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Modern economics — a severe case of model Platonism

August 30, 2018 4 comments

from Lars Syll

That is the great thing about abstraction. Working with what can be called ‘flex price’ models does not imply that you think price rigidity is unimportant, but instead that it can often be ignored if you want to focus on other processes.

Simon Wren-Lewis

When applying deductivist thinking to economics, mainstream economists like Wren-Lewis usually set up ‘as if’ models based on a set of tight axiomatic assumptions from which consistent and precise inferences are made. The beauty of this procedure is, of course,​ that if the axiomatic premises are true, the conclusions necessarily follow. The snag is that if the models are to be relevant, we also have to argue that their precision and rigour still holds when they are applied to real-world situations. They often do not. When addressing real economies, the idealizations necessary for the deductivist machinery to work — as e. g. ‘flex price’ models — simply do not hold.

If the real world is fuzzy, vague and indeterminate, then why should our models build upon a desire to describe it as precise and predictable? The logic of idealization is a marvellous tool in mathematics and axiomatic-deductivist systems, but a poor guide for action in real-world systems, in which concepts and entities are without clear boundaries and continually interact and overlap.  Read more…

Technobabble economics

August 27, 2018 4 comments

from Lars Syll

ZJL-Head-In-Sand

Deductivist modelling​ endeavours and an overly simplistic use of statistical and econometric tools are sure signs of the explanatory hubris that still haunts mainstream economics.

In an interview Robert Lucas says

the evidence on postwar recessions … overwhelmingly supports the dominant importance of real shocks.

So, according to Lucas, changes in tastes and technologies should be able to explain the main fluctuations in e.g. the unemployment that we have seen during the last six or seven decades. But really — not even a Nobel laureate could in his wildest imagination come up with any warranted and justified explanation solely based on changes in tastes and technologies.

The Chicago übereconomist is simply wrong. But how do we protect ourselves from this kind of scientific nonsense? In The Scientific Illusion in Empirical Macroeconomics Larry Summers has a suggestion well worth considering — not the least since it makes it easier to understand how mainstream economics actively contribute to causing economic crises rather than to solve them:  Read more…

The cost of focusing on general equilibrium theory

August 25, 2018 18 comments

from Lars Syll

The largest problem with the economics profession’s focus on general equilibrium theory is the opportunity costs of that exploration. Important policy problems are not addressed. Consider Pareto optimality and the welfare theorems, which Fisher sees as the underpinnings of Western capitalism. In a world, such as ours, where property rights cannot be allocated effortlessly and costlessly, economist’s welfare theorems have little policy relevance. Does a policy maker care whether any Pareto efficient allocation can be decentralized as a competitive general equilibrium? The chance of discovering a real-world Pareto optimal policy that can be shown to harm no one in some infinitesimal way is essentially nil.

what ifBy focusing their theoretical policy analysis on Pareto optimal policies, economists avoid coming to grips theoretically with the messy value judgments that must be made in the policy space, which means that their theoretical models provide little guidance on how to deal with the messy problems of actual policy that are designed to achieve both efficiency and fairness. In its almost exclusive focus on efficiency, modern economists have moved away from Classical economist’s utilitarian moral philosophy that underlay Classical economist’s support of markets. Classical economists supported markets because they worked reasonably well in the real world, not because of any deductive proof of the benefits of markets.

Dave Colander

Reformulating the economics curriculum

August 23, 2018 6 comments

from Lars Syll

Having gone through a handful of the most frequently used textbooks of economics at the undergraduate level today, I can only conclude that the models that are presented in these modern mainstream textbooks try to describe and analyze complex and heterogeneous real economies with a single rational-expectations-robot-imitation-representative-agent.

madiThat is, with something that has absolutely nothing to do with reality. And — worse still — something that is not even amenable to the kind of general equilibrium analysis that they are thought to give a foundation for, since Hugo Sonnenschein (1972), Rolf Mantel (1976) and Gérard Debreu (1974) unequivocally showed that there did not exist any condition by which assumptions on individuals would guarantee neither stability nor uniqueness of the equilibrium solution.

