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The danger of teaching the wrong thing all too well

September 12, 2022 Leave a comment

from Lars Syll

It is well known that even experienced scientists routinely misinterpret p-values in all sorts of ways, including confusion of statistical and practical significance, treating non-rejection as acceptance of the null hypothesis, and interpreting the p-value as some sort of replication probability or as the posterior probability that the null hypothesis is true …

servicemanIt is shocking that these errors seem so hard-wired into statisticians’ thinking, and this suggests that our profession really needs to look at how it teaches the interpretation of statistical inferences. The problem does not seem just to be technical misunderstandings; rather, statistical analysis is being asked to do something that it simply can’t do, to bring out a signal from any data, no matter how noisy. We suspect that, to make progress in pedagogy, statisticians will have to give up some of the claims we have implicitly been making about the effectiveness of our methods …

It would be nice if the statistics profession was offering a good solution to the significance testing problem and we just needed to convey it more clearly. But, no, … many statisticians misunderstand the core ideas too. It might be a good idea for other reasons to recommend that students take more statistics classes—but this won’t solve the problems if textbooks point in the wrong direction and instructors don’t understand what they are teaching. To put it another way, it’s not that we’re teaching the right thing poorly; unfortunately, we’ve been teaching the wrong thing all too well.

Andrew Gelman & John Carlin

Teaching both statistics and economics, yours truly can’t but notice that Read more…

Econometric FUQs

September 5, 2022 3 comments

from Lars Syll

Mostly Harmless EconometricsIf you can’t devise an experiment that answers your question in a world where anything goes, then the odds of generating useful results with a modest budget and nonexperimental survey data seem pretty slim. The description of an ideal experiment also helps you formulate causal questions precisely. The mechanics of an ideal experiment highlight the forces you’d like to manipulate and the factors you’d like to hold constant.

Research questions that cannot be answered by any experiment are FUQs: fundamentally unidentified questions.

One of the limitations of economics is the restricted possibility to perform experiments, forcing it to mainly rely on observational studies for knowledge of real-world economies.

But still — the idea of performing laboratory experiments holds a firm grip on our wish to discover (causal) relationships between economic ‘variables.’If we only could isolate and manipulate variables in controlled environments, we would probably find ourselves in a situation where we with greater ‘rigour’ and ‘precision’ could describe, predict, or explain economic happenings in terms of ‘structural’ causes, ‘parameter’ values of relevant variables, and economic ‘laws.’ Read more…

Economics as ideology

August 30, 2022 3 comments

from Lars Syll

Study proves trickle-down didn't trickle | PoliticsNCTax cuts for the wealthy were supposed to stimulate growth and make everyone better off. There was dispute about this within the profession, but there were also many economists who provided intellectual support for the claim that tax cuts will create growth and widespread prosperity. The evidence from the Bush and Reagan tax cuts does not support this claim, but it is still made by some economists and this gives those who are serving wealthy interests or who want to force government to shrink by starving it of revenue the cover they need for their arguments …

We do need more humility about what we do and do not know, more willingness to change our minds when the evidence disagrees with our favorite theoretical model, and the willingness to acknowledge disagreement within the profession. But most of all we need to take a strong stand against those inside and outside the profession who misuse economic theory and empirical results for political and ideological purposes.

Mark Thoma

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. But that does not necessarily mean — whether on the surface or not — that academic analysis is judged on its merits. What it means is that we have a catechism that no one dares to question. Read more…

Science and crossword solving

August 23, 2022 2 comments

from Lars Syll

Evidence and Inquiry: Towards Reconstruction in Epistemology by Susan Haack  - Hardcover - Reprint - 1994 - from Common Crow Books (SKU: B54435)The model is not . . . how one determines the soundness or otherwise of a mathematical proof; it is, rather, how one determines the reasonableness or otherwise of entries in a crossword puzzle. . . . The crossword model permits pervasive mutual support, rather than, like the model of a mathematical proof, encouraging an essentially one-directional conception. . . . How reasonable one’s confidence is that a certain entry in a crossword is correct depends on: how much support is given to this entry by the clue and any intersecting entries that have already been filled in; how reasonable, independently of the entry in question, one’s confidence is that those other already filled-in entries are correct; and how many of the intersecting entries have been filled in.

