Economics as a religion

12 Jul, 2017 at 19:43 | Posted in Economics | 1 Comment

rapleyContrary to the tenets of orthodox economists, contemporary research suggests that, rather than seeking always to maximise our personal gain, humans still remain reasonably altruistic and selfless. Nor is it clear that the endless accumulation of wealth always makes us happier. And when we do make decisions, especially those to do with matters of principle, we seem not to engage in the sort of rational “utility-maximizing” calculus that orthodox economic models take as a given. The truth is, in much of our daily life we don’t fit the model all that well.

For decades, neoliberal evangelists replied to such objections by saying it was incumbent on us all to adapt to the model, which was held to be immutable – one recalls Bill Clinton’s depiction of neoliberal globalisation, for instance, as a “force of nature”. And yet, in the wake of the 2008 financial crisis and the consequent recession, there has been a turn against globalisation across much of the west …

It would be tempting for anyone who belongs to the “expert” class, and to the priesthood of economics, to dismiss such behaviour as a clash between faith and facts, in which the facts are bound to win in the end. In truth, the clash was between two rival faiths – in effect, two distinct moral tales. So enamoured had the so-called experts become with their scientific authority that they blinded themselves to the fact that their own narrative of scientific progress was embedded in a moral tale. It happened to be a narrative that had a happy ending for those who told it, for it perpetuated the story of their own relatively comfortable position as the reward of life in a meritocratic society that blessed people for their skills and flexibility. That narrative made no room for the losers of this order, whose resentments were derided as being a reflection of their boorish and retrograde character – which is to say, their fundamental vice. The best this moral tale could offer everyone else was incremental adaptation to an order whose caste system had become calcified. For an audience yearning for a happy ending, this was bound to be a tale of woe.

The failure of this grand narrative is not, however, a reason for students of economics to dispense with narratives altogether. Narratives will remain an inescapable part of the human sciences for the simple reason that they are inescapable for humans. It’s funny that so few economists get this, because businesses do.

Yes indeed, one would think it self-evident that “the facts are bound to win in the end.” But still mainstream economists seem to be impressed by the ‘rigour’ they bring to macroeconomics by their totally unreal New-Classical-New-Keynesian DSGE models and their rational expectations and micrcofoundations!

It is difficult to see why.

Take the rational expectations assumption. Rational expectations in the mainstream economists’ world implies that relevant distributions have to be time independent. This amounts to assuming that an economy is like a closed system with known stochastic probability distributions for all different events. In reality it is straining one’s beliefs to try to represent economies as outcomes of stochastic processes. An existing economy is a single realization tout court, and hardly conceivable as one realization out of an ensemble of economy-worlds, since an economy can hardly be conceived as being completely replicated over time. It is — to say the least — very difficult to see any similarity between these modelling assumptions and the expectations of real persons. In the world of the rational expectations hypothesis we are never disappointed in any other way than as when we lose at the roulette wheels. But real life is not an urn or a roulette wheel. And that’s also the reason why allowing for cases where agents make ‘predictable errors’ in DSGE models doesn’t take us any closer to a relevant and realist depiction of actual economic decisions and behaviours. If we really want to have anything of interest to say on real economies, financial crisis and the decisions and choices real people make we have to replace the rational expectations hypothesis with more relevant and realistic assumptions concerning economic agents and their expectations than childish roulette and urn analogies.

‘Rigorous’ and ‘precise’ DSGE models cannot be considered anything else than unsubstantiated conjectures as long as they aren’t supported by evidence from outside the theory or model. To my knowledge no in any way decisive empirical evidence has been presented.

No matter how precise and rigorous the analysis, and no matter how hard one tries to cast the argument in modern mathematical form, they do not push economic science forwards one single millimeter if they do not stand the acid test of relevance to the target. No matter how clear, precise, rigorous or certain the inferences delivered inside these models are, they do not say anything about real world economies.

