Archive

Author Archive

Do models make economics a science?

September 22, 2019 4 comments

from Lars Syll

Well, if we are to believe most mainstream economists, models are what make economics a science.

economists_do_it_with_models_economics_humor_keychain-re3ab669c9dd84be1806dc76325a18fd0_x7j3z_8byvr_425In a Journal of Economic Literature review of Dani Rodrik’s Economics Rules, renowned game theorist Ariel Rubinstein discusses Rodrik’s justifications for the view that “models make economics a science.” Although Rubinstein has some doubts about those justifications — models are not indispensable for telling good stories or clarifying things in general; logical consistency does not determine whether economic models are right or wrong; and being able to expand our set of ‘plausible explanations’ doesn’t make economics more of a science than good fiction does — he still largely subscribes to the scientific image of economics as a result of using formal models that help us achieve ‘clarity and consistency’.

There’s much in the review I like — Rubinstein shows a commendable scepticism on the prevailing excessive mathematization​ of economics, and he is much more in favour of a pluralist teaching of economics than most other mainstream economists — but on the core question, “the model is the message,” I beg to differ with the view put forward by both Rodrik and Rubinstein. Read more…

Nordhaus dangerous gamble for humanity’s future

September 21, 2019 7 comments

from Lars Syll

Nordhaus’s transgressions are immense. His ‘damage function’ which he uses to estimate global warming damage is incorrect and uses data that has nothing to do with climate change. Despite this, the Intergovernmental Panel on Climate Change (IPCC) uses his model to advise governments about the economic impact of global warming.

Thermometer graphicsNordhaus and other mainstream climate economists certainly have a lot to answer for. Their thinking has seriously delayed action to avert damage done from climate change.

The central problem with Nordhaus’s model is the “damage function”, which is a mathematical fiction that has little to do the real world. Using a spurious method, he calculates that 2°C of warming will only reduce global economic output – GDP – by 0.9 percent, and 4°C would cut GDP by 3.6 percent.

These are trivial changes. If it were true, there would be little to worry about. This is the reason that Nordhaus has repeatedly argued that from the point of view of economic rationality an “optimal” path would be 3.5°C of warming above preindustrial levels. Read more…

The lack of positive results in econometrics

September 17, 2019 3 comments

from Lars Syll

For the sake of balancing the overly rosy picture of econometric achievements given in the usual econometrics textbooks today, it may be interesting to see how Trygve Haavelmo — with the completion (in 1958) of the twenty-fifth volume of Econometrica — assessed the role of econometrics in the advancement of economics.

Haavelmo intro 2We have found certain general principles which would seem to make good sense. Essentially, these principles are based on the reasonable idea that, if an economic model is in fact “correct” or “true,” we can say something a priori about the way in which the data emerging from it must behave. We can say something, a priori, about whether it is theoretically possible to estimate the parameters involved. And we can decide, a priori, what the proper estimation procedure should be … But the concrete results of these efforts have often been a seemingly lower degree of accuracy of the would-be economic laws (i.e., larger residuals), or coefficients that seem a priori less reasonable than those obtained by using cruder or clearly inconsistent methods. Read more…

Central bank independence — institutionalizing monetary handcuffs

September 14, 2019 7 comments

from Lars Syll

hqb813cpgmtyImposing a hard target can bind the central bank, but the government must then act on failures to hit the target. Why would it if it is self-interested? If it does, that amounts to saying it is not selfish, which undermines the argument that independence is needed. The same argument can be used to deconstruct independence itself. Suppose independence is a solution to time inconsistency. Why would a selfish politician ever agree to independence in the first place? If they did, that would be tantamount to saying they are not selfish, in which case independence is not needed. In other words, only non-self-interested politicians choose independence, making independence redundant …

Even if the banker is honest, there still remains the fundamental question of why would selfish politicians go against their own interests and appoint a conservative independent central banker? Doing so is tantamount to proving they are not selfish, in which case there is no need for an independent central bank. Read more…