Yours truly — an avid crossword solver himself — can’t but agree.

In inference to the best explanation, we start with a body of (purported) data/facts/evidence and search for explanations that can account for these data/facts/evidence. Having the best explanation means that you, given the context-dependent background assumptions, have a satisfactory explanation that can explain the evidence better than any other competing explanation — and so it is reasonable to consider the hypothesis to be true. Even if we (inevitably) do not have deductive certainty, our reasoning gives us a license to consider our belief in the hypothesis as reasonable.  Read more…

Econometrics — the danger of calling your pet cat dog

August 20, 2022 3 comments

from Lars Syll

The assumption of additivity and linearity means that the outcome variable is, in reality, linearly related to any predictors … and that if you have several predictors then their combined effect is best described by adding their effects together …

catdogThis assumption is the most important because if it is not true then even if all other assumptions are met, your model is invalid because you have described it incorrectly. It’s a bit like calling your pet cat a dog: you can try to get it to go in a kennel, or to fetch sticks, or to sit when you tell it to, but don’t be surprised when its behaviour isn’t what you expect because even though you’ve called it a dog, it is in fact a cat. Similarly, if you have described your statistical model inaccurately it won’t behave itself and there’s no point in interpreting its parameter estimates or worrying about significance tests of confidence intervals: the model is wrong.

Andy Field

Econometrics fails miserably over and over again — and not only because of the additivity and linearity assumption. Read more…

Jürgen Habermas and Hans Albert on the weaknesses of mainstream economics

August 17, 2022 Leave a comment

from Lars Syll

On the Logic of the Social Sciences | Jurgen Habermas, Shierry Weber Nicholsen, Jerry A. Stark | Paperback OctavoThe weaknesses of social-scientific normativism are obvious. The basic assumptions refer to idealized action under pure maxims; no empirically substantive lawlike hypotheses can be derived from them. Either it is a question of analytic statements recast in deductive form or the conditions under which the hypotheses derived could be definitively falsified are excluded under ceteris paribus stipulations. Despite their reference to reality, the laws stated by pure economics have little, if any, information content. To the extent that theories of rational choice lay claim to empirical-analytic knowledge, they are open to the charge of Platonism (Modellplatonismus). Hans Albert has summarized these arguments: The central point is the confusion of logical presuppositions with empirical conditions. The maxims of action introduced are treated not as verifiable hypotheses but as assumptions about actions by economic subjects that are in principle possible. The theorist limits himself to formal deductions of implications in the unfounded expectation that he will nevertheless arrive at propositions with empirical content. Albert’s critique is directed primarily against tautological procedures and the immunizing role of qualifying or “alibi” formulas.

This critique of normative-analytic methods argues that general theories of rational action are achieved at too great a cost when they sacrifice empirically verifiable and descriptively meaningful information … Against the recent normativism of pure economics, Albert adduces the old viewpoint that an economic theory must make assumptions about the actions of subjects in their social roles … The system of exchange relationships is so little isolated from society as a whole that the social behavior of economic subjects cannot be comprehended independently of the institutional context, that is, the extra-economic motivational patterns: “Immunization against· the influence of so-called extra-economic factors leads to immunization against experience as such.”

Read more…

Dumb and Dumber — the Chicago economics version

August 11, 2022 1 comment

from Lars Syll

dumb_aSome years ago, in a lecture on the US recession, Robert Lucas gave an outline of what the New Classical school of macroeconomics today thinks on the latest downturns in the US economy and its future prospects.

Lucas shows that real US GDP has grown at an average yearly rate of 3 per cent since 1870, with one big dip during the Depression of the 1930s and a big — but more minor — dip in the recent recession.