So what modern economics textbooks present to students are really models built on the assumption that an entire economy can be modelled as a representative actor and that this is a valid procedure. But it is not, as the Sonnenschein-Mantel-Debreu theorem irrevocably has shown.

Of course one could say that it is too difficult on undergraduate levels to show why the procedure is right and to defer it to master and doctoral courses. It could justifiably be reasoned that way — if what you teach your students is true, if The Law of Demand is generalizable to the market level, and the representative actor is a valid modelling abstraction! But in this case, it is demonstrably known to be false, and therefore this is nothing but a case of scandalous intellectual dishonesty. It’s like telling your students that 2 + 2 = 5 and hope that they will never run into Peano’s axioms of arithmetics.

For almost forty years mainstream economics itself has lived with a theorem that shows the impossibility of extending the microanalysis of consumer behaviour to the macro level (unless making patently and admittedly insane assumptions). Still after all these years pretending in their textbooks that this theorem does not exist — none of the textbooks I investigated even mention the existence of the Sonnenschein-Mantel-Debreu theorem — is really outrageous.

Econophysics

August 21, 2018 11 comments

from Lars Syll

Unfortunately, nothing is more dangerous than dogmas donned with scientific feathers. The current crisis might offer an excellent occasion for a paradigm
change, previously called for by prominent economists like John Maynard Keynes, Alan Kirman and Steve Keen. They have forcefully highlighted the shortcomings
and contradictions of the classical economictheory, but progress has been slow. The task looks so formidable that some economists argue that it is better to stick with the implausible but well-corseted theory of perfectly rational agents than to venture into modelling the infinite number of ways agents can be irrational.

miracle_cartoonPhysicists, however, feel uncomfortable with theories not borne out by (or even blatantly incompatible with) empirical data. But could the methodology of physics really contribute to the much-awaited paradigm shift in economics? …

Econophysics is in fact a misnomer, since most of its scope concerns financial markets. To some economists, finance is a relatively minor subfield and any contribution, even the most significant, can only have a limited impact on economics science at large. I personally strongly disagree with this viewpoint: recent events confirm that hiccups in the financial markets can cripple the entire economy.  Read more…

“I never learned maths, so I had to think”

August 17, 2018 18 comments

from Lars Syll

Professors may find themselves ill-prepared for the macro classroom. To become academics they had to answer erudite questions posed by more senior members of the discipline. To become good teachers of introductory macro, they have to give clear answers to muddled students. That requires an intuitive feel for the subject. It is not enough to crank through the equations.

roweIndeed, Mr Rowe attributes part of his success as a teacher to his shortcomings as a mathematician. He quotes Joan Robinson, another clear expositor of macroeconomics: “I never learned maths, so I had to think.” Because the answers did not leap out at him from the equations, he had to dwell on the economic behaviour underneath the algebra.

Macroeconomics is difficult to teach partly because its theorists (classical, Keynesian, monetarist, New Classical and New Keynesian, among others) disagree about so much. It is difficult also because the textbooks disagree about so little.

The Economist

Easterlin’s paradox or why economic growth does not make us happier

August 15, 2018 14 comments

from Lars Syll

In Easterlin’s (1974) seminal paper, he finds that within any one country, in cross sectional studies, there was a strong correlation between income and happiness. One would easily conclude that money can buy happiness. However, looking at a cross section of countries, one comes to a different conclusion …

For 10 of the 14 countries surveyed, the happiness ranking is about the same, even though the income per capita changes by a factor of 30 from $140 to $2,000 …

easterlinThe finding of strong correlation between income and happiness disappears when comparisons are made across countries. Similarly, there is no correlation between happiness and income in the long run within a single country … Easterlin (2001) cites several studies which show that, despite tremendous increases in GNP per capita, the level of happiness in European and Latin American has remained virtually constant over decades.

The startling implication of these empirical findings is that the stress being placed on economic growth is entirely misplaced. Growth has no clear relation to happiness. The profession of economics, as well as policy makers all over the world are directly threatened by these findings, which suggest radical changes in how to organise economic affairs …

The implicit proposition of utility theory that the sole route to happiness is maximisation of consumption contradicts with the empirical evidence: this proposition is true only in the short run. This short run validity creates a dangerous illusion of long run validity; understanding this has dramatic policy implications. If happiness is determined by relative comparisons, then one can achieve greater happiness by reducing inequalities, and also by reducing the standards of living for everyone. This will lower the benchmark and make it easier for everyone on the planet to be happy in comparison with this benchmark.

