Archive for the 'Economics' Category

Precision as the enemy of knowledge

I have posted previously about the different ways in which knowledge may be represented.  A key learning of the discipline of Artificial Intelligence in its short life thus far is that not all representations are equal.    Indeed, more precise representations may provide less information, as in this example from cartography (from a profile of economist Paul Krugman):

Again, as in his [Krugman's] trade theory, it was not so much his idea [that regional ecomomic specializations were essentially due to historical accidents] that was significant as the translation of the idea into a mathematical language.  “I explained this basic idea” – of economic geography – “to a non-economist friend,” Krugman wrote, “who replied in some dismay, ‘Isn’t that pretty obvious?’  And of course it is.”  Yet, becaue it had not been well modelled, the idea had been disregarded by economists for years.  Krugman began to realize that in the previous few decades economic knowledge that had not been translated into [tractable analytical mathematical] models had been effectively lost, because economists didn’t know what to do with it.  His friend Craig Murphy, a political scientist at Wellesley, had a collection of antique maps of Africa, and he told Krugman that a similar thing had happened in cartography.  Sixteenth century maps of Africa were misleading in all kinds of ways, but they contained quite a bit of information about the continent’s interior – the River Niger, Timbuktu.  Two centuries later, mapmaking had become more accurate, but the interior of Africa had become a blank.  As standards for what counted as a mappable fact rose, knowledge that didn’t meet those standards – secondhand travellers’ reports, guesses hazarded without compasses or sextants – was discarded and lost.  Eventually, the higher standards paid off – by the nineteenth century the maps were filled in again – but for a while the sharpening of technique caused loss as well as gain. ” (page 45)

Reference:

Larissa MacFarquhar [2010]:  The deflationist:  How Paul Krugman found politicsThe New Yorker, 2010-03-01, pp. 38-49.




Concat 1: The GEC

A post to concatenate interesting material on the GFC and the GEC:




Mass customization of economic laws

Belatedly, I have just seen a column by John Kay in the FT of 13 April 2010 (subscribers only), entitled:  “Economics may be dismal, but it is not a science.” His column reminded me of Stephen Toulmin’s arguments in his book Cosmopolis about the universalizing tendencies of modern western culture these last four centuries, which I discussed here.

An excerpt from Kay’s column:

Both the efficient market hypothesis and DSGE [Dynamic Stochastic General Equilibrium models] are associated with the idea of rational expectations – which might be described as the idea that households and companies make economic decisions as if they had available to them all the information about the world that might be available. If you wonder why such an implausible notion has won wide acceptance, part of the explanation lies in its conservative implications. Under rational expectations, not only do firms and households know already as much as policymakers, but they also anticipate what the government itself will do, so the best thing government can do is to remain predictable. Most economic policy is futile.

So is most interference in free markets. There is no room for the notion that people bought subprime mortgages or securitised products based on them because they knew less than the people who sold them. When the men and women of Goldman Sachs perform “God’s work”, the profits they make come not from information advantages, but from the value of their services. The economic role of government is to keep markets working.

These theories have appeal beyond the ranks of the rich and conservative for a deeper reason. If there were a simple, single, universal theory of economic behaviour, then the suite of arguments comprising rational expectations, efficient markets and DSEG would be that theory. Any other way of describing the world would have to recognise that what people do depends on their fallible beliefs and perceptions, would have to acknowledge uncertainty, and would accommodate the dependence of actions on changing social and cultural norms. Models could not then be universal: they would have to be specific to contexts.

The standard approach has the appearance of science in its ability to generate clear predictions from a small number of axioms. But only the appearance, since these predictions are mostly false. The environment actually faced by investors and economic policymakers is one in which actions do depend on beliefs and perceptions, must deal with uncertainty and are the product of a social context. There is no universal economic theory, and new economic thinking must necessarily be eclectic. That insight is Keynes’s greatest legacy.

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The glass bead game of mathematical economics

Over at the economics blog, A Fine Theorem, there is a post about economic modelling.