After stating his view that the US recession that started in 2008 was basically caused by a run for liquidity, Lucas then goes on to discuss the prospect of recovery from where the US economy is today, maintaining that past experience would suggest an “automatic” recovery if the free market system is left to repair itself to equilibrium unimpeded by social welfare activities of the government.

As could be expected there is no room for any Keynesian-type considerations on eventual shortages of aggregate demand discouraging the recovery of the economy. As usual in the New Classical macroeconomic school’s explanations and prescriptions, the blame game points to the government and its lack of supply-side policies.

Lucas is convinced that what might arrest the recovery are higher taxes on the rich, greater government involvement in the medical sector and tougher regulations of the financial sector. But — if left to run its course unimpeded by European-type welfare state activities — the free market will fix it all. Read more…

Yanis Varoufakis on the irrelevance of mainstream economics

August 8, 2022 8 comments

from Lars Syll

Varoufakis is undoubtedly right — there is indeed something about the way mainstream economists construct their models that obviously doesn’t sit right.

One might have hoped that humbled by the manifest failure of its theoretical pretences during the latest economic-financial crises, the one-sided, almost religious, insistence on axiomatic-deductivist modelling as the only scientific activity worthy of pursuing in economics would give way to methodological pluralism based on ontological considerations rather than formalistic tractability. But Read more…

Frank Ramsey — a portrait and a critique

August 5, 2022 2 comments

from Lars Syll

Mainstream economics nowadays usually assumes that agents that have to make choices under conditions of uncertainty behave according to Bayesian rules, axiomatized by Ramsey (1931) and Savage (1954) — that is, they maximize expected utility with respect to some subjective probability measure that is continually updated according to Bayes theorem. If not, they are supposed to be irrational, and ultimately — via some “Dutch book” or “money pump” argument — susceptible to being ruined by some clever “bookie”.

Bayesian Stats Joke | Data science, Mathematik meme, Mathe witzeBayesianism reduces questions of rationality to questions of internal consistency (coherence) of beliefs, but – even granted this questionable reductionism – do rational agents really have to be Bayesian? As I have been arguing elsewhere (e. g. herehere and here) there is no strong warrant for believing so.

In many of the situations that are relevant to economics, one could argue that there is simply not enough adequate and relevant information to ground beliefs of a probabilistic kind and that in those situations it is not really possible, in any relevant way, to represent an individual’s beliefs in a single probability measure.

Say you have come to learn (based on your own experience and tons of data) that the probability of you becoming unemployed in Sweden is 10 %. Having moved to another country (where you have no own experience and no data) you have no information on unemployment and a fortiori nothing to help you construct any probability estimate. A Bayesian would, however, argue that you would have to assign probabilities to the mutually exclusive alternative outcomes and that these have to add up to 1 if you are rational. That is, in this case – and based on symmetry – a rational individual would have to assign a probability of 10% of becoming unemployed and 90% of becoming employed.

That feels intuitively wrong though, and I guess most people would agree. Bayesianism cannot distinguish between symmetry-based probabilities from information and symmetry-based probabilities from an absence of information. In these kinds of situations, most of us would rather say that it is simply irrational to be a Bayesian and better instead to admit that we “simply do not know” or that we feel ambiguous and undecided. Arbitrary and ungrounded probability claims are more irrational than being undecided in face of genuine uncertainty, so if there is not sufficient information to ground a probability distribution it is better to acknowledge that simpliciter, rather than pretending to possess a certitude that we simply do not possess.  Read more…

Economics and the law of the hammer

August 2, 2022 3 comments

from Lars Syll

As yours truly has reported repeatedly during the last couple of years, university students all over the world are increasingly beginning to question if the kind of economics they are taught — mainstream economics — really is of any value. Some have even started to question if economics is a science.

My own take on the issue is that economics Read more…

On statistics and causality

July 28, 2022 3 comments

from Lars Syll

Ironically, the need for a theory of causation began to surface at the same time that statistics came into being … 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 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’s crow is highly correlated with the sunrise; yet it does not cause the sunrise.