Kitchen sink econometrics

September 11, 2019 11 comments

from Lars Syll

When I present this argument … one or more scholars say, “But shouldn’t I control for everything I can in my regressions? If not, aren’t my coefficients biased due to excluded variables?” This argument is not as persuasive as it may seem initially. First of all, if what you are doing is misspecified already, then adding or excluding other variables has no tendency to make things consistently better or worse … The excluded variable argument only works if you are sure your specification is precisely correct with all variables included. But no one can know that with more than a handful of explanatory variables.
piled-up-dishes-in-kitchen-sinkStill more importantly, big, mushy linear regression and probit equations seem to need a great many control variables precisely because they are jamming together all sorts of observations that do not belong together. Countries, wars, racial categories, religious preferences, education levels, and other variables that change people’s coefficients are “controlled” with dummy variables that are completely inadequate to modeling their effects. The result is a long list of independent variables, a jumbled bag of nearly unrelated observations, and often a hopelessly bad specification with meaningless (but statistically significant with several asterisks!) results. Read more…

Necessary inventions …

September 10, 2019 25 comments

from Lars Syll

pointless-inventions1

The quasi-peaceable gentleman of leisure, then, not only consumes of the staff of life beyond the minimum required for subsistence and physical efficiency, but his consumption also undergoes a specialisation as regards the quality of the goods consumed. He consumes freely and of the best, in food, drink, narcotics, shelter, services, ornaments, apparel, weapons and accoutrements, amusements, amulets, and idols or divinities.

Thorstein Veblen

The pretense-of-knowledge syndrome in economics

September 8, 2019 9 comments

from Lars Syll

What does concern me about my discipline … is that its current core — by which I mainly mean the so-called dynamic stochastic general equilibrium approach — has become so mesmerized with its own internal logic that it has begun to confuse the precision it has achieved about its own world with the precision that it has about the real one …

While it often makes sense to assume rational expectations for a limited application to isolate a particular mechanism that is distinct from the role of expectations formation, this assumption no longer makes sense once we assemble the whole model. Agents could be fully rational with respect to their local environments and everyday activities, but they are most probably nearly clueless with respect to the statistics about which current macroeconomic models expect them to have full information and rational information. Read more…

A guide to econometrics

September 6, 2019 17 comments

from Lars Syll

kennedyguide1. Thou shalt use common sense and economic theory.
2. Thou shalt ask the right question.
3. Thou shalt know the context.
4. Thou shalt inspect the data.
5. Thou shalt not worship complexity.
6. Thou shalt look long and hard at thy results.
7. Thou shalt beware the costs of data mining.
8. Thou shalt be willing to compromise.
9. Thou shalt not confuse statistical significance with substance.
10. Thou shalt confess in the presence of sensitivity.

On the irrelevance of economics

September 5, 2019 59 comments

from Lars Syll

I believe that as an economic theorist, I have very little to say about the real world and that there are very few models in economic theory that can be used to provide serious advice. However, economic theory has real effects. I cannot ignore the fact that our work as teachers and researchers influences students’ minds and does so in a way with which I am not comfortable. Can we find a way to be relevant without being charlatans?

stunAs economic theorists, we organize our thoughts using what we call models.
The word “model” sounds more scientific than “fable” or “fairy tale” although I do not see much difference between them. The author of a fable draws a parallel to a situation in real life. He has some moral he wishes to impart to the reader … Being something between fantasy and reality, a fable is free of extraneous details and annoying diversions …

We do exactly the same thing in economic theory … We perform thought exercises that are only loosely connected to reality and that have been stripped of most of their real-life characteristics.

Ariel Rubinstein

Why monetary policies are impotent

September 4, 2019 3 comments

from Lars Syll

Even if interest-rate cuts at all points proximately increase demand, there are substantial grounds for concern if this effect is weak. It may be that any short-run demand benefit is offset by the adverse effects of lower rates on subsequent performance …

commercial illustratorFrom a macro perspective, low interest rates promote leverage and asset bubbles by reducing borrowing costs and discount factors, and encouraging investors to reach for yield. Almost every account of the 2008 financial crisis assigns at least some role to the consequences of the very low interest rates that prevailed in the early 2000s. More broadly, students of bubbles, from the economic historian Charles Kindleberger onward, always emphasize the role of easy money and overly ample liquidity.

