Economic models are getting more and more sophisticated — and totally useless

18 January, 2017 at 18:27 | Posted in Economics | Leave a comment

 

Those of us in the economics community who are impolite enough to dare question the preferred methods and models applied in mainstream economics, are as a rule met with disapproval. But although people seem to get very agitated and upset by the critique — just read the commentaries on this blog if you don’t believe me — defenders of “received theory” always say that the critique is “nothing new”, that they have always been “well aware” of the problems, and so on, and so on.

So, for the benefit of all mindless practitioners of mainstream economic modeling — who defend mainstream economics with arguments like “the speed with which macro has put finance at the center of its theories of the business cycle has been nothing less than stunning,” and re the patently ridiculous representative-agent modeling, maintain that there “have been efforts to put heterogeneity into big DSGE-type models” but that these models “didn’t get quite as far, because this kind of thing is very technically difficult to model,” and as for rational expectations admit that “so far, macroeconomists are still very timid about abandoning this pillar of the Lucas/Prescott Revolution,” but that “there’s no clear alternative” — and who don’t want to be disturbed in their doings, eminent mathematical statistician David Freedman has put together a very practical list of vacuous responses to criticism that can be freely used to save your peace of mind:

We know all that. Nothing is perfect … The assumptions are reasonable. The assumptions don’t matter. The assumptios are conservative. You can’t prove the assumptions are wrong. The biases will cancel. We can model the biases. We’re only doing what evereybody else does. Now we use more sophisticated techniques. If we don’t do it, someone else will. What would you do? The decision-maker has to be better off with us than without us … The models aren’t totally useless. You have to do the best you can with the data. You have to make assumptions in order to make progress. You have to give the models the benefit of the doubt. Where’s the harm?

Calvo pricing — a ‘New Keynesian’ fairytale

16 January, 2017 at 18:50 | Posted in Economics | Leave a comment

pinnocThus your standard New Keynesian model will use Calvo pricing and model the current inflation rate as tightly coupled to the present value of expected future output gaps. Is this a requirement anyone really wants to put on the model intended to help us understand the world that actually exists out there? Thus your standard New Keynesian model will calculate the expected path of consumption as the solution to some Euler equation plus an intertemporal budget constraint, with current wealth and the projected real interest rate path as the only factors that matter. This is fine if you want to demonstrate that the model can produce macroeconomic pathologies. But is it a not-stupid thing to do if you want your model to fit reality?

I remember attending the first lecture in Tom Sargent’s evening macroeconomics class back when I was in undergraduate: very smart man from whom I have learned the enormous amount, and well deserving his Nobel Prize. But…

He said … we were going to build a rigorous, micro founded model of the demand for money: We would assume that everyone lived for two periods, worked in the first period when they were young and sold what they produced to the old, held money as they aged, and then when they were old use their money to buy the goods newly produced by the new generation of young. Tom called this “microfoundations” and thought it gave powerful insights into the demand for money that you could not get from money-in-the-utility-function models.

I thought that it was a just-so story, and that whatever insights it purchased for you were probably not things you really wanted to buy. I thought it was dangerous to presume that you understood something because you had “microfoundations” when those microfoundations were wrong. After all, Ptolemaic astronomy had microfoundations: Mercury moved more rapidly than Saturn because the Angel of Mercury left his wings more rapidly than the Angel of Saturn and because Mercury was lighter than Saturn…

Brad DeLong

Brad DeLong is of course absolutely right here, and one could only wish that other ‘New Keynesian’ macroeconomists would take a similar critical approach to their own modeling endeavours …

A philosophical look at economics

15 January, 2017 at 13:57 | Posted in Economics | 2 Comments

pe_picOwing to the elegance of explanations in natural science, scientists in other disciplines are likely to be tempted to emulate this success. While that is a good thing in the sense of striving to observe the four criteria or coherence, correspondence, practicality and economy, it is not a good thing if scientists doing life or social science become unmindful of the limitations imposed by the subject matter of their discipline. The result will be application of inappropriate methodology and exaggerated claims.

Science is generally divided into natural, life, and social science based on subject matter. Science in general aims at causal understanding of a universe in which natural, life and social sciences are aspects of various phenomena.

Consilience is also a requirement in doing science. Scientific theories are expected to corroborate other and not contradict each other in that science aims at a general explanation of “reality.”

As a philosopher looking at economics as an amateur, it appears to me that many economists are careless about applying the above criteria and therefore overstate their claims and likely overestimate their knowledge. as being scientific instead of speculative, and objective rather than interested.