Proving things ‘rigorously’ in DSGE models is at most a starting-point for doing an interesting and relevant economic analysis. Forgetting to supply export warrants to the real world makes the analysis an empty exercise in formalism without real scientific value.

no-miracles-in-science-please

Mainstream economists think there is a gain from the DSGE style of modeling in its capacity to offer some kind of structure around which to organise discussions. To me that sounds more like a religious theoretical-methodological dogma, where one paradigm rules in divine hegemony. That’s not progress. That’s the death of economics as a science.

Is the economic system self-adjusting?

12 Jul, 2017 at 13:15 | Posted in Economics | 2 Comments

Paul Krugman has repeatedly over the years argued that we should continue to use neoclassical hobby horses like IS-LM and AS-AD models. Here’s one example:

So why do AS-AD? … We do want, somewhere along the way, to get across the notion of the self-correcting economy, the notion that in the long run, we may all be dead, but that we also have a tendency to return to full employment via price flexibility. Or to put it differently, you do want somehow to make clear the notion (which even fairly Keynesian guys like me share) that money is neutral in the long run.

I seriously doubt that Keynes would have been impressed by having his theory being characterized with catchwords like “tendency to return to full employment” and “money is neutral in the long run.”

quote-our-thesis-is-that-the-idea-of-a-self-adjusting-market-implied-a-stark-utopia-such-an-karl-polanyi-120-53-85

One of Keynes’s central tenets — in clear contradistinction to the beliefs of mainstream neoclassical economists — is that there is no strong automatic tendency for economies to move towards full employment levels.

Money doesn’t matter in mainstream neoclassical macroeconomic models. That’s true. According to the ‘classical dichotomy,’ real variables — output and employment — are independent of monetary variables, and so enables mainstream economics to depict the economy as basically a barter system.

But in the real world in which we happen to live, money certainly does matter. Money is not neutral and money matters in both the short run and the long run:

The theory which I desiderate would deal … with an economy in which money plays a part of its own and affects motives and decisions, and is, in short, one of the operative factors in the situation, so that the course of events cannot be predicted in either the long period or in the short, without a knowledge of the behaviour of money between the first state and the last. And it is this which we ought to mean when we speak of a monetary economy.

J. M. Keynes A monetary theory of production (1933)

Krugman vs Syll on the IS-LM model

12 Jul, 2017 at 12:22 | Posted in Economics | Comments Off on Krugman vs Syll on the IS-LM model

islmSome time ago yours truly ventured to question Paul Krugman for his unadulterated devotion to the IS-LM model. For years self-proclaimed “proud neoclassicist” Paul Krugman had in endless harpings on the same IS-LM string told us about the splendour of the Hicksian invention.

Krugman’s response contained nothing new. In an earlier post on his blog, Krugman had argued that ‘Keynesian’ macroeconomics more than anything else “made economics the model-oriented field it has become.” In Krugman’s eyes, Keynes was a “pretty klutzy modeler,” and it was only thanks to Samuelson’s famous 45-degree diagram and Hicks’s IS-LM that things got into place. Although admitting that economists have a tendency to use ”excessive math” and “equate hard math with quality” he still vehemently defends — and always have — the mathematization of economics:

I’ve seen quite a lot of what economics without math and models looks like — and it’s not good.

Sure, ‘New Keynesian’ economists like Mankiw and Krugman — and their forerunners, ‘Keynesian’ economists like Paul Samuelson and (young) John Hicks — certainly have contributed to making economics more mathematical and “model-oriented.”

65547036But if these math-is-the-message-modelers aren’t able to show that the mechanisms or causes that they isolate and handle in their mathematically formalized macromodels also are applicable to the real world, these mathematical models are of limited value to our understandings of real world economies.

If economic regularities obtain they do it (as a rule) only because we engineered them for that purpose. Outside man-made mathematical-statistical models they are rare, or even non-existant. Unfortunately that makes most of contemporary mainstream neoclassical endeavours of mathematical economic modeling rather useless. And that goes for Krugman and the rest of the ‘New Keynesian’ family as well.