My first comment is that the poster misunderstands the axiomatic method in pure mathematics.  It is not the case that “axioms are by assumption true”.  Truth is a bivariant relationship between some language or symbolic expression and the world.  Pure mathematicians using axiomatic methods make no assumptions about the relationship between their symbolic expressions of interest and the world.   Rather they deduce consequences from the axioms, as if those axioms were true, but without assuming that they are.    How do I know they do not assume their axioms to be true?  Because mathematicians often work with competing, mutually-inconsistent, sets of axioms, for example when they consider both Euclidean and non-Euclidean geometries, or when looking at systems which assume the Axiom of Choice and systems which do not.   Indeed, one could view parts of the meta-mathematical theory called Model Theory as being the formal and deductive exploration of multiple, competing sets of axioms.

On the question of economic modeling, the blogger presents the views of Gerard Debreu on why the abstract mathematicization of economics is something to be desired.   One should also point out the very great dangers of this research program, some of which we are suffering now.  The first is that people – both academic researchers and others – can become so intoxicated with the pleasures of mathematical modeling that they mistake the axioms and the models for reality itself.  Arguably the widespread adoption of financial models assuming independent and normally-distributed errors was the main cause of the Global Financial Crisis of 2008, where the errors of complex derivative trades (such as credit default swaps) were neither independent nor as thin-tailed as Normal distributions are.  The GFC led, inexorably, to the Great Recession we are all in now.

Secondly, considered only as a research program, this approach has serious flaws.  If you were planning to construct a realistic model of human economic behaviour in all its diversity and splendour, it would be very odd to start by modeling only that one very particular, and indeed pathological, type of behaviour examplified by homo economicus, so-called rational economic man.   Acting with with infinite mental processing resources and time, with perfect knowledge of the external world, with perfect knowledge of his own capabilities, his own goals, own preferences, and indeed own internal knowledge, with perfect foresight or, if not, then with perfect knowledge of a measure of uncertainty overlaid on a pre-specified sigma-algebra of events, and completely unencumbered with any concern for others, with any knowledge of history, or with any emotions, homo economicus is nowhere to be found on any omnibus to Clapham.  Starting economic theory with such a creature of fiction would be like building a general theory of human personality from a study only of convicted serial killers awaiting execution, or like articulating a general theory of evolution using only a hand-book of British birds.   Homo economicus is not where any reasonable researcher interested in modeling the real world would start from in creating a theory of economic man.

And, even if this starting point were not on its very face ridiculous, the fact that economic systems are complex adaptive systems should give economists great pause.   Such systems are, typically, not continuously dependent on their initial conditions, meaning that a small change in input parameters can result in a large change in output values.   In other words, you could have a model of economic man which was arbitrarily close to, but not identical with, homo economicus, and yet see wildly different behaviours between the two.  Simply removing the assumption of infinite mental processing resources creates a very different economic actor from the assumed one, and consequently very different properties at the level of economic systems.  Faced with such overwhelming non-continuity (and non-linearity), a naive person might expect economists to be humble about making predictions or giving advice to anyone living outside their models.   Instead, we get an entire profession labeling those human behaviours which their models cannot explain as “irrational”.

My anger at The Great Wen of mathematical economics arises because of the immorality this discipline evinces:   such significant and rare mathematical skills deployed, not to help alleviate suffering or to make the world a better place (as those outside Economics might expect the discipline to aspire to), but to explore the deductive consequences of abstract formal systems, systems neither descriptive of any reality, nor even always implementable in a virtual world.

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Complex Decisions

Most real-world business decisions are considerably more complex than the examples presented by academics in decision theory and game theory. What makes some decisions more complex than others? Here I list some features, not all of which are present in all decision situations.

Continue reading ‘Complex Decisions’

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Hey, Economics! Meet Politics!