Unfortunately, statistics has fetishized this commonsense observation. 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 not allowed to say that X is the cause of Y — only that X and Y are “related” or “associated.”

Statistical reasoning certainly seems paradoxical to most people.

Take for example the well-known Simpson’s paradox. Read more…

Heckman on where causality resides

July 23, 2022 17 comments

from Lars Syll

James HeckmanI make two main points that are firmly anchored in the econometric tradition. The first is that causality is a property of a model of hypotheticals. A fully articulated model of the phenomena being studied precisely defines hypothetical or counterfactual states. A definition of causality drops out of a fully articulated model as an automatic by-product. A model is a set of possible counterfactual worlds constructed under some rules. The rules may be the laws of physics, the consequences of utility maximization, or the rules governing social interactions, to take only three of many possible examples. A model is in the mind. As a consequence, causality is in the mind.

James Heckman

So, according to this ‘Nobel prize’ winning econometrician, “causality is in the mind.” But is that a tenable view? Yours truly thinks not. If one as an economist or social scientist would subscribe to that view there would be pretty little reason to be interested in questions of causality at all.  And it sure doesn’t suffice just to say that all science is predicated on assumptions. To most of us, models are seen as ‘vehicles’ or ‘instruments’ by which we represent causal processes and structures that exist and operate in the real world. As we all know, models often do not succeed in representing or explaining these processes and structures, but if we didn’t consider them as anything but figments of our minds, well then maybe we ought to reconsider why we should be in the science business at all … Read more…

Mainstream economics — the triumph of ideology over science

July 17, 2022 11 comments

from Lars Syll

Research shows not only that individuals sometimes act differently than standard economic theories predict, but that they do so regularly, systematically, and in ways that can be understood and interpreted through alternative hypotheses, competing with those utilised by orthodox economists.

Senate Banking Subcommittee On Financial Institutions Hearing With StiglitzTo most market participants — and, indeed, ordinary observers — this does not seem like big news … In fact, this irrationality is no news to the economics profession either. John Maynard Keynes long ago described the stock market as based not on rational individuals struggling to uncover market fundamentals, but as a beauty contest in which the winner is the one who guesses best what the judges will say …

Adam Smith’s invisible hand — the idea that free markets lead to efficiency as if guided by unseen forces — is invisible, at least in part, because it is not there …

For more than 20 years, economists were enthralled by so-called “rational expectations” models which assumed that all participants have the same (if not perfect) information and act perfectly rationally, that markets are perfectly efficient, that unemployment never exists (except when caused by greedy unions or government minimum wages), and where there is never any credit rationing.

That such models prevailed, especially in America’s graduate schools, despite evidence to the contrary, bears testimony to a triumph of ideology over science. Unfortunately, students of these graduate programmes now act as policymakers in many countries, and are trying to implement programmes based on the ideas that have come to be called market fundamentalism … Good science recognises its limitations, but the prophets of rational expectations have usually shown no such modesty.

Joseph Stiglitz

The rational expectations hypothesis — one of the cornerstones of mainstream economics — presupposes, basically for reasons of consistency, that agents have complete knowledge of all relevant probability distribution functions. And Read more…

The ’empirical revolution’ in economics — some critical perspectives

July 12, 2022 3 comments

from Lars Syll

GDP - Business Review at BerkeleyMost research in economics nowadays involves empirical work … It is therefore odd to find a great deal of economic reasoning still starting from “standard theory”. Whilst it does generate predictions that can be tested empirically, it does not have an empirical foundation, but rather is based on a story about universal human nature … It remains true that the traditional models retain a central place, and accumulating evidence does not tend to lead to the abandonment of a conventional starting point, even when the two are in conflict …

The link from evidence into theory is similarly not always pursued in behavioural and experimental economics. One approach is to study human behaviour as a departure from homo economicus, explicitly to retain traditional theory as the starting point, and then to modify the analysis by incorporating important biases that deviate from this ideal … This involves two stages: the traditional assumptions of rationality, perfect information, etc., and then a correction. In terms of causal mechanism, neither of these represents an actually occurring process: the first stage is derived from axioms not observed behaviour and the second is a correction of the resulting error.