Asad Zaman & Mehmet Karacuka

So much for value-free economics

August 15, 2018 9 comments

from Lars Syll

Back in 1992, New Jersey raised the minimum wage by 18 per cent while its neighbour state, Pennsylvania, left its minimum wage unchanged. Unemployment in New Jersey should — according to mainstream economics textbooks — have increased relative to Pennsylvania. However, when economists David Card and Alan Krueger gathered information on fast food restaurants in the two states, it turned out that unemployment had actually decreased in New Jersey relative to that in Pennsylvania. Counter to mainstream demand theory we had an anomalous case of a backward-sloping supply curve.

And, of course, all those non-ideological and value-free scientific economists out there were überjoyed and prepared to revise their theories …

jp-imgresI’ve subsequently stayed away from the minimum wage literature for a number of reasons. First, it cost me a lot of friends. People that I had known for many years, for instance, some of the ones I met at my first job at the University of Chicago, became very angry or disappointed. They thought that in publishing our work we were being traitors to the cause of economics as a whole.

David Card

Money in perspective

August 13, 2018 13 comments

from Lars Syll

keWhen the accumulation of wealth is no longer of high social importance, there will be great changes in the code of morals. We shall be able to rid ourselves of many of the pseudo-moral principles which have hag-ridden us for two hundred years, by which we have exalted some of the most distasteful of human qualities into the position of the highest virtues. We shall be able to afford to dare to assess the money-motive at its true value. The love of money as a possession — as distinguished from the love of money as a means to the enjoyments and realities of life — will be recognized for what it is, a somewhat disgusting morbidity, one of those semi-criminal, semi-pathological propensities which one hands over with a shudder to the specialists in mental disease.

Modern macro — a total waste​ of time

August 13, 2018 3 comments

from Lars Syll

While one can understand that some of the elements in DSGE models seem to appeal to Keynesians at first sight, after closer examination, these models are in fundamental contradiction to Post-Keynesian and even traditional Keynesian thinking. The DSGE model is a model in which output is determined in the labour market as in New Classical models and in which aggregate demand plays only a very secondary role, even in the short run.

In addition, given the fundamental philosophical problems presented for the use of DSGE models for policy simulation, namely the fact that a number of parameters used have completely implausible magnitudes and that the degree of freedom for different parameters is so large that DSGE models with fundamentally different parametrization (and therefore different policy conclusions) equally well produce time series which fit the real-world data, it is also very hard to understand why DSGE models have reached such a prominence in economic science in general.

Sebastian Dullien

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Why data is not enough to answer scientific questions

August 10, 2018 6 comments

from Lars Syll

The Book of Why_coverIronically, the need for a theory of causation began to surface at the same time that statistics came into being. In fact modern statistics hatched out of the causal questions that Galton and Pearson asked about heredity and out of their ingenious attempts to answer them from cross-generation data. Unfortunately, they failed in this endeavor and, rather than pause to ask “Why?”, they declared those questions off limits, and turned to develop a thriving, causality- free enterprise called statistics.

This was a critical moment in the history of science. The opportunity to equip causal questions with a language of their own came very close to being realized, but was squandered. In the following years, these questions were declared unscientific and went underground. Despite heroic efforts by the geneticist Sewall Wright (1889-1988), causal vocabulary was virtually prohibited for more than half a century. And when you prohibit speech, you prohibit thought, and you stifle principles, methods, and tools.

Readers do not have to be scientists to witness this prohibition. In Statistics 101, every student learns to chant: “Correlation is not causation.” With good reason! The rooster crow is highly correlated with the sunrise, yet it does not cause the sunrise.

Unfortunately, statistics took this common-sense observation and turned it into a fetish. It tells us that correlation is not causation, but it does not tell us what causation is. In vain will you search the index of a statistics textbook for an entry on “cause.” Students are never allowed to say that X is the cause of Y — only that X and Y are related or associated.