From a micro perspective, low rates undermine financial intermediaries’ health by reducing their profitability, impede the efficient allocation of capital by enabling even the weakest firms to meet debt-service obligations, and may also inhibit competition by favoring incumbent firms …

In moving toward the secular stagnation view, we have come to agree with the point long stressed by writers in the post-Keynesian (or, perhaps more accurately, original Keynesian) tradition: the role of particular frictions and rigidities in underpinning economic fluctuations should be de-emphasized relative to a more fundamental lack of aggregate demand …

What is needed are admissions of impotence, in order to spur efforts by governments to promote demand through fiscal policies and other means.

Lawrence Summers & Anna Stansbury

New ‘Keynesians’ — like Paul Krugman and Simon Wren-Lewis — have Read more…

Cherry-picking economic models

September 2, 2019 56 comments

from Lars Syll

How would you react if a renowned physicist, say, ​Richard Feynman, was telling you that sometimes force is proportional to acceleration and at other times it is proportional to acceleration squared?

cartoon-hand-picking-cherry-24380737I guess you would be unimpressed. But actually, what most mainstream economists do amounts to the same strange thing when it comes to theory development and model modification.

In mainstream economic theory,​ preferences are standardly expressed in the form of a utility function. But although the expected utility theory has been known for a long time to be both theoretically and descriptively inadequate, mainstream economists all over the world gladly continue to use it, as though its deficiencies were unknown or unheard of.

What most mainstream economists try to do in face of the obvious theoretical and behavioural inadequacies of the expected utility theory, is to marginally mend it. But that cannot be the right attitude when facing scientific anomalies. When models are plainly wrong, you’d better replace them! Instead of mending the broken pieces it would be much better to concentrate on developing descriptively accurate models of choice under uncertainty. Read more…

Modern macroeconomics

August 29, 2019 18 comments

from Lars Syll

There is a purist streak in economics that wants everything to follow from asumming things like ‘rationality’ and ‘equilibrium.’ That purist streak has given birth to a kind ‘deductivist blindness’ of mainstream economics, something that also to a larger extent explains why it contributes to causing economic crises rather than to solving them. But where does this ‘deductivist blindness’ of mainstream economics come from? To answer that question we have to examine the methodology of mainstream economics.

The insistence on constructing models showing the certainty of logical entailment has been central in the development of mainstream economics. Insisting on formalistic (mathematical) modeling has more or less forced the economist to give upon on realism and substitute axiomatics for real world relevance. The price paid for the illusory rigour and precision has been monumentally high.

Real business cycle theory (RBC) is one of the theories that has put macroeconomics on a path of intellectual regress for three decades now. And although there are many kinds of useless ‘post-real’economics held in high regard within mainstream economics establishment today, few — if any — are less deserved than real business cycle theory. Read more…

What — if anything — do p-values test?

August 27, 2019 9 comments

from Lars Syll

pvUnless enforced by study design and execution, statistical assumptions usually have no external justification; they may even be quite implausible. As result, one often sees attempts to justify specific assumptions with statistical tests, in the belief that a high p-value or ‘‘nonsignificance’’ licenses the assumption and a low p-value refutes it. Such focused testing is based on a meta-assumption that every other assumption used to derive the p-value is correct, which is a poor judgment when some of those other assumptions are uncertain. In that case (and in general) one should recognize that the p-value is simultaneously testing all the assumptions used to compute it – in particular, a null p-value actually tests the entire model, not just the stated hypothesis or assumption it is presumed to test.

Sander Greenland

All science entails human judgement, and using statistical models doesn’t relieve us of that necessity. Working with misspecified models, the scientific value of significance testing is actually zero —  even though you’re making valid statistical inferences! Statistical models and concomitant significance tests are no substitutes for doing real science. Read more…

Econometrics and the problem of unjustified assumptions

August 25, 2019 15 comments

from Lars Syll

There seems to be a pervasive human aversion to uncertainty, and one way to reduce feelings of uncertainty is to invest faith in deduction as a sufficient guide to truth. Unfortunately, such faith is as logically unjustified as any religious creed, since a deduction produces certainty about the real world only when its assumptions about the real world are certain …

economUnfortunately, assumption uncertainty reduces the status of deductions and statistical computations to exercises in hypothetical reasoning – they provide best-case scenarios of what we could infer from specific data (which are assumed to have only specific, known problems). Even more unfortunate, however, is that this exercise is deceptive to the extent it ignores or misrepresents available information, and makes hidden assumptions that are unsupported by data …

Econometrics supplies dramatic cautionary examples in which complex modellin​g has failed miserably in important applications …

Sander Greenland

Yes, indeed, econometrics fails miserably over and over again.