When it comes to modeling philosophy, Paul Krugman has in an earlier piece defended his position in the following words (my italics):

I don’t mean that setting up and working out microfounded models is a waste of time. On the contrary, trying to embed your ideas in a microfounded model can be a very useful exercise — not because the microfounded model is right, or even better than an ad hoc model, but because it forces you to think harder about your assumptions, and sometimes leads to clearer thinking. In fact, I’ve had that experience several times.

The argument is hardly convincing. If people put that enormous amount of time and energy that they do into constructing macroeconomic models, then they really have to be substantially contributing to our understanding and ability to explain and grasp real macroeconomic processes.

For years Krugman has in more than one article criticized mainstream economics for using too much (bad) mathematics and axiomatics in their model-building endeavours. But when it comes to defending his own position on various issues he usually himself ultimately falls back on the same kind of models. In his End This Depression Now — just to take one example — Krugman maintains that although he doesn’t buy “the assumptions about rationality and markets that are embodied in many modern theoretical models, my own included,” he still find them useful “as a way of thinking through some issues carefully.” When it comes to methodology and assumptions, Krugman obviously has a lot in common with the kind of model-building he otherwise criticizes.

The final court of appeal for macroeconomic models is the real world, and as long as no convincing justification is put forward for how the inferential bridging is made, macroeconomic model building is little more than hand waving that give us rather little warrant for making inductive inferences from models to the real world. If substantive questions about the real world are being posed, it is the formalistic-mathematical representations utilized to analyze them that have to match reality, not the other way around.

If macroeconomic models – no matter of what ilk – make assumptions, and we know that real people and markets cannot be expected to obey these assumptions, the warrants for supposing that conclusions or hypotheses can be bridged, are obviously non-justifiable.

A gadget is just a gadget — and brilliantly silly simple models — IS-LM included — do not help us working with the fundamental issues of modern economies any more than brilliantly silly complicated models — calibrated DSGE and RBC models included.

Marx and the Matthew effect

11 Jul, 2017 at 13:04 | Posted in Economics | 4 Comments

People who are short of money are often desperate to borrow and so willing to pay high interest rates to loan-sharks, payday lenders or car finance companies. If you lack negotiating power, you’ll get a bad deal.

matthew-effect3_603_316This is an example of the Matthew effect …

All of this means there’s some truth in the old cliché: “the rich get richer, the poor stay poor.” Although the ONS says that the UK has a relatively low rate of persistent poverty, I suspect this is the result of people shifting to just above the poverty line rather than into great fortune. Other ONS evidence (pdf) shows that half of those who were in the bottom income quintile in 2010 were still there in 2014, and that a further quarter were in the next quintile, implying that only a quarter made it into the top 60%.

You might think all this is trivial. Maybe. But there’s another arena in which the Matthew effect operates: capital-labour relations. Exploitation, thought Marx, arises because the worker’s poverty puts him in a weak bargaining position. He “has no other commodity for sale” than his labour-power and in “bringing his own hide to market…has nothing to expect but — a hiding.” This is still, generally, true. Yes, there are some instances whereby labour can exploit capital (such as top-league footballers or chief executives) but these are rare exceptions. In most cases, it’s capital that has bargaining power and labour that doesn’t, and this gives us another Matthew effect.

Chris Dillow

So true, so true. But you won’t find it in Greg Mankiw’s textbooks. Wonder why …

How ‘New Keynesian’ economics betrays Keynes

10 Jul, 2017 at 16:15 | Posted in Economics | 2 Comments

unemployed1Unless you have a PhD in economics, you probably think it uncontroversial to argue that we should be concerned about the unemployment rate. Those of you who have lost a job, or who have struggled to find a job on leaving school, college, or a university, are well aware that unemployment is a painful and dehumanizing experience. You may be surprised to learn that, for the past thirty-five years, the models used by academic economists and central bankers to understand how the economy works have not included unemployment as a separate category. In almost every macroeconomic seminar I attended, from 1980 through 2007, it was accepted that all unemployment is voluntary.

