Jump to content

Talk:Rational expectations

Page contents not supported in other languages.
From Wikipedia, the free encyclopedia

Is it plagiarism?

[edit]

This page was basically copied and pasted from its external link.

http://www.colombialink.com/01_INDEX/index_finanzas_eng/rational_expectations.html

Foraday 16:52, 26 March 2007 (UTC)[reply]

rational expectations is a hypothesis or modeling technique, not a theory

[edit]

It is not even a model, it is an assumption used to derive the expectations term of a model, and so can be (and has been) applied to many different models. The intuition is, if the error term was not symmetrically distributed with a mean of zero, systematic profit opportunities exist. If the opportunities are discoverable, they will be exploited, eliminating the systematic bias and revalidating the original assumption. — Preceding unsigned comment added by 66.8.211.54 (talk) 06:28, 5 December 2012 (UTC)[reply]

Yes, these are good points. As it stands now, some of the article reads like a defense of something, like the efficient market hypothesis, when these things are distinctly separate. I will see if I can do a few edits to clean some of this up. Nwlaw63 (talk) 15:14, 16 January 2015 (UTC)[reply]

'Equilibrium' can mean steady state, or can mean mutual consistency of decisions

[edit]

No equilibrium means that nothing changes with time in a deterministic system. This is simply time translational invariance. In stochastic dynamics equilibrium, time translational invariance, means that the 1-point density, hence all 1-point averages (the mean, variance, any moment) are constants independent of time t. For higher order densities and correlations it means independence of the present time t, and dependence only on the lag time T. all other 'definitions' of equilibrium are wrong, are simply fudges invented to try to save the face of neo-classical econ and ratex. — Preceding unsigned comment added by 70.138.104.246 (talk) 17:59, 13 May 2012 (UTC)[reply]

I am removing (for the second time) a sequence of assertions by user jmccauley, who claims that rational expectations involves a misunderstanding of the concept of equilibrium. The text I removed is shown below:

The basis for the rational expectations model is based on a mathematical inconsistency (in Muth, 1961): a time varying price is derived from the assumption of market equilibrium. Equilibrium means time translationalinvariance, simple averages cannot change with time. Muth's (and Lucas's and Sargent's) violation of the definition of equilibrium is common in the economics and finance literature. For the correct definition of equilibrium (dynamic or statistical) see texts on ordinary diffeential equations, dynamical systems, statistical physics, or stochastic processes. Lucas tried to maintain the essence of neo-classical ideology by attempting to define away nonstationary processes, but this resulted only in self-organized confusion, not understanding of markets. Finance markets (and presumably all other markets) are nonstationary, are far from equilibrium, and all attempts by economists to understand and explain markets have failed.
References:
1. J.L. McCauley, K.E. Bassler, and G.H. Gunaratne, Martingales, Detranding Data, and the Efficient Market Hypothesis, Physica A37, 202, 2008.
2. K.E. Bassler, J. L. McCauley, & G.H. Gunaratne, Nonstationary Increments, Scaling Distributions, and Variable Diffusion Processes in Financial Markets, PNAS 104, 17297, 23 Oct. 2007.

This text asserts that 'equilibrium' refers to a system which is not changing over time. Many years ago, this was indeed the usual meaning of equilibrium in economics. But today, most economists use the word 'equilibrium' in a different sense, essentially the same way it is used in game theory: mutual consistency between agents' decisions. Economists do not claim to use the word in the same way statistical physicists use it.

The whole point of the rational expectations revolution was that some earlier adaptive expectations models implied behavior that was far from optimal. Imposing rational expectations means that agents know how the economy behaves, and make their decisions optimally taking this knowledge into account. In other words, the expectations on which agents base their decisions are consistent with the actual behavior of the economy. That is equilibrium in (roughly speaking) the sense of Nash. It is NOT equilibrium in the sense of statistical physics: there is no assumption that the economy is behaving in a constant way over time. An economic situation that is unchanging over time is nowadays usually called a 'steady state', which is NOT a synonym for 'equilibrium' in the Nash sense of the word. --Rinconsoleao (talk) 14:42, 26 December 2007 (UTC)[reply]

The basis for the rational expectations model is based on a mathematical inconsistency (in Muth, 1961): a time varying price is derived from the assumption of market equilibrium. Equilibrium means time translationalinvariance, simple averages cannot change with time. Muth's (and Lucas's and Sargent's) violation of the definition of equilibrium is common in the economics and finance literature. For the correct definition of equilibrium (dynamic or statistical) see texts on ordinary diffeential equations, dynamical systems, statistical physics, or stochastic processes. Lucas tried to maintain the essence of neo-classical ideology by attempting to define away nonstationary processes, but this resulted only in self-organized confusion, not understanding of markets. Finance markets (and presumably all other markets) are nonstationary, are far from equilibrium, and all attempts by economists to understand and explain markets have failed.

