OBR.

My work on monetary and fiscal interaction also became highly relevant after the financial crisis when interest rates hit their lower bound. In what I hope by now is a familiar story, governments from around the world first went with what macroeconomic theory and evidence would prescribe, and then in 2010 dramatically went the opposite way. The latter event was undoubtedly the underlying motivation for me starting to write this blog (coupled with the difficulty I had getting anything I wrote published in the Financial Times or Guardian).

When I was asked to write an academic article on the fiscal policy record of the Labour government, I discovered not just that the Coalition government’s constant refrain was simply wrong, but also that the Labour opposition seemed uninterested in what I found. Given what I found only validated what was obvious from key data series, I began to ask why no one in the media appeared to have done this, or was interested (beyond making fun) in what I had found. Once I started looking at what and how the media reported, I realised this was just one of many areas where basic economic analysis was just being ignored, which led to my inventing the term mediamacro.

You can see from all this why I have a love/hate relationship to microfoundations and DSGE. It does produce insights, and also ended the school of thought mentality within mainstream macro, but more traditional forms of macromodelling also had virtues that were lost with DSGE. Which is why those who believe microfounded modelling is a dead end are wrong: it is an essential part of macro but just should not be all academic macro. What I think this criticism can do is two things: revitalise non-microfounded analysis, and also stop editors taking what I have called ‘microfoundations purists’ too seriously.

As for macroeconomic advice and policy, you can see that austerity is not the first time good advice has been ignored at considerable cost. And for the few that sometimes tell me I should ‘stick with the economics’, you can see why given my experience I find that rather difficult to do. It is a bit like asking a chef to ignore how bad the service is in his restaurant, and just stick with the cooking. [6]

[1] This exercise in introspection is also prompted by having just returned from a conference in Cambridge, where I first studied economics. I must also admit that the Wikipedia page on me is terrible, and I have never felt it kosher to edit it myself, so this is a more informative alternative.

[2] Old, not new Keynesian, and still attached to incomes policies. And with a phobia about floating rates that could easily become ‘the end is nigh’ stuff (hence 1976 IMF).

[3] I hope neither regret their brave decision: Julia Darby is now a professor at Strathclyde and John Ireland is a deputy director in the Scottish Government.

[4] Consumption was of the Blanchard Yaari type, which allowed feedback from wealth to consumption. It was not all microfounded and therefore internally consistent, but it did attempt to track individual data series.

[5] The work continued when Campbell went to Glasgow, but I also began working with Tatiana Kirsanova at Exeter. I kept COMPACT going enough to be able to contribute to this article looking at flu pandemics, but even there one referee argued that the analysis did not use a ‘proper’ (i.e DSGE) model.

[6] At which point I show my true macro credentials in choosing analogies based on restaurants.