Roger Farmer

‘New Keynesian’ and New Classical microfounded DSGE models do not incorporate such a basic fact of reality as involuntary unemployment. Of course, working with microfounded representative agent models, this should — as argued in my paper Micro vs. macro — come as no surprise. If one representative agent is employed, all representative agents are. The kind of unemployment that occurs is voluntary, since it is only adjustments of the hours of work that these optimizing agents make to maximize their utility. In this model world, unemployment is always an optimal choice to changes in the labour market conditions. Hence, unemployment is totally voluntary. To be unemployed is something one optimally chooses to be.

To Keynes it was a sad fact of the world that not all unemployment is voluntary. But obviously not so to New Classical and ‘New Keynesian’ economists.

The perils of using Mickey Mouse models

10 Jul, 2017 at 10:02 | Posted in Economics | 1 Comment

When mainstream economists comment on the status of the Efficient Market Hypothesis, the really interesting questions as a rule drown in the usual pseudo science mumbo jumbo of four-factor models with two mispricing factors being better-performing than three-factor models, etc., etc.

Better read what Diane Coyle has to say about it:

I would defend using the assumption of rational choice as long as one realises that it is not a description of reality.

But there is one area where for 30 years economists – and others – have been making that mistake. That is unfortunately, of course, in the financial markets. Practitioners and policy makers acted as if the strong form of the Efficient Markets Hypothesis held true – in other words that prices instantly reflect all relevant information about the future – even though this evidently defies reality …

spock_in_2012_by_rabittooth-d4p2io9I think an honest conventionally-trained economist has to at least acknowledge that we grew intellectually lazy about this. Although we all knew at some level that the rational choice assumption was being made to bear too much weight, very few economists openly challenged its everyday use in justifying public policy decisions. Very few of us put this weight on it in our own work. But not all that many economists challenged its pervasive use in the public policy world …

The financial and economic crisis also spells a crisis for certain areas of economics, or approaches to economics. Financial economics and macroeconomics are particularly vulnerable. They are the subject areas where the consequences of the standard assumptions have been most damaging, because they are actually least valid. Financial market traders are not remotely like Star Trek’s Mr Spock, making rational calculations unaffected by emotion or by the decisions of other people. Macroeconomics – the study of how millions of individual decisions aggregate into economy-wide measures – is essentially ideological. How macroeconomists answer a question like ‘What will be the effect of cutting the budget deficit on growth next year?’ depends on their political views. This is not remotely a scientific area of the discipline. The consensus about macroeconomics during what’s been described as ‘the Great Moderation’ of the 1990s has entirely broken down.

Diane Coyle

The Efficient Market Hypothesis assumes — with no supporting evidence — that all information relevant to the pricing of financial assets is known by all market participants. That also implies having all relevant information on all future returns on those assets. If reality was like that it would be great. But it’s not. The future is uncertain. Forgetting that, and instead building models on ridiculous assumptions like rational expectations and efficient markets, Chicago style economists produce Mickey Mouse models of our economies.

Mickey Mouse modeling is for kids. It’s not science.

All Along The Watchtower (personal)

9 Jul, 2017 at 20:50 | Posted in Economics | 1 Comment

 

In loving memory of my brother Peter, a big Jimi Hendrix fan.

How to crush mainstream economics professors in debates

9 Jul, 2017 at 17:11 | Posted in Economics | 2 Comments

 

A must-see! [For English subtitles press the settings ‘wheel’ and choose]

And with a lesson to learn: being pompous and arrogant is of no avail when debating with smart and knowledgeable students …

How to filter obscurantist nonsense economics

8 Jul, 2017 at 16:49 | Posted in Economics | Comments Off on How to filter obscurantist nonsense economics

smellFollowing the greatest economic depression since the 1930s, Robert Solow in 2010 gave a prepared statement on “Building a Science of Economics for the Real World” for a hearing in the U. S. Congress. According to Solow modern macroeconomics has not only failed at solving present economic and financial problems, but is “bound” to fail. Building microfounded macromodels on “assuming the economy populated by a representative agent” — consisting of “one single combination worker-owner-consumer-everything-else who plans ahead carefully and lives forever” — do not pass the smell test: does this really make sense? Solow surmised that a thoughtful person “faced with the thought that economic policy was being pursued on this basis, might reasonably wonder what planet he or she is on.”