References: 1. J.L. McCauley, K.E. Bassler, and G.H. Gunaratne, Martingales, Detranding Data, and the Efficient Market Hypothesis, Physica A37, 202, 2008.

2. K.E. Bassler, J. L. McCauley, & G.H. Gunaratne, Nonstationary Increments, Scaling Distributions, and Variable Diffusion Processes in Financial Markets, PNAS 104, 17297, 23 Oct. 2007.

First sentence

[edit]

This article is suffering from excessive disclaimerism: its writing is so concerned with avoid misinterpretation that it's not being direct, succinct, and readable. I recommend that the first sentence in particular make some stab at a definition of rational expectations, rather than giving a detailed contextualization without even mentioning what the term means. The article is showing the effects of a contentious editing process, but that process should end with a nuanced and appropriate re-writing. And, I would do it myself, if I didn't have the apparently, woefully incorrect assumption that rational expectations meant that people were perfectly rational/utility optimizers in their decision making.71.224.206.164 (talk) 10:52, 17 January 2010 (UTC)[reply]

Definition now in first sentence. Nurg (talk) 04:24, 30 January 2010 (UTC)[reply]
That's Wikipedia's mode of operating. A bunch of useless editing and petty fights between pseudo-intellectuals who finally culminates into a bunch of sentences that are so crappy it's embarrassing. —Preceding unsigned comment added by 70.41.205.20 (talk) 05:34, 5 February 2010 (UTC)[reply]

Look out for possible copyright violations in this article

[edit]

This article has been found to be edited by students of the Wikipedia:India Education Program project as part of their (still ongoing) course-work. Unfortunately, many of the edits in this program so far have been identified as plain copy-jobs from books and online resources and therefore had to be reverted. See the India Education Program talk page for details. In order to maintain the WP standards and policies, let's all have a careful eye on this and other related articles to ensure that no material violating copyrights remains in here. --Matthiaspaul (talk) 12:34, 1 November 2011 (UTC)[reply]

Definition not encyclopedic style

[edit]

A term should be defined by indicating what it means, not what it implies. No one would define a first derivative as something that must vanish in an optimum. I change the definition accordingly.--Herbert81 (talk) 17:42, 14 October 2015 (UTC)[reply]

@Buldri: Are you serious with your second revert? It is encyclopedic style to define something by stating what it is rather than by an indication of its usefulness or by arguable characteristics. A rational expectation is an expected value in the mathematical sense. Fullstop. I wouldn't bother if you put it in the plural but the indirect characterization you offer is unacceptable. --Herbert81 (talk) 17:39, 18 October 2015 (UTC)[reply]

@Herbert81: Please take a more serious tone. First, if you had bothered reading what you just removed you would have seen that it defined "rational expectations" by what the terms means. Second, if you had any insight into the topic of this article you would maybe have realized that it is not about the mathematical definition of "a rational expectation", but about the economic concept "rational expectations". Buldri (talk) 21:50, 18 October 2015 (UTC)[reply]

@Buldri: "Defining" rational expectations as model consistent expectations is circular. To define rational expectations as mathematical expected values is preferable because an expected value is precisely defined in mathematics. I do not understand what you mean by "economic concept" as opposed to a mathematical definition. Perhaps someone else should consider this exchange.--Herbert81 (talk) 09:53, 19 October 2015 (UTC)[reply]

Dr. Davila's comment on this article

[edit]

Dr. Davila has reviewed this Wikipedia page, and provided us with the following comments to improve its quality:


too vague/imprecise/lacking focus

one could think that this reflects the very historical development of the concept, which was plagued with misconceptions and corrections, back and forth, but it is wrong to present it nowadays with all that noise. it makes a disservice to students.

the RE assumption is a just consistency requirement between the expectations held by optimisers about some value(s) influenced by their choices (based on those expectations) and the values actually implied by their choices. Should the two things not be the same, the agents would exhibit some kind of irrationality/arbitrariness in holding those expectations, or they don't understand the consequences of their choices. Be as it may, if expectations are nor "rational" (in the sense of the RE assumption), agents are not rational, and that just leads to another paradigm which is not that of 99% of economics, for many good reasons (and some bad ones).


We hope Wikipedians on this talk page can take advantage of these comments and improve the quality of the article accordingly.

We believe Dr. Davila has expertise on the topic of this article, since he has published relevant scholarly research:


  • Reference : The Rationality of Expectations Formation, The B.E. Journal of Theoretical Economics 16(2), 515-543 (2016)

ExpertIdeasBot (talk) 14:53, 8 August 2016 (UTC)[reply]

Possible extension to this article

[edit]

This article should have a more wider perspective than it currently has. This is the question of framing the Rational Expectations in a larger phenomenon called biopolitics. The core of biopolitics is a claim that governance can be done using more hidden tools than the tools of modern democracy. This is actually the claim known as 'Hayek's crystal'. Hayek uses the word 'law' to refer both legislation and a law of nature. David Hume has explained this with the claim that a human being can not be without expecting. Hume has also pointed out that this is a question of 'human nature'. Human nature is not limited to expectation.