This is even before getting into measurement and historical issues. There really needs to be more attention paid to philosophy of science, philosophy of social science in economics and much more work is needed in philosophy (foundations) of economics, which is underdeveloped since so few people have contributed to it. Indeed, a lot of what passes for philosophy of economics now is mostly ideology. Yet, conventional economists claim that methodological questions are settled. NOT!

Tom Hickey

Economics — more like phrenology than physics

13 January, 2017 at 16:38 | Posted in Economics | 3 Comments

1760a-petrus-camper-facial-angle-eugenics-paul-d-stewartWhat made phrenology so popular was what also made economics so popular at the time: it gave a rationale for a society based on Progress and also provided a blueprint for how this could be achieved. The phrenological doctrine, being so vague in its pronouncements, was highly malleable and could be used to justify whatever those in power needed justifying. So, for example, in 19th century England phrenology was used to justify laissez faire economic policies by emphasising unequal natural capacities amongst the population while in early 20th century Belgian Rwanda it was used to justify the supposed superiority of the Tutsis over the Hutus.

In my book The Reformation in Economics I take the position that modern economics is more similar to phrenology than it is to, say, physics. This is not at all surprising as it grew up in the same era and out of remarkably similar ideas. But what is surprising is that this is not widely noticed today. What is most tragic, however, is that there is much in economics that can and should be salvaged. While these positive aspects of economics probably do not deserve the title of ‘science’ they at least provide us with a rational toolkit that can be used to improve political and economic governance in our societies.

Philip Pilkington

Why ‘sunspots’ matter

12 January, 2017 at 23:42 | Posted in Economics | 1 Comment

My recent research with Carine Nourry and Alain Venditti argues that while there are strong reasons for believing there are no free lunches left uneaten by bonus-hungry market participants, there are really no reasons for believing that this will lead to Pareto efficiency, except, perhaps, by chance …

sunspot_numbers

In our model environment, booms and crashes occur simply as a consequence of the animal spirits of market participants. Why should we care if there are big movements in the asset markets? After all, the borrowers and lenders are rational and they have made bets with each other in full knowledge that these large asset movements might occur.

•The problem is that the next generation is unable to insure against swings in wealth that have a big influence on their lives.

Steve Davis and Till von Wachter (2011) have shown that the present value of lifetime income of new entrants to the labour market can differ substantially depending on whether their first job occurs in a boom or a recession. In our model, the lifetime income of the young can differ by as much as 20% across booms and slumps.

Given the choice, the young agents in our model would prefer to avoid the risk of a 20% variation in lifetime wealth. There is a feasible way of allocating resources that would insure them against this risk, but financial markets cannot achieve this allocation, except by chance. The inability of our children to trade in prenatal financial markets is sufficient to invalidate the first welfare theorem of economics.

In short, sunspots matter. And they matter in a big way.

Roger Farmer

Yes indeed. David Cass’ and Karl Shell’s ‘sunspots’ show that financial markets are far from Pareto efficient. And the day Roger Farmer is prepared to drop his residual mainstream infatuation with models building on assumptions of ‘complete financial markets,’ rational expectations, and households planning for infinite futures, his thought-provoking critique of mainstream economics will be even more forceful …

Reality virus strikes economics!

12 January, 2017 at 19:26 | Posted in Economics | Leave a comment

The WHO today warned of a virulent new virus affecting vulnerable groups in the Mid-West and Eastern USA. The outbreak, which began in the Mid-West’s extensive Great Lakes ‘Freshwater’ river system, has recently jumped the ‘Saltwater’ barrier, meaning that the entire population of its target species – ‘Mainstream’ economists – is now at risk.

roke_cover-thumbSpeaking on behalf of the WHO, Dr Cahuc explained that the virus works by turning off the one genetic marker that distinguishes this species from the rest of its genus, the Human Race. This is the so-called ‘Milton’ gene (Friedman 1953), which goes dormant in other Humans as they pass through puberty. Its inactivity reduces their imaginative capacity, making it impossible for them to continue believing in such endearing infantile fantasies as the Tooth Fairy and Santa Claus. While regrettable, this drop in imagination is necessary to prepare Humans for the adult phase of their existence …

The new virus – named ‘Reality’ – de-activates the Milton gene once more. ‘Consequently’, Dr Cahuc warned, ‘the very beliefs that define this unique species are at risk. Unless we are very careful, it may become extinct!’.

Unfortunately, there is as yet no known cure to this virus. ‘The WHO therefore recommends complete avoidance of “Reality” as the only effective strategy for those wishing to remain as Mainstream Economists’, Dr Cahuc concluded.