Conclusion: an economic theory or model that doesn’t pass the real world smell-test is just silly nonsense that doesn’t deserve our attention and therefore belongs in the dustbin.

Microfounded macroeconomic DSGE models immediately come to mind.

Those who want to build macroeconomics on microfoundations usually maintain that the only robust policies and institutions are those based on rational expectations and representative actors. As I tried to show in my paper Rational expectations — a fallacious foundation for macroeconomics in a non-ergodic world — there is really no support for that conviction at all. On the contrary. If we want to have anything of interest to say on real economies, financial crisis and the decisions and choices real people make, it is high time to replace macroeconomic models building on representative actors and rational expectations-microfoundations with more realist and relevant macroeconomic thinking.

If substantive questions about the real world are being posed, it is the formalistic-mathematical representations utilized to analyze them that have to match reality, not the other way around.

Jon Elster on mainstream economics — obscurant bullshit

8 Jul, 2017 at 09:17 | Posted in Economics | Comments Off on Jon Elster on mainstream economics — obscurant bullshit

In the present article I consider the less frequently phenomenon of “hard obscurantism”, a species of the genus scholarly obscurantism. In academic debates, a more common term for obscurantism is “bullshit” … One may perhaps, distinguish between obscure writers and obscurantist writers. The former aim at truth, but do not respect the norms for arriving at truth, such as focusing on causality, acting as the Devil’s Advocate, and generating falsifiable hypotheses. The latter do not aim at truth, and often scorn the very idea that there is such a thing as the truth …

bullshit-1-232x300Although I believe that the cases I have selected for analysis are somewhat representative of mainstream economic theorizing, I cannot make strong claims about how typical they are. What I can assert with great confidence is that the authors I have singled out are far from marginal, and in fact are at the core of the profession. Their numerous awards testify to this fact.

These writings have in common a somewhat uncanny combination of mathematical sophistication on the one hand and conceptual naiveté and empirical sloppiness on the other. The mathematics, which could have been a tool, is little more than toy. The steam engine was invented by Hero of Alexandria in the first century A. D., but he considered it mainly as a toy, not as a tool that could be put to productive use. He did apparently use it, though, for opening temple doors, so his engine wasn’t completely idling. Hard obscurantist models, too, may have some value as tools, but mostly they are toys.

I have pointed to the following objectionable practices:

1. Citing empirical evidence in a cavalier way, in the form of anecdotes, “impressions”, and unsubstantiated historical claims …

2. Adopting huge simplifications that make the empirical relevance of the results essentially nil …

3. Assuming that the probabilities in a stochastic process are known to the agents … or even in some sense optimal …

5. Assuming that the unconscious has the capacity to carry out inter temporal tradeoffs …

7. Assuming that agents can choose optimal preferences …

11. Adhering to the instrumental Chicago-style philosophy of explanation, which emphasizes as-if rationality and denies that the realism of assumptions is a relevant issue.

Jon Elster

It’s hard not to agree with Elster’s critique of mainstream economics and its practice of letting models and procedures become ends in themselves, without considerations of their lack of explanatory value as regards real world phenomena. For more on modern mainstream economics and this kind of wilfully silly obscurantism, yours truly self-indulgently recommend reading this article on RBC or this article on mainstream axiomatics.

Make Me Smile

8 Jul, 2017 at 08:43 | Posted in Varia | Comments Off on Make Me Smile

 

Why not even Paul Krugman is a real Keynesian

7 Jul, 2017 at 12:00 | Posted in Economics | 3 Comments

Keynes’s insights have enormous practical importance, according to Lance Taylor and Duncan Foley …

But isn’t Keynes now mainstream? No, say Foley and Taylor. The mainstream still sees economies as inherently moving to an optimal equilibrium … It still says demand causes short-run fluctuations, but only supply factors, such as the capital stock and technology, can affect long-run growth.