Rational Expectations does not empty the concept of biopolitics in economics or Hume's notion about human nature. It leaves outside a vast domain that is both known and unknown at the same time. The environment we live today includes the synthetic environment of electrical devices. These tools have been a remarkable part of the modern era. The difference is that the current low voltage systems are the product of the postmodern era. This difference should be highlighted. The devices that measure our heartbeat etc. have been in the market for a long time and the technology has been advancing fast. There are now devices that are more or less implants to human bodies and connected to the nervous system. But still electricity is understood as separate from a human body and we are living at the same time in the middle of the wireless communications systems' signals.

Rational Expectations is not only a feature in economics. It is a model of governance. This article about Rational Expectations has been updated with minor constraints. This implies that Rational Expectations is no more the focus of economics but on the contrary. The expectations are currently so crudely utilized in the political discourse focused on so-called sound economic policies, that it seems to be the very intention to blow the expectations out of the toolbox of economics. This would lead more or less to the state of what is called Pyrrhomism that Hume saw as to be prohibited. How can the powerholders allow this to happen? The explanation is that there is an alternative paradigm of governance. The weakness of Rational Expectations is that metacognition can be a major obstacle for it. Therefore the focus of the investigation should be in unconscious processes.

There is the major problem that the focus on expectations leads to skepticism to expectations in general. This can damage the modern institutions that are operating on discourses, such as the parliamentary system. Focusing on expectations can in fact damage the democracy at the same time economics has established a beeper biological base.Dancing Mickey Mouse (talk) 22:50, 21 September 2016 (UTC)[reply]

Reflexive events and full blown rational expectations

[edit]

These details describing reflexive events using full-blown rational expectations are alarming. Soros states that the hypothesis is not valid for these events all the time. This is actually a repeat of the famous claim that "You can fool all the people some of the time and some of the people all the time, but you cannot fool all the people all the time".

I interpret Soros' claim that using full-blown rational expectations of this kind all the time is not possible, but it is possible to use these now and then. In addition to this there is the possibility to use these in different geographical locations. What is needed is that people have trust on the people using them. Burdekin and Langdana claim that one of the key components in RE is trust. This should be absent in the world of game theory but most of the people are not aware of it.

The RE does not require that all people buy the predictions (induced expectations) and RE does not require it. The operators themselves do not buy them. There has been in the literature the concept "emotional attack". This describes well what happened in in 2001. What happened was also a prime example of Milton and Rose Friedman's Free to Choose claim about the usefulness of television regarding the emotions.

The Soros 1998 book includes a claim that the political stage of the United States has to be rearranged. He also referred to the reflexivity of Greek drama in it. In addition to that he demanded there the usage of full-blown rational expectations. Soros' Open Society organizations work still around the world and these organizations did not cease to exist after the coups in the socialist countries.

An interesting detail is that this 1998 book cover does not simply read "The Crisis of Global Capitalism". Little, Brown and Company 1998 print reads "The Crisis George of Global Soros Capitalism": http://www.alibris.co.uk/The-Crisis-of-Global-Capitalism-Open-Society-Endangered-George-Soros/book/1398212? Who is Crisis George?Dancing Mickey Mouse (talk) 21:27, 23 September 2016 (UTC)[reply]

Unsourced and off-topic OR deleted from the article

[edit]

SPECIFICO talk 22:03, 25 September 2016 (UTC)[reply]

References

  1. ^ Evans, G. W. and G. Ramey (2006) Adaptive Expectations, Underparameterization and the Lucas Critique. Journal of Monetary Economics, vol. 53, pp. 249-264.
  2. ^ Allais, M. (1965), Reformulation de la théorie quantitative de la monnaie, Société d’études et de documentation économiques, industrielles et sociales (SEDEIS), Paris.
  3. ^ Friedman, M. (1968), Factors affecting the level of interest rates, in Savings and residential financing: 1968 Conference Proceedings, Jacobs, D. P., and Pratt, R. T., (eds.), The United States Saving and Loan League, Chicago, IL, p. 375.
  4. ^ Barthalon, E. (2014), Uncertainty, Expectations and Financial Instability, Reviving Allais’s Lost Theory of Psychological Time, Columbia University Press, New York.
  5. ^ Soros, George (1998): The Crisis of Global Capitalism: Open Society endangered. Little, Brown and Company.
  6. ^ Veblen, Thorstein (1919): The Intellectual Pre-Eminence of Jews in Modern Europe. Political Science Quarterly. Vol.34, No.1 (March 1919) pp. 33-42
  7. ^ Soros, George (1998): The Crisis of Global Capitalism: Open Society endangered. Little, Brown and Company.
  8. ^ Rand, Ayn: Atlas Shrugged. Penguin Books. pp. 1167-1168
  9. ^ http://www.nobelprize.org/nobel_prizes/economic-sciences/laureates/1976/friedman-lecture.pdf

Vandalism in deleting material from the article

[edit]

The material deleted is now recovered. The deletion was vandalism. If the knowledge and references do not please you there should also be an argument that is valid. Is this again a trial to escape the possible rejection?