One reason why it does, is that Read more…

Marginal productivity theory — a dangerous thought virus

August 23, 2019 19 comments

from Lars Syll

execThe marginal productivity theory of income distribution was born a little over a century ago. Its principle creator, John Bates Clark, was explicit that his theory was about ideology and not science. Clark wanted show that in capitalist societies, everyone got what they produced, and hence all was fair:

“It is the purpose of this work to show that the distribution of the income of society is controlled by a natural law, and that this law, if it worked without friction, would give to every agent of production the amount of wealth which that agent creates. (John Bates Clark in The Distribution of Wealth)”

Clark was also explicit about why his theory was needed. The stability of the capitalist order was at stake! Here’s Clark again:

“The welfare of the laboring classes depends on whether they get much or little; but their attitude toward other classes—and, therefore, the stability of the social state—depends chiefly on the question, whether the amount that they get, be it large or small, is what they produce. If they create a small amount of wealth and get the whole of it, they may not seek to revolutionize society; but if it were to appear that they produce an ample amount and get only a part of it, many of them would become revolutionists, and all would have the right to do so. (John Bates Clark in The Distribution of Wealth)”

So the neoclassical theory of income distribution was born as an ideological response to Marxism. According to Marx, capitalists extract a surplus from workers, and so workers get less than what they deserve. Clark’s marginal productivity theory aimed to show that this was not true. Both capitalists and workers, Clark claimed, got what they deserved.

The message of Clark’s theory is simple: workers need to stay in their place. They already earn what they produce, so they have no right to demand more.

Blair Fix

Read more…

Wren-Lewis trying to cope with ideology

August 22, 2019 9 comments

from Lars Syll

Simon Wren-Lewis has also commented on the study by Mohsen Javdani and Ha-Joon Chang — on economics and ideology — that I wrote about earlier today. Says Wren-Lewis:

scI also, from my own experience, want to suggest that in their formal discourse (seminars, refereeing etc) academic economists normally pretend that this ideological bias does not exist. I cannot recall anyone in any seminar saying something like ‘you only assume that because of your ideology/politics’. This has one huge advantage. It means that academic analysis is judged (on the surface at least) on its merits, and not on the basis of the ideology of those involved.

The danger of doing the opposite should be obvious. Your view on the theoretical and empirical validity of an academic paper or study may become dependent on the ideology or politics of the author or the political implications of the results rather than its scientific merits. Having said that, there are many people who argue that economics is just a form of politics and economists should stop pretending otherwise. I disagree. Economics can only be called a science because it embraces the scientific method. The moment evidence is routinely ignored by academics because it does not help some political project economics stops being the science it undoubtedly is.

Quite frankly I have to admit to being at a loss here. Of course, you never hear anyone at our seminars telling the lecturer that the assumptions on which his models are built are only made for ideological reasons. Read more…

We need more redistribution

August 20, 2019 16 comments

from Lars Syll

Income inequality as measured by the Gini coefficient rose by about 36% in the 1980s under Thatcher, but the real story is the share of income that goes to people at the very top:

According to Greg Mankiw … in the United States the 1%’s share of total income, excluding capital gains, rose from about 8 percent in 1973 to 17 percent in 2010. Between 2010 and 2015 it’s risen from 17% to 22%!!

inequalityIt’s incredibly concentrated even among the super-rich. The top 0.01%’s share of national income – this is just 16,000 people in a country of 330 million – rose from 0.5% in 1973 to 3.3% in 2010 to 5% in 2015. Their share of income quadrupled in just 35 years …

Just giving people money is fine if you don’t mind them playing video games all day – but many people themselves would tell you that they don’t have the willpower to go back to school or find new work, even if they could do so in theory.