A popular idea in quantitative social sciences is to think of a cause (C) as something that increases the probability of its effect or outcome (O). That is:   Read more…

Rethinking public budget

August 8, 2018 21 comments

from Lars Syll

The balanced budget paradox is probably one of the most devastating phenomena haunting our economies. The harder politicians — usually on the advice of establishment economists — try to achieve balanced budgets for the public sector, the less likely they are to succeed in their endeavour. And the more the citizens have to pay for the concomitant austerity policies these wrong-headed politicians and economists recommend as “the sole solution.”

One of the most effective ways of clearing up this most serious of all semantic confusions is to point out that private debt differs from national debt in being external … A variant of the false analogy is the declaration that national debt puts an unfair burden on our children, who are thereby made to pay for our extravagances. Very few economists need to be reminded that if our children or grandchildren repay some of the national debt these payments will be made to our children or grandchildren and to nobody else. Taking them altogether they will no more be impoverished by making the repayments than they will be enriched by receiving them.

Abba Lerner The Burden of the National Debt (1948)

Few issues in politics and economics are nowadays more discussed — and less understood — than public debt. Read more…

The essence​ of scientific reasoning​

August 6, 2018 18 comments

from Lars Syll

In science we standardly use a logically non-valid inference — the fallacy of affirming the consequent — of the following form:

(1) p => q
(2) q
————-
p

or, in instantiated form

(1) ∀x (Gx => Px)

(2) Pa
————
Ga

Although logically invalid, it is nonetheless a kind of inference — abduction — that may be factually strongly warranted and truth-producing.

holmes-quotes-about-holmesFollowing the general pattern ‘Evidence  =>  Explanation  =>  Inference’ we infer something based on what would be the best explanation given the law-like rule (premise 1) and an observation (premise 2). The truth of the conclusion (explanation) is nothing that is logicallygiven, but something we have to justify, argue for, and test in different ways to possibly establish with any certainty or degree. And as always when we deal with explanations, what is considered best is relative to what we know of the world. In the real world, all evidence is relational (evidence only counts as evidence in relation to a specific hypothesis) and has an irreducible holistic aspect. We never conclude that evidence follows from a hypothesis simpliciter, but always given some more or less explicitly stated contextual background assumptions. All non-deductive inferences and explanations are necessarily context-dependent.  Read more…

The state of ‘New Keynesian’ economics

July 31, 2018 12 comments

from Lars Syll

Tnkhe standard NK [New Keynesian] model, like most of its predecessors in the RBC literature, represents an economy inhabited by an infinitely-lived representative household. That assumption, while obviously unrealistic, may be justified by the belief that, like so many other aspects of reality, the finiteness of life and the observed heterogeneity of individuals along many dimensions … can be safely ignored for the purposes of explaining aggregate fluctuations and their interaction with monetary policy, with the consequent advantages in terms of tractability …

There is a sense in which none of the extensions of the NK model described above can capture an important aspect of most financial crises, namely, a gradual build-up of financial imbalances leading to an eventual “crash” characterized by defaults, sudden-stops of credit flows, asset price declines, and a large contraction in aggregate demand, output and employment. By contrast, most of the models considered above share with their predecessors a focus on equilibria that take the form of stationary fluctuations driven by exogenous shocks. This is also the case in variants of those models that allow for financial frictions of different kinds and which have become quite popular as a result of the financial crisis … The introduction of financial frictions in those models often leads to an amplification of the effects of non-financial shocks. It also makes room for additional sources of fluctuations related to the presence of financial frictions … or exogenous changes in the tightness of borrowing constraints​ … Most attempts to use a version of the NK models to explain the “financial crisis,” however, end up relying on a large exogenous shock that impinges on the economy unexpectedly, triggering a large recession, possibly amplified by a financial accelerator mechanism embedded in the model. It is not obvious what the empirical counterpart to such an exogenous shock is.