Economists are fond of simplistic generalizations, which they refer to as “laws” (in imitation of Physics, itself showing its links to Theology), or as stylized facts.   Most such are, at best, default conclusions, since there are always exceptions.  Here are several, linked in a chain of inferences:

  • A successful single European currency requires a single European monetary policy.
  • A successful single European monetary policy requires a single European fiscal policy.
  • A successful single European fiscal policy requires fiscal transfers from one part of the European Union to another.
  • Fiscal transfers from one part of the European Union to another can only be undertaken over the long term by European institutions having democratic legitimacy.
  • To achieve democratic legitimacy for European institutions, the nations of Europe will require full political union.

This is not a new argument.  I first heard it put by Zambian economist Chiselebwe Ng’andwe in a paper read to a meeting of the African Association of Political Science in Salisbury (later Harare), Zimbabwe, in May 1981, talking about regional economic unions in Africa.   In today’s Guardian, Simon Jenkins refers back to a book about European integration by Larry Seidentop, published in 2000, which apparently makes a similar case about Europe.  Here is Ng’andwe in 1981:

Central banks play a pivotal role in the harmonization of fiscal, monetary and general economic policies.  Hence, separate central banks make it difficult to harmonize even those policy areas where joint arrangements exist such as a common tariff.

The Central bank is such an important institution for economic policy control that a joint central bank [in an economic union of states] needs total political harmony to function.  The necessary political harmony is not possible without political union.  Hence, a joint central bank and its potential benefits are simply not possible in a grouping of political[ly] independent states.  If one state wants some specific monetary policy to deal with an internal problem, a joint central bank will [op]pose some problems [policies?] unless the desired action is completely consistent with the economic and (or) political mood of the other countries.  The loss of some territorial capacity for fiscal and monetary manoeuvre entailed by a joint central bank may involve a greater loss in territorial economic growth than the territorial gain from joint economic actions. This possibility of net economic loss does not augur well for a joint central bank.  But even more important to the territorial political leaders is the loss of control over the key instruments of economic policy.  This loss can create frustrations in the internal economic and political policies of individual countries.

 . . .

Another signifance of joint policy instruments lie in the capacity of these instruments to reduce imbalances in the distribution of economic benefits.   .  .  .  Even in the U.S.A. where there is practically no government industrial and commercial activities, the availability of common fiscal and monetary policies enable[s] the central government to redistribute income throughout the federal states.

This redistribution may not be enough to remove inequalities completely, but it does remove the rough edges from any regional economic imbalances.”  (pp. 13-14)

Why is this argument not, then, widely understood?  Is it that some ideas are too comprehensible – in other words, apparently lacking in complexity or subtlety – to be understood by intelligent people? Or is that the political forces which benefit from the non-democratic European status quo are so strong as to prevent the adoption of democratic structures, and to muzzle the arguments for them?  As I recall, Ng’andwe’s talk was received very coldly by his audience, most of whom were keen on economic unions (between African countries), while maintaining national sovereignty in all other respects.

References:

Chiselebwe Ng’andwe [1981]:  Problems of Economic Integration in Africa.  Paper presented to the Fourth Bi-Annual Meeting of the African Association of Political Science (AAPS 1981).  Salisbury, Zimbabwe:  23-27 May 1981.

Larry Seidentop [2000]:  Democracy in Europe.  London, UK: Penguin.

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Verligte Economics

Nobel  laureate economist, Paul Krugman, has a blogpost summarizing his (and some of Brad DeLong’s) arguments against imposing fiscal austerity in the short-term.   I realize that the verkrampte wing of the economic commentariat seem to be in the majority at present, so unfortunately the wise good sense of Krugman and DeLong seems unlikely to prevail.  But I want to note their arguments for the record so that, 2 or 5 years from now, when we are again (or still) in recession, we can look back and weep.

So, one more time: here’s an attempt to put together some key arguments about why the rush to fiscal austerity is deeply misguided.