EVEN PAUL KRUGMAN, a self-described Keynesian, Nobel laureate, and New York Times columnist, writes in the 2012 edition of his textbook: “In the long run the economy is self-correcting: shocks to aggregate demand affect aggregate output in the short run but not in the long run” …

KeynesUpsidedownKrugman does point to one exception: If interest rates are nearly zero, as during the financial crisis, markets lose restorative force. But, Taylor asks, what’s the logic?

Keynes saw capitalism’s general state as allowing almost arbitrary unemployment: hence his “General Theory.” Full employment was a lucky exception.

To Taylor, calling full employment the general state and allowing one unlucky exception turns Keynes upside down.

Jonathan Schlefer

Iy is difficult not to agree with Taylor and Foley. To a large degree one does get the impression that Krugman thinks he is a Keynesian because he is a stout believer in John Hicks IS-LM interpretation of Keynes.

In a post on his blog, self-proclaimed “proud neoclassicist” Paul Krugman has argued that Keynesian macroeconomics more than anything else “made economics the model-oriented field it has become.” In Krugman’s eyes, Keynes was a “pretty klutzy modeler,” and it was only thanks to Samuelson’s famous 45-degree diagram and Hicks’s IS-LM that things got into place. Although admitting that economists have a tendency to use ”excessive math” and “equate hard math with quality” he still vehemently defends — and always have — the mathematization of economics:

I’ve seen quite a lot of what economics without math and models looks like — and it’s not good.

However, being a student of Hyman Minsky, yours truly very much doubt that IS-LM is an adequate reflection of the width and depth of Keynes’s insights on the workings of modern market economies.

Almost nothing in the post-General Theory writings of Keynes suggests him considering Hicks’s IS-LM anywhere near a faithful rendering of his thought. In Keynes’s canonical statement of the essence of his theory — in the 1937 Quarterly Journal of Economics article — there is nothing to even suggest that Keynes would have thought the existence of a Keynes-Hicks-IS-LM-theory anything but pure nonsense. John Hicks, the man who invented IS-LM in his 1937 Econometrica review of Keynes’ General Theory — “Mr. Keynes and the ‘Classics’. A Suggested Interpretation” — returned to it in an article in 1980 — “IS-LM: an explanation” — in Journal of Post Keynesian Economics. Self-critically he wrote that ”the only way in which IS-LM analysis usefully survives — as anything more than a classroom gadget, to be superseded, later on, by something better — is in application to a particular kind of causal analysis, where the use of equilibrium methods, even a drastic use of equilibrium methods, is not inappropriate.”

Sure, “New Keynesian” economists like Krugman — and their forerunners, “Keynesian” economists like Paul Samuelson and (young) John Hicks — certainly have contributed to making economics more mathematical and “model-oriented.”

wrong-tool-by-jerome-awBut if these math-is-the-message-modelers aren’t able to show that the mechanisms or causes that they isolate and handle in their mathematically formalized macromodels are stable in the sense that they do not change when we “export” them to our “target systems,” these mathematical models do only hold under ceteris paribus conditions and are consequently of limited value to our understandings, explanations or predictions of real economic systems. Outside man-made mathematical-statistical nomological machines, economic “laws” are rare, or even non-existant. Unfortunately that also makes most of contemporary mainstream neoclassical endeavours of mathematical economic modeling rather useless. And that also goes for Krugman.