Jordi Gali

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Where modern macroeconomics went wrong

July 25, 2018 8 comments

from Lars Syll

In issue 1-2 (2018) of Oxford Review of Economic Policy, the editors have invited some well-known contemporary mainstream macroeconomists (including e.g. Simon Wren-Lewis, Randall Wright, Olivier Blanchard, Ricardo Reis, Joseph Stiglitz) to give their views on how to rebuild macroeconomic theory for the future.

economist_cover_oh_fuck_september_2008Some of the contributions are interesting to read. Others — like Wren-Lewis and Blanchard — seem to think that we can basically just go on with our microfounded DSGE models and complement them with one or other structural econometric model (SEM). Two bads, however, do not add up to one good.

Joseph Stiglitz article on Where Modern Macroeconomics Went Wrong acknowledges that his approach “and that of DSGE models begins with the same starting point: the competitive equilibrium model of Arrow and Debreu.” That is, however, probably also the reason why Stiglitz’ suggestions for rebuilding macroeconomics don’t go far enough.

It’s strange that mainstream macroeconomists still stick to a general equilibrium paradigm more than forty years after the Sonnenschein-Mantel-Debreu theorem — SMD — devastatingly showed that it  is an absolute non-starter for building realist and relevant macroeconomics:  Read more…

Mainstream economics and neoliberalism — what is the difference?

July 23, 2018 12 comments

from Lars Syll

Oxford professor Simon Wren-Lewis had a post up some time ago commenting on traction gaining ‘attacks on mainstream economics’:

neoOne frequent accusation … often repeated by heterodox economists, is that mainstream economics and neoliberal ideas are inextricably linked. Of course economics is used to support neoliberalism. Yet I find mainstream economics full of ideas and analysis that permits a wide ranging and deep critique of these same positions. The idea that the two live and die together is just silly.

The same Wren-Lewis has also felt it necessary to defend mainstream economics against critique waged against it from Phil Mirowski:

Mirowski overestimates the extent to which neoliberal ideas have become ’embedded in economic theory’, and underestimates the power that economic theory and evidence can have over even those academic economists who might have a neoliberal disposition. If the tide of neoliberal thought is going to be turned back, economics is going to be important in making that happen.

Wren-Lewis admits that “Philip Mirowski is a historian who has written a great deal about both the history of economics as a discipline and about neoliberalism’ and that Mirowski ‘knows much more about the history of both subjects than I do.” Fair enough, but there are simple remedies for the lack of knowledge.  Read more…

What’s the use of economics?

July 21, 2018 10 comments

from Lars Syll

The simple question that was raised during a recent conference … was to what extent has – or should – the teaching of economics be modified in the light of the current economic crisis? The simple answer is that the economics profession is unlikely to change. Why would economists be willing to give up much of their human capital, painstakingly nurtured for over two centuries? For macroeconomists in particular, the reaction has been to suggest that modifications of existing models to take account of ‘frictions’ or ‘imperfections’ will be enough to account for the current evolution of the world economy. The idea is that once students have understood the basics, they can be introduced to these modifications.

However, other economists such as myself feel that we have finally reached the turning point in economics where we have to radically change the way we conceive of and model the economy. The crisis is an opportune occasion to carefully investigate new approaches … Rather than making steady progress towards explaining economic phenomena professional economists have been locked into a narrow vision of the economy. We constantly make more and more sophisticated models within that vision until, as Bob Solow put it, “the uninitiated peasant is left wondering what planet he or she is on” …

Every student in economics is faced with the model of the isolated optimising individual who makes his choices within the constraints imposed by the market … The student then moves on to macroeconomics and is told that the aggregate economy or market behaves just like the average individual she has just studied. She is not told that these general models in fact poorly reflect reality. For the macroeconomist, this is a boon since he can now analyse the aggregate allocations in an economy as though they were the result of the rational choices made by one individual. The student may find this even more difficult to swallow when she is aware that peoples’ preferences, choices and forecasts are often influenced by those of the other participants in the economy. Students take a long time to accept the idea that the economy’s choices can be assimilated to those of one individual.

Alan Kirman What’s the use of economics?