Michael Joffe

Although discounting empirical evidence cannot be the right way to solve economic issues, there are still, in my opinion, a couple of weighty reasons why we perhaps shouldn’t be too excited about the so-called ’empirical revolution’ in economics. Read more…

Threats to substantive relevance of natural experiments

July 8, 2022 Leave a comment

from Lars Syll

External validity poses a challenge for most kinds of research designs, of course. In true experiments in the social sciences, the study group is not usually a random sample from some underlying population. Often, the study group consists instead of a convenience sample, that is, a group of units that have been “drawn” through some nonrandom process from an underlying population. In other studies, one cannot even readily claim that the study group has been drawn from any well-defined population. In either case, one cannot confidently project estimated causal effects to a broader population, or attach estimates of sampling error to those projections. In most true experiments, in other words, causal inferences are drawn conditional on the study group—the particular set of units assigned to treatment and control groups. While randomization to treatment and control groups generally ensures that estimators of effects for the study group are unbiased (barring differential attrition or other threats to internal validity), whether these effects generalize to other populations is often an open question.

Thad Dunning

Yours truly’s view is that nowadays many social scientists maintain that ‘imaginative empirical methods’ — such as natural experiments, field experiments, lab experiments, RCTs — can help us to answer questions concerning the external validity of models used in social sciences. In their view, they are more or less tests of ‘an underlying model’ that enable them to make the right selection from the ever-expanding ‘collection of potentially applicable models.’ When looked at carefully, however, there are in fact not that many convincing reasons to share this optimism. Read more…

Economics as ideology

July 2, 2022 15 comments

from Lars Syll

capitalism-works-bestAlthough I never believed it when I was young and held scholars in great respect, it does seem to be the case that ideology plays a large role in economics. How else to explain Chicago’s acceptance of not only general equilibrium but a particularly simplified version of it as ‘true’ or as a good enough approximation to the truth? Or how to explain the belief that the only correct models are linear and that the von Neuman prices are those to which actual prices converge pretty smartly? This belief unites Chicago and the Classicals; both think that the ‘long-run’ is the appropriate period in which to carry out analysis. There is no empirical or theoretical proof of the correctness of this. But both camps want to make an ideological point. To my mind that is a pity since clearly it reduces the credibility of the subject and its practitioners.                   Frank Hahn

The Law of Demand

June 28, 2022 2 comments

from Lars Syll

Mainstream economics is usually considered to be very ‘rigorous’ and ‘precise.’ And yes, indeed, it’s certainly full of ‘rigorous’ and ‘precise’ statements like “the state of the economy will remain the same as long as it doesn’t change.” Although ‘true,’ this is, however — like most other analytical statements — neither particularly interesting nor informative.

As is well known, the law of demand is usually tagged with a clause that entails numerous interpretation problems: the ceteris paribus clause. In the strict sense this must thus at least be formulated as follows to be acceptable to the majority of theoreticians: ceteris paribus – that is, all things being equal – the demanded quantity of a consumer good is a monotone-decreasing function of its price …

Wissenschaftstheorie: Hans Albert feiert 100. Geburtstag - Forschung & LehreIf the factors that are to be left constant remain undetermined, as not so rarely happens, then the law of demand under question is fully immunized to facts, because every case which initially appears contrary must, in the final analysis, be shown to be compatible with this law. The clause here produces something of an absolute alibi, since, for every apparently deviating behavior, some altered factors can be made responsible. This makes the statement untestable, and its informational content decreases to zero.