Let me start with the budget arithmetic, borrowing an approach from Brad DeLong. Consider the long-run budget implications for the United States of spending $1 trillion on stimulus at a time when the economy is suffering from severe unemployment.

That sounds like a lot of money. But the US Treasury can currently issue long-term inflation-protected securities at an interest rate of 1.75%. So the long-term cost of servicing an extra trillion dollars of borrowing is $17.5 billion, or around 0.13 percent of GDP.

And bear in mind that additional stimulus would lead to at least a somewhat stronger economy, and hence higher revenues. Almost surely, the true budget cost of $1 trillion in stimulus would be less than one-tenth of one percent of GDP – not much cost to pay for generating jobs when they’re badly needed and avoiding disastrous cuts in government services.

But we can’t afford it, say the advocates of austerity. Why? Because we must impose pain to appease the markets.

There are three problems with this claim.

First, it assumes that markets are irrational – that they will be spooked by stimulus spending and/or encouraged by austerity even though the long-run budget implications of such spending and/or austerity are trivial.

Second, we’re talking about punishing the real economy to satisfy demands that markets are not, in fact, making. It’s truly amazing to see so many people urging immediate infliction of pain when the US government remains able to borrow at remarkably low interest rates, simply because Very Serious People believe, in their wisdom, that the markets might change their mind any day now.

Third, all this presumes that if the markets were to lose faith in the US government, they would be reassured by short-term fiscal austerity. The available facts suggest otherwise: markets continue to treat Ireland, which has accepted savage austerity with little resistance, as being somewhat riskier than Spain, which has accepted austerity slowly and reluctantly.

In short: the demand for immediate austerity is based on the assertion that markets will demand such austerity in the future, even though they shouldn’t, and show no sign of making any such demand now; and that if markets do lose faith in us, self-flagellation would restore that faith, even though that hasn’t actually worked anywhere else.




This Much I Know (about CS and AI)

Inspired by The Guardian column of the same name, I decided to list here my key learnings of the last several years regarding Computer Science and Artificial Intelligence (AI). Few of these are my own insights, and I welcome comments and responses. From arguments I have had, I know that some of these statements are controversial; this fact surprises me, since most of them seem obvious to me. Statements are listed, approximately, from the more general to the more specific.




Catwoman, my old flame

Those of you paying attention to these lectures will realize how obsessed I am with Economics.  That flaxen-haired lady promised so much, but she has so many flaws and failings.   When we first meet her, it seems she is everything you could wish for:  she is concerned with how society should be organized, how people should be given material goods, how the benefits of new technology and material well-being should be shared with all, and how the poor should be enriched, so that they can spend their time on self-improving and fulfilling activities, like art and sport.  So much is promised!

But then, once the flirtation and seduction are over, her flaws become evident. I have been thinking about these flaws again, having just read Deirdre McCloskey’s superb 2002 pamphlet, The Secret Sins of Economics.  Many of McCloskey’s criticisms are ones I (and many others) have made before, but some are new.   I decided, for comparison, to list here my chief complaints with this blemished beauty, this feline seductress, Our Lady of the Catallacts.  Date her if you wish, but you should read these accounts by her ex-lovers before you do.

First, she is blinkered, often unable to see what is obvious to anyone else – that we are all shaped by social and cultural forces, and peer pressures.   Instead, Catwoman and her acolytes invariably assume an individualist explanation for any economic or social phenomenon, and then seek to demonstrate it.  McCloskey calls this a focus on the P-variables (price, individual prudence, profit, the profane) as distinct from the S-variables (solidarity, speech, stories, shame) which Anthropology, that Indiana Jones of academic disciplines – creative, unruly, a thorn in everyone else’s side – has focused on.   A classic example is Levitt and Dubner’s Freakonomics.

Because of her blindness to the social, Cat Lady mostly ignored (until recently) major aspects of society, such as Institutions, legal frameworks, norms, and power relationships, aspects which can make or fail the marketplaces she says she studies.   She can’t claim that no one mentioned these to her, since 19th-century economists such as Karl Marx made the study of these aspects the work of a lifetime, and their study has continued to the present by sociologists and anthropologists and political scientists.