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Regression analysis — a case of wishful thinking

July 19, 2018 2 comments

from Lars Syll

The impossibility of proper specification is true generally in regression analyses across the social sciences, whether we are looking at the factors affecting occupational status, voting behavior, etc. The problem is that as implied by the conditions for regression analyses to yield accurate, unbiased estimates, you need to investigate a phenomenon that has underlying mathematical regularities – and, moreover, you need to know what they are. Neither seems true. I have no reason to believe that the way in which multiple factors affect earnings, student achievement, and GNP have some underlying mathematical regularity across individuals or countries. More likely, each individual or country has a different function, and one that changes over time. Even if there was some constancy, the processes are so complex that we have no idea of what the function looks like.

regressionResearchers recognize that they do not know the true function and seem to treat, usually implicitly, their results as a good-enough approximation. But there is no basis for the belief that the results of what is run in practice is anything close to the underlying phenomenon, even if there is an underlying phenomenon. This just seems to be wishful thinking. Most regression analysis research doesn’t even pay lip service to theoretical regularities. But you can’t just regress anything you want and expect the results to approximate reality. And even when researchers take somewhat seriously the need to have an underlying theoretical framework – as they have, at least to some extent, in the examples of studies of earnings, educational achievement, and GNP that I have used to illustrate my argument – they are so far from the conditions necessary for proper specification that one can have no confidence in the validity of the results.

Steven J. Klees 

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The main reason why almost all econometric models are wrong

July 17, 2018 23 comments

from Lars Syll

How come that econometrics and statistical regression analyses still have not taken us very far in discovering, understanding, or explaining causation in socio-economic contexts? That is the question yours truly has tried to answer in an article published in the latest issue of World Economic Association Commentaries:

The processes that generate socio-economic data in the real world cannot just be assumed to always be adequately captured by a probability measure. And, so, it cannot be maintained that it even should be mandatory to treat observations and data — whether cross-section, time series or panel data — as events generated by some probability model. The important activities of most economic agents do not usually include throwing dice or spinning roulette-wheels. Data generating processes — at least outside of nomological machines like dice and roulette-wheels — are not self-evidently best modelled with probability measures.

EGOBILD2017When economists and econometricians — often uncritically and without arguments — simply assume that one can apply probability distributions from statistical theory on their own area of research, they are really skating on thin ice. If you cannot show that data satisfies all the conditions of the probabilistic nomological machine, then the statistical inferences made in mainstream economics lack sound foundations.

Statistical — and econometric — patterns should never be seen as anything other than possible clues to follow. Behind observable data, there are real structures and mechanisms operating, things that are — if we really want to understand, explain and (possibly) predict things in the real world — more important to get hold of than to simply correlate and regress observable variables.

Statistics cannot establish the truth value of a fact. Never has. Never will.

Hard and soft science — a flawed dichotomy

July 16, 2018 15 comments

from Lars Syll

The distinctions between hard and soft sciences are part of our culture … But the important distinction is really not between the hard and the soft sciences. Rather, it is between the hard and the easy sciences. Easy-to-do science is what those in physics, chemistry, geology, and some other fields do. Hard-to-do science is what the social scientists do and, in particular, it is what we educational researchers do. In my estimation, we have the hardest-to-do science of them all! We do our science under conditions that physical scientists find intolerable. We face particular problems and must deal with local conditions that limit generalizations and theory building-problems that are different from those faced by the easier-to-do sciences …

Context-MAtters_Blog_Chip_180321_093400Huge context effects cause scientists great trouble in trying to understand school life … A science that must always be sure the myriad particulars are well understood is harder to build than a science that can focus on the regularities of nature across contexts …

Doing science and implementing scientific findings are so difficult in education because humans in schools are embedded in complex and changing networks of social interaction. The participants in those networks have variable power to affect each other from day to day, and the ordinary events of life (a sick child, a messy divorce, a passionate love affair, migraine headaches, hot flashes, a birthday party, alcohol abuse, a new principal, a new child in the classroom, rain that keeps the children from a recess outside the school building) all affect doing science in school settings by limiting the generalizability of educational research findings. Compared to designing bridges and circuits or splitting either atoms or genes, the science to help change schools and classrooms is harder to do because context cannot be controlled.

David Berliner

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