"When Milton received his Medal of Freedom in 1988, President George H. W. Bush said jokingly in his speech that Rose was known for being the only person to ever have won an argument against her husband." (Wikipedia EN Rose Friedman)Dancing Mickey Mouse (talk) 21:01, 5 October 2016 (UTC)[reply]

Rat Ex vs Rat Choice

[edit]

Re [1] and the sentence

"Hence, it is important to distinguish the rational-expectations assumption from assumptions of individual rationality and to note that the first does not imply the latter. Rational expectations is an assumption of aggregate consistency in dynamic models. In contrast, rational choice theory studies individual decision making and is used extensively in, among others, game theory and contract theory."

Personally, while I realize this is unsourced, I find this statement useful as a clarification. People DO in fact confuse Rational Expectations with Rational choice or Rationality as used in game theory (common knowledge of rationality etc.) or even the Independence Axiom in Expected Utility Theory. But there is indeed a couple problems with the wording.

First, rat ex isn't just about aggregate consistency though that is the most common setting. Muth's work was micro. Second, the phrase "in contrast" isn't quite appropriate as it suggests there's some kind of opposition here. But it's just different concepts and indeed they're often used together (the representative agent in most macro models has BOTH rational expectations AND satisfied the usual axioms of rationality from choice theory). Third, I'm not sure why only game theory and contract theory should be mentioned. I guess it's because those are two areas where the idea of Individual Rationality comes into play. But almost all of micro uses rational choice theory, so I don't know why these should be singled out.Volunteer Marek (talk) 00:13, 19 July 2017 (UTC)[reply]

I'd agree with 1, strongly agree with 2. However I feel that 3 is a complex issue and that the proposed text is at best misleading. Lucas' initial thrust in the 1970s was to reject models that had agents stupidly being fooled by false "expectations" that enabled the results of the recently discredited neo-Keynesian Philips Curve models. In the context of this article, my initial objection was that, with no RS cited, we have no touchstone to ensure that we get this right. It's the view of an active editor based on his personal understanding of the issue. My knowledge of the current literature is not good enough to suggest a proper source or to comment on all the ways RE ties to other fundamental concepts and processes casually cited in this text, but it's disturbing that the reference now offered does not seem to fully support the mooted text. SPECIFICO talk 00:57, 19 July 2017 (UTC)[reply]
Those neo-Keynesian Philips Curve models have rational expectations in them. Non-rational expectations was more like IS/LM or the Friedman-Phelps Philips Curve (which was pre Lucas). I'll see if I can find a source which explicitly addresses the distinction, though since RatEx have been so widely accepted nobody really writes about it anymore (aside from specialized literatures on learning dynamics and such).Volunteer Marek (talk) 03:20, 19 July 2017 (UTC)[reply]
That's right. I think I'm sooo old that what I call "neo-" Keynesian was actually the Samuelsonized/postwar IS/LM thing. The new neo's are much better stuff. SPECIFICO talk 12:01, 19 July 2017 (UTC)[reply]

India Education Program course assignment

[edit]

This article was the subject of an educational assignment at Symbiosis School of Economics supported by Wikipedia Ambassadors through the India Education Program during the 2011 Q3 term. Further details are available on the course page.

The above message was substituted from {{IEP assignment}} by PrimeBOT (talk) on 20:03, 1 February 2023 (UTC)[reply]

Issues with criticisms and implications

[edit]

Before introducing the policy‑ineffectiveness proposition, the most immediate implication of rational expectations is that—conditional on the information set available to the agents—forecast errors are unpredictable.

The first criticism is misleading on this basis. Imperfect information and rational expectations are not mutually exclusive; agents who appear “irrational” may actually be fully rational but constrained by a limited information set. A clearer formulation of this critique is that rational expectations require agents to process their information set in complete accordance with the underlying model and the expectations of all other agents. This imposes an unrealistically high computational burden on individuals, especially in environments with incomplete markets.

One final point to consider: rational expectations serve as the solution concept for dynamic models that incorporate uncertainty. When agents are not assumed to be rational, an alternative expectations‑formation mechanism must be introduced—and many of those alternatives involve assumptions that are at least as strong, if not stronger, than those underlying rational expectations. Quant-macro (talk) 03:38, 19 February 2026 (UTC)[reply]