In recent blogposts Paul Krugman has come back to his idea that it would be great if the Fed stimulated inflationary expectations so that investments would increase. I don’t have any problem with this idea per se, but I don’t think it’s of the stature that Krugman seems to think. But although I have written extensively on Knut Wicksell and consider him the greatest Swedish economist ever, I definitely — since Krugman portrays himself as “sorta-kinda Keynesian” — have to question his invocation of Knut Wicksell for his ideas on the “natural” rate of interest. Krugman writes (emphasis added):

There is nothing “artificial” or “unnatural” about low interest rates; they’re low because demand is low, and the Fed is responding appropriately. If anything, the “unnatural” situation is that rates are too high, because they’re constrained by the zero lower bound (rates can’t go below zero, except for some minor technical bobbles, because people can always just hold cash).

wicksell3Second, the Fed’s inability to get rates as low as they should be justifies a search for policies that can fill this policy gap. Fiscal stimulus is one such policy; unconventional monetary policies of various kinds are another. Actually, the natural policy — natural in a Wicksellian sense, and also the one that in terms of standard economics should produce the least distortion — would be a credible commitment to higher inflation.

Now consider what Keynes himself wrote in General Theory:

I am now no longer of the opinion that the [Wicksellian] concept of a ‘natural’ rate of interest, which previously seemed to me a most promising idea, has anything very useful or significant to contribute to our analysis. It is merely the rate of interest which will preserve the status quo; and, in general, we have no predominant interest in the status quo as such.

Paul Krugman has on his blog tried to explain why we should still use the neoclassical hobby horse Aggregate Supply-Aggregate Demand model:

So why do AS-AD? … We do want, somewhere along the way, to get across the notion of the self-correcting economy, the notion that in the long run, we may all be dead, but that we also have a tendency to return to full employment via price flexibility. Or to put it differently, you do want somehow to make clear the notion (which even fairly Keynesian guys like me share) that money is neutral in the long run.

Actually, this is the same unsubstantiated stuff you find in the “fairly Keynesian” Greg Mankiw’s textbooks.

Well, this “fairly Keynesian” guy is not impressed. And I doubt that Keynes himself would have been impressed by having his theory being characterized with catchwords like “tendency to return to full employment” and “money is neutral in the long run.”

As Taylor and Foley convincingly argue — Krugman is no real Keynesian.

Understanding the limits of statistical inference

6 Jul, 2017 at 18:35 | Posted in Statistics & Econometrics | 1 Comment

 

This is indeed an instructive video on what statistical inference is all about.

But we have to remember that economics and statistics are two quite different things, and as long as economists cannot identify their statistical theories with real-world phenomena there is no real warrant for taking their statistical inferences seriously.

Just as there is no such thing as a ‘free lunch,’ there is no such thing as a ‘free probability.’ To be able at all to talk about probabilities, you have to specify a model. If there is no chance set-up or model that generates the probabilistic outcomes or events -– in statistics one refers to any process where you observe or measure as an experiment (rolling a die) and the results obtained as the outcomes or events (number of points rolled with the die, being e. g. 3 or 5) of the experiment -– there, strictly seen, is no event at all.

Probability is a relational element. It always must come with a specification of the model from which it is calculated. And then to be of any empirical scientific value it has to be shown to coincide with (or at least converge to) real data generating processes or structures –- something seldom or never done in economics.

And this is the basic problem!

If you have a fair roulette-wheel, you can arguably specify probabilities and probability density distributions. But how do you conceive of the analogous ‘nomological machines’ for prices, gross domestic product, income distribution etc? Only by a leap of faith. And that does not suffice. You have to come up with some really good arguments if you want to persuade people into believing in the existence of socio-economic structures that generate data with characteristics conceivable as stochastic events portrayed by probabilistic density distributions! Not doing that, you simply conflate statistical and economic inferences.

And even worse — some economists using statistical methods think that algorithmic formalisms somehow give them access to causality. That is, however, simply not true. Assuming ‘convenient’ things like faithfulness or stability,is to assume what has to be proven. Deductive-axiomatic methods used in statistics do no produce evidence for causal inferences. The real casuality we are searching for is the one existing in the real-world around us. If there is no warranted connection between axiomatically derived statistical theorems and the real-world, well, then we haven’t really obtained the causation we are looking for.

Principal agent problems and incentive pay schemes

5 Jul, 2017 at 15:47 | Posted in Economics | Comments Off on Principal agent problems and incentive pay schemes

If bonus or “incentive pay” schemes work so well for senior executives and bankers, why does everyone not get them?