One might think that it is in any case possible to avert this situation by specifying the factors that are relevant for the clause. However, this is not the case. In an appropriate interpretation of the clause, the law of demand that comes about will become, for example, an analytic proposition, which is, in fact, ​true for logical reasons, but which is thus precisely for this reason not informative …

Various widespread formulations of the law of demand contain an interpretation of the clause that does not result in a tautology, but that has another weakness. The list of the factors to be held constant includes, among other things, the structure of the needs of the purchasing group in question. This leads to a difficulty connected with the identification of needs. As long as there is no independent test for the constancy of the structures of needs, any law that is formulated in this way has an absolute ‘alibi’. Any apparent counter case can be traced back to a change in the needs, and thus be discounted. Thus, in this form, the law is also immunized against empirical facts. To counter this situation, it is in fact necessary to dig deeper into the problem of needs and preferences; in many cases, however, this is held to be unacceptable, because it would entail crossing the boundaries into social psychology.

Hans Albert

In mainstream economics there’s — still — a lot of talk about ‘economic laws.’ Read more…

Mainstream economics — the art of building fantasy worlds

June 25, 2022 2 comments

from Lars Syll

Mainstream macroeconomic models standardly assume things like rational expectations, Walrasian market clearing, unique equilibria, time invariance, linear separability and homogeneity of both inputs/outputs and technology, infinitely lived intertemporally optimizing representative household/ consumer/producer agents with homothetic and identical preferences, etc., etc. At the same time, the models standardly ignore complexity, diversity, uncertainty, coordination problems, non-market clearing prices, real aggregation problems, emergence, expectations formation, etc., etc.

How to Build a Fantasy Economy - YouTubeBehavioural and experimental economics — not to speak of psychology — show beyond doubt that “deep parameters” — peoples’ preferences, choices and forecasts — are regularly influenced by those of other economic participants. And how about the homogeneity assumption? And if all actors are the same — why and with whom do they transact? And why does economics have to be exclusively teleological (concerned with intentional states of individuals)? Where are the arguments for that ontological reductionism? And what about collective intentionality and constitutive background rules? Read more…

Free trade

June 22, 2022 6 comments

from Lars Syll

In 1817 David Ricardo presented — in Principles — a theory that was meant to explain why countries trade and, based on the concept of opportunity cost, how the pattern of export and import is ruled by countries exporting goods in which they have a comparative advantage and importing goods in which they have a comparative disadvantage.

Heckscher-Ohlin-HO-Modern-Theory-of-International-TradeRicardo’s theory of comparative advantage, however, didn’t explain why the comparative advantage was the way it was. At the beginning of the 20th century, two Swedish economists — Eli Heckscher and Bertil Ohlin — presented a theory/model/theorem according to which the comparative advantages arose from differences in factor endowments between countries. Countries have comparative advantages in producing goods that use up production factors that are most abundant in the different countries. Countries would mostly export goods that used the abundant factors of production and import goods that mostly used factors of production that were scarce.

The Heckscher-Ohlin theorem — as do the elaborations on in it by e.g. Vanek, Stolper and Samuelson — builds on a series of restrictive and unrealistic assumptions. The most critically important — besides the standard market-clearing equilibrium assumptions — are

— Countries use identical production technologies.

— Production takes place with constant returns to scale technology.

— Within countries, the factor substitutability is more or less infinite.

— Factor prices are equalised (the Stolper-Samuelson extension of the theorem).

These assumptions are, as almost all empirical testing of the theorem has shown, totally unrealistic. That is, they are empirically false. Read more…

Abduction — beyond deduction and induction

June 9, 2022 5 comments

from Lars Syll

Science is made possible by the fact that there are structures that are durable and independent of our knowledge or beliefs about them. There exists a reality beyond our theories and concepts of it. Contrary to positivism, yours truly would as a critical realist argue that the main task of science is not to detect event-regularities between observed facts, but rather to identify and explain the underlying structures/forces/powers/ mechanisms that produce the observed events.

Given that what we are looking for is to be able to explain what is going on in the world we live in, it would — instead of building models based on logic-axiomatic, topic-neutral, context-insensitive, and non-ampliative deductive reasoning, as in mainstream economic theory — be so much more fruitful and relevant to apply inference to the best explanation. Read more…

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