She has also been blind to anything historical or temporal, as if all her work stood outside the mundane and messy world in which we live.  This blindness manifests itself most strongly in the complete disregard (until recently) for endowments:  how did we get to where we are?  So, for example, free trade theory says that if England produces textiles more cheaply than Portugal, and Portugal produces wine more cheaply then England, the two should trade textiles for wine, and wine for textiles.   And the choice of these products is a subtly clever one, obfuscating much, since wine needs sunshine and not too much rain, while textiles (in the 18th and early 19th centuries) needed lots of rain, in order that the damp air would ensure cotton threads did not break when woven by machines.   So, Portugal’s sunshine and Northern England’s rain, being part of the God-given climate, were natural advantages, beyond the control or manipulation of any temporal human powers.  Free trade seems to have been ordained by the Almighty. But why consider only England’s textiles and not Ireland’s?    The answer is that Ireland had no textile industry to speak of.  And just why is that?  After all, much of Ireland is as damp as the valleys of Lancashire.   The reason is that the owners of northern English textile factories lobbied the British authorities to exclude Irish-made textiles from entering England.  When Ireland lost its own Parliament in a hostile takeover by Westminster, this protectionism for English textiles was entrenched, and the growing British Empire provided the critical masses of customers to ensure bonuses in Bury and Bolton and Burnley.     (Is it any wonder that people in Ireland and India and elsewhere sought Independence, when colonialism so powerfully stifled economic aspirations.)  Northern England has no natural comparative advantage in textile production, at least, not when compared to Ireland, but an artificial, man-made advantage.  The same type of advantage, in fact, that South Korea today has in ship-building, or the USA in most computer and aerospace technologies.   Where, in the mainstream theory of free trade, are these aspects studied, or even mentioned?

And when, angered by these failings, you face her with them, the wench promises you that that was all in the past, and she will be different from now on.  Path dependence and network goods and institutional economics are all the rage, she says.   But then you find, she’s still up to her old tricks:  She says she’s building models of economic phenomena in order to understand, predict and control, just like physicists do.  But, although it looks like that’s what she’s doing, in fact her models are not models of real phenomena, but models of stylized abstractions of phenomena.  Her acolytes even use that very word – stylized – to describe the “facts” which they use to calibrate or test their models.

Of course, she will say, physicists do this too.  Newton famously assumed the planets were perfect spheres in order to predict their relative movements using his theory of gravitation.   But physicists later relax their assumptions, in order to build revised models, in a process that has continued since Newton to the present day.  Physicists also allow their models to be falsified by the data they collect, even when that data too is stylized, and overturned.     Instead, Catwoman is still assuming that people are maximizers of individual utility, with perfect foresight and unlimited processing capabilities, obeying the axiom of the irrelevance of independent alternatives, when all these assumptions have been shown to be false about us.   When was the last time a mainstream economic model was overturned?

Indeed, here is another of her flaws:  her loose grasp of reality.  She says we are always, all of us, acting in our own self-interest.  When you quiz this, pointing out (say) a friend who donated money to a charity, she replies that he is making himself feel better by doing something he thinks virtuous, and thus is maximizing his own self-interest.  Her assumption, it turns out, is unfalsifiable.   It is also naive and morally repugnant – and false!  Anyone with any experience of the world sees through this assumption straight away, which is why I think our feline friend is borderline autistic.   She just does not know much about real people and how they interact and live in the word. Who would want to step out with someone having such views, and unable to reconstruct them in the light of experience?

And, despite her claims to be grounded in the material world (Paul Samuelson:  “Economics is the study of how people and society end up choosing, with or without the use of money, to employ scarce productive resources that would have alternative uses,  . . .”), she sure is fond of metaphysical entities for which no hard evidence exists:  invisible hands, equilibria, perfect competition, free trade, commodities, in fact, the whole shebang.   As marketers say, the existence of a true commodity is evidence that a marketing manager is not doing his or her job.  In comparison, Richard Dawkins with his memes is a mere amateur in this creation of imaginary objects for religious veneration.