The conventional answer is that a bonus scheme or incentive plan will indeed encourage the recipients to make more money for the shareholders or clients on whose behalf they act …

juggleA classic paper on the “principal-agent problem” … by Bengt Holmstrom and Paul Milgrom pointed out that the conventional answer makes the mistake of assuming that jobs are simple and consist only of one task. In reality, agents — such as executives acting on behalf of shareholders — have multiple tasks with many dimensions. Some of these will be easier to measure than others …

The more complex the job, the more dimensions involved — as in being a corporate chief executive, say — the less justification there is for an incentive reward scheme. This is reinforced in the specific context of shareholder principals and chief executives, when the latter are responsible for the value of the assets they are managing on behalf of the company’s owners. Incentives linked to whatever can easily be measured lead agents to turn their efforts away from maintaining and enhancing the value of the asset over time …

As the economy becomes increasingly complex and intangible, monitoring and measuring seem ever harder. The simplistic case for bonus and incentive pay schemes grows ever weaker.

Indeed, the best arrangement would seem to be the opposite of the pattern we observe now. Corporate executives and senior bankers doing complex jobs involving many impossible-to-monitor activities are the last people who ought to be paid via an incentive scheme; while bonuses for fast-food workers or shop-floor employees make more sense.

Diane Coyle

At a deeper level this ‘puzzle’ confirms that the alleged close connection between productivity and remuneration postulated in mainstream income distribution theory simply does not exist.

The idea that capitalism is an expression of impartial market forces of supply and demand, bears but little resemblance to actual reality. Especially when it comes to  people that basically set their own salaries, you find a rather strong inclination for generous self-rewarding.

economic-mythWealth and income distribution, both individual and functional, in a market society is to an overwhelmingly high degree influenced by bargaining power, institutionalized political and economic norms, things that have relatively little to do with marginal productivity in complete and profit-maximizing competitive market models – not to mention how extremely difficult, if not outright impossible it is to empirically disentangle and measure different individuals’ contributions in the typical team work production that characterize modern societies; or, especially when it comes to ‘capital,’ what it is supposed to mean and how to measure it. Remunerations, a fortiori, do not necessarily correspond to any marginal product of different factors of production – or to ‘compensating differentials’ due to non-monetary characteristics of different jobs, natural ability, effort or chance.

The raven paradox

4 Jul, 2017 at 19:03 | Posted in Theory of Science & Methodology | 2 Comments

 

Besides illustrating that it is simply not a good description of how we make inferences in science to assume that non-black armchairs confirm the hypothesis that all ravens are black, Hempel’s paradox — at least in my reading of it — makes a good argument for a causal account of confirmation of empirical generalizations. Contrary to positivist theories of confirmation, the paradox shows that to have a good explanation in sciences, we have to make references to causes. Observed uniformity does not per se confirm generalizations. We also have to be able to show that uniformity does not appear by chance, but is the result of causal forces at work (such as e.g. genes in the case of ravens.

Assume you’re a Bayesian turkey (chicken) and hold a nonzero probability belief in the hypothesis H that “people are nice vegetarians that do not eat turkeys and that every day I see the sun rise confirms my belief.” For every day you survive, you update your belief according to Bayes’ Rule

P(H|e) = [P(e|H)P(H)]/P(e),

where evidence e stands for “not being eaten” and P(e|H) = 1. Given that there do exist other hypotheses than H, P(e) is less than 1 and a fortiori P(H|e) is greater than P(H). Every day you survive increases your probability belief that you will not be eaten. This is totally rational according to the Bayesian definition of rationality. Unfortunately — as Bertrand Russell famously noticed — for every day that goes by, the traditional Christmas dinner also gets closer and closer …

Studying only surface relations won’t do. Not knowing the nature of the causal structures and relations that give rise to what we observe, explanations serve us as badly as the one used by the turkey. Not knowing why things are the way they are, we run the same risk as the Russellian turkey.

No causality, no confirmation/explanation.

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