There’s a big role for government to direct investment towards these places, using the money we’ve taken from the winners from globalisation, either to support private industry or just set up our own industries to employ people the private sector won’t …

The super-rich are eating a bigger and bigger slice of the pie, for no good reason, and there are lots of things we could use that money for to make ordinary people’s lives better.

Sam Bowman

Mainstream economics textbooks usually refer to the interrelationship between technological development and education as the main causal force behind increased inequality. Read more…

Economics and ideology

August 19, 2019 9 comments

from Lars Syll

Mainstream (neoclassical) economics has always put a strong emphasis on the positivist conception of the discipline, characterizing economists and their views as objective, unbiased, and non-ideological …

Ronald_Reagan_televised_address_from_the_Oval_Office,_outlining_plan_for_Tax_Reduction_Legislation_July_1981Acknowledging that ideology resides quite comfortably in our economics departments would have huge intellectual implications, both theoretical and practical. In spite (or because?) of that, the matter has never been directly subjected to empirical scrutiny.

In a recent study, we do just that. Using a well-known experimental “deception” technique embedded in an online survey that involves just over 2400 economists from 19 countries, we fictitiously attribute the source of 15 quotations to famous economists of different leanings. In other words, all participants received identical statements to agree or disagree with, but source attribution was randomly changed without the participants’ knowledge. The experiment provides clear evidence that ideological bias strongly influences the ideas and judgements of economists. More specifically, we find that changing source attributions from mainstream to less-/non-mainstream figures significantly reduces the respondents’ reported agreement with statements. Interestingly, this contradicts the image economists have of themselves, with 82% of participants reporting that in evaluating a statement one should only pay attention to its content and not to the views of its author … Read more…

Statistics and mathematics — not very helpful for understanding economies

August 16, 2019 11 comments

from Lars Syll

Statistical science is not really very helpful for understanding or forecasting complex evolving self-healing organic ambiguous social systems – economies, in other words.

leamer1 zoomedA statistician may have done the programming, but when you press a button on a computer keyboard and ask the computer to find some good patterns, better get clear a sad fact: computers do not think. They do exactly what the programmer told them to do and nothing more. They look for the patterns that we tell them to look for, those and nothing more. When we turn to the computer for advice, we are only talking to ourselves …

Mathematical analysis works great to decide which horse wins, if we are completely confident which horses are in the race, but it breaks down when we are not sure. In experimental settings, the set of alternative models can often be well agreed on, but with nonexperimental economics data, the set of models is subject to enormous disagreements. You disagree with your model made yesterday, and I disagree with your model today. Mathematics does not help much resolve our internal intellectual disagreements.

Ed Leamer

Indeed. As social researchers we should never equate science with mathematics and statistical calculation. Read more…

No reality, please. We’re economists!

August 14, 2019 20 comments

from Lars Syll

Mathematics, especially through the work of David Hilbert, became increasingly viewed as a discipline properly concerned with providing a pool of frameworks for possible realities. No longer was mathematics seen as the language of (non-social) nature, abstracted from the study of the latter. Rather, it was conceived as a practice concerned with formulating systems comprising sets of axioms and their deductive consequences, with these systems in effect taking on a life of their own. The task of finding applications was henceforth regarded as being of secondary importance at best, and not of immediate concern.

ffullbrookThis emergence of the axiomatic method removed at a stroke various hitherto insurmountable constraints facing those who would mathematise the discipline of economics. Researchers involved with mathematical projects in economics could, for the time being at least, postpone the day of interpreting their preferred axioms and assumptions. There was no longer any need to seek the blessing of mathematicians and physicists or of other economists who might insist that the relevance of metaphors and analogies be established at the outset. In particular it was no longer regarded as necessary, or even relevant, to economic model construction to consider the nature of social reality, at least for the time being …

The result was that in due course deductivism in economics, through morphing into mathematical deductivism on the back of developments within the discipline of mathematics, came to acquire a new lease of life, with practitioners (once more) potentially oblivious to any inconsistency between the ontological presuppositions of adopting a mathematical modelling emphasis and the nature of social reality. The consequent rise of mathematical deductivism has culminated in the situation we find today.

Tony Lawson

I think the ‘confidence’ mainstream economists have in their own theories and models, basically is a question of methodology. Read more…