One could perhaps accept the scented candles and the imaginary friends if she was a little more humble and tolerant of the opinions of others.  But no, the feline femme fatale and her acolytes are among the most arrogant and condescending of any academic disciplines.  Read the recovering Chicago economist McCloskey for an account of this, if you don’t believe me.   McCloskey’s anecdotes and experiences were very familiar to me, especially that sneer from an economist who thinks you’ve not acted in your own self-interest – for example, by helping your colleagues or employer with something you are not legally required to do.  Indeed, the theft by economists from philosophers of the word “rational” to describe a very particular, narrow, autistic behavior is the best example of this.   Anyone whose behavior does not fit the models of mainstream economics can be thus be labeled irrational, and dismissed from further consideration as if insane.

Date her at your peril!  You have been warned!




Metrosexual competition

Writing about the macho world of pure mathematics (at least, in my experience, in analysis and group theory, less so in category theory and number theory, for example), led me to think that some academic disciplines seem hyper-competitive:  physics, philosophy and mainstream economics come to mind.  A problem for economics is that the domain of the discipline includes the study of competition, and the macho, hyper-competitive nature of academic economists has led them, I believe, astray in their thinking about the marketplace competition they claim to be studying.  They have assumed that their own nasty, bullying, dog-eat-dog world is a good model for the world of business.

If business were truly the self-interested, take-no-prisoners world of competition described in economics textbooks and assumed in mainstream economics, our lives would all be very different.  Fortunately, our world is mostly not like this.   One example is in telecommunications where companies compete and collaborate with each other at the same time, and often through the same business units.  For instance, British Telecommunications and Vodafone are competitors (both directly in the same product categories and indirectly through partial substitutes such as fixed and mobile services), and collaborators, through the legally-required and commercially-sensible inter-connections of their respective networks.  Indeed, for many years, each company was the other company’s largest customer, since the inter-connection of their networks means each company completes calls that originate on the other’s network; thus each company receives payments from the other.  Do you seek to drive your main competitor out of business when that competitor is also your largest customer?   Would you do this, as stupid as it seems, knowing that your competitor could retaliate (perhaps pre-emptively!) by disconnecting your network or reducing the quality of your calls that interconnect?  No rational business manager would do this, although perhaps an economist might. 

Nor would you destroy your competitors when you and they are sharing physical infrastructure  – co-locating switches in each other’s buildings, for example, or sharing rural cellular base stations, both of which are common in telecommunications.   And, to complicate matters, large corporate customers of telecommunications companies increasingly want direct access to the telco’s own switches, leading to very porous boundaries between companies and their suppliers.   Doctrines of nuclear warfare, such as mutually-assured destruction or iterated prisoners’ dilemma, are better models for this marketplace than the mainstream one-shot utility-maximizing models, in my opinion.

You might protest that telecommunications is a special case, since the product is a networked good – that is, one where a customer’s utility from a particular service may depend on the numbers of other customers also using the service.    However, even for non-networked goods, the fact that business usually involves repeated interactions with the same group of people (and is decidely not a one-shot interaction) leads to more co-operation than is found in an economist’s philosophy.   The empirical studies of hedge funds undertaken by sociologist Donald MacKenzie, for example, showed the great extent to which hedge fund managers rely in their investment decisions on information they receive from their competitors.  Because everyone hopes to come to work tomorrow and the day after, as well as today, there are strong incentives on people not to  mis-use these networks through, for instance, disseminating false or explicitly-self-serving information.  

It’s a dog-help-dog world out there!

Reference:

Iain Hardie and Donald MacKenzie [2007]:  Assembling an economic actor: the agencement of a hedge fund. The Sociological Review, 55 (1): 57-80.

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