However, this strategy is made extremely difficult by one cunning characteristic of the Reality virus: after an initial phase of disorientation and distress, its sufferers begin to experience pleasure, and actually want to pass the virus on to others. ‘Its transmission mechanism is a particularly insidious aspect of this disease’, Dr Cahuc lamented.

Steve Keen

New Keynesianism — neither new nor Keynesian

11 January, 2017 at 21:32 | Posted in Economics | Leave a comment

Maintaining that economics is a science in the ‘true knowledge’ business, I remain a skeptic of the pretences and aspirations of ‘New Keynesian’ macroeconomics. So far, I cannot really see that it has yielded very much in terms of realist and relevant economic knowledge. And there’s nothing new or Keynesian about it.

counterfeit‘New Keynesianism’ doesn’t have its roots in Keynes. It has its intellectual roots in Paul Samuelson’s ill-founded ‘neoclassical synthesis’ project, whereby he thought he could save the ‘classical’ view of the market economy as a (long run) self-regulating market clearing equilibrium mechanism, by adding some (short run) frictions and rigidities in the form of sticky wages and prices.

But — putting a sticky-price lipstick on the ‘classical’ pig sure won’t do. The ‘New Keynesian’ pig is still neither Keynesian nor new.

The rather one-sided emphasis of usefulness and its concomitant instrumentalist justification cannot hide that ‘New Keynesians’ cannot give supportive evidence for their considering it fruitful to analyze macroeconomic structures and events as the aggregated result of optimizing representative actors. After having analyzed some of its ontological and epistemological foundations, yours truly cannot but conclude that ‘New Keynesian’ macroeconomics on the whole has not delivered anything else than ‘as if’ unreal and irrelevant models.

The purported strength of New Classical and ‘New Keynesian’ macroeconomics is that they have firm anchorage in preference-based microeconomics, and especially the decisions taken by inter-temporal utility maximizing ‘forward-looking’ individuals.

To some of us, however, this has come at too high a price. The almost quasi-religious insistence that macroeconomics has to have microfoundations – without ever presenting neither ontological nor epistemological justifications for this claim – has put a blind eye to the weakness of the whole enterprise of trying to depict a complex economy based on an all-embracing representative actor equipped with superhuman knowledge, forecasting abilities and forward-looking rational expectations. It is as if – after having swallowed the sour grapes of the Sonnenschein-Mantel-Debreu-theorem – these economists want to resurrect the omniscient Walrasian auctioneer in the form of all-knowing representative actors equipped with rational expectations and assumed to somehow know the true structure of our model of the world.

And then, of course, there is that weird view on unemployment that makes you wonder on which planet those ‘New Keynesians’ live …

A true Post Keynesian

11 January, 2017 at 18:45 | Posted in Economics | 1 Comment

keynes3But these more recent writers like their predecessors were still dealing with a system in which the amount of the factors employed was given and the other relevant facts were known more or less for certain. This does not mean that they were dealing with a system in which change was ruled out, or even one in which the disappointment of expectation was ruled out. But at any given time facts and expectations were assumed to be given in a definite and calculable form; and risks, of which, tho admitted, not much notice was taken, were supposed to be capable of an exact actuarial computation. The calculus of probability, tho mention of it was kept in the background, was supposed to be capable of reducing uncertainty to the same calculable status as that of certainty itself …

Thus the fact that our knowledge of the future is fluctuating, vague and uncertain, renders Wealth a peculiarly unsuitable subject for the methods of the classical economic theory.

John Maynard Keynes

And this emphasis on the importance of uncertainty is not even mentioned in IS-LM ‘New Keynesianism’ …

Unemployment delusion

10 January, 2017 at 21:31 | 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 dynamic stochastic general equilibrium models do not incorporate such a basic fact of reality as involuntary unemployment. Of course, working with microfounded representative agent models, this should 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 an obvious and sad fact of the world that not all unemployment is voluntary. But obviously not so to New Classical and ‘New Keynesian’ economists.

Top 10 economics blog posts

10 January, 2017 at 13:05 | Posted in Economics | Leave a comment

top-10-retail-news-thumb-610xauto-79997-600x240

  1. Dumb and dumber in modern macroeconomics
  2. Why Paul Krugman is no real Keynesian
  3. Dani Rodrik’s blind spot
  4. Robert Lucas, rational expectations, and the understanding of business cycles
  5. The blatant absence of empirical fit of macroeconomic models
  6. Non-ergodic economics, expected utility and the Kelly criterion
  7. The real debt problem
  8. Is macroeconomics for real?
  9. Please say after me – Sonnenschein-Mantel-Debreu
  10. Probaility and economics
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