The Spin Stops Here!
  Decision-Making Under Severe Uncertainty
Faqs | Help | @ | Contact | home  
voodoostan info-gap decision theory info-gap economics severe uncertainty mighty maximin robust decisions responsible decisions

Info-Gap Decision Theory Campaign

Last modified: Friday, 30-Jul-2010 23:25:29 MST

Info-Gap decision theory is a classic example of a voodoo decision theory. The main goal of this campaign is to contain its spread in Australia. I embarked on this mission at the end of 2006 in response to the growing number of senior scholars/analysts around me who became involved in the promotion of this theory in Australia, and elsewhere. The intended completion date of the project is January 1, 2012.

Introduction

The principal objectives of the campaign are to:

  1. Convince senior info-gap scholars/analysts that -- contrary to the claims made in the primary info-gap texts -- Info-gap decision theory is not a distinct, new theory, let alone is it revolutionary, and radically different from all current theories for decision under uncertainty.

  2. Convince senior info-gap scholars/analysts that --- contrary to the claims in the info-gap literature -- info-gap decision theory does not, indeed is unable to, seek decisions that are robust against severe uncertainty.

  3. Explain in detail Info-gap decision theory's relation to classical decision theory and control theory.

  4. Explain in detail the fundamental flaws in info-gap decision theory.

  5. Clarify to info-gap scholars/analysts the basic issues that are encountered in decision-making under severe uncertainty and convince them that info-gap decision theory does not address these issues.

  6. Document the lessons learnt from this project in two easily accessible books:

    • One that seeks to give a comprehensive, formal critique of info-gap decision theory.

    • The other designed to answer the question:
      How is it possible that obviously flawed theories, such as info-gap decision theory, gain a footing in the academic world?

To date, I have accomplished the first five objectives.

Work on the two books is well underway. My plan is to complete the first in the middle of 2011 and the second sometime in 2012. Sample chapters of the first book will be posted on this website soon.

So, stay tuned!

How to read my blogs, essays, articles, books, etc. on Info-Gap decision theory

My criticism of info-gap decision theory is unrelenting and very harsh. This is a consequence of the following facts:

I submit that it is the duty of academics, indeed of any senior scholar/analyst, to bring these facts into full view not only because it is important to set the record straight, but also for the benefit of PhD students, and early career researchers, as well as analysts and researches who -- as my experience has shown -- tend to fall for the Info-Gap rhetoric due to a lack of familiarity with decision theory, optimization theory, control theory, etc.

Apart from my harsh criticism of the spin and empty rhetoric that have become the trademarks of the Info-Gap literature, I have also been unrelenting in my critique of the inexcusable disrespect shown in the Info-Gap literature for the state-of-the-art. I have shown that Info-Gap publications persistently take no account whatsoever of topics, results, issues, etc., that bear directly on Info-Gap decision theory. To make the point, I have adopted an informal "SNHNSNDN" (see nothing, hear nothing, say nothing, do nothing) index to rank Info-Gap publications accordingly.

The best example of a publication that ranks extremely high on this index is Ben-Haim's (2010) new book on Info-Gap decision theory, namely Info-Gap Economics: An Operational Introduction. Instead of addressing the criticism directed at Info-Gap decision theory, this book remains completely oblivious to it, and this despite the serious nature of this criticism and the author being fully aware of it. Also, the book deals with robust decision-making in economics, yet it is completely oblivious to the extensive literature on this topic.

Of course, some info-gap scholars are not particularly thrilled with my criticism, especially my "style". So let me emphasize that in all my writing on this topic, namely in my blogs, essays, and articles, I am scrupulously fair:

I might add that my extensive use of quotes from Info-Gap publications has proved extremely important and effective in my campaign, as it enabled me to demonstrate the extent to which spin and empty rhetoric are used in this literature.

Still, if you find certain statements too harsh, do not hesitate to point them out to me and I shall re-examined them carefully.

Regarding the use of the word Voodoo in such phrases as "info-gap decision theory is a voodoo decision theory par excellence".

Apparently, some Info-Gap scholars believe that terms such as "Voodoo economics", "Voodoo Science", "Voodoo mathematics", "Voodoo statistics, etc. should not be used in academic discussions.

So click here for the meaning of "Voodoo" in this discussion ...

Let me explain what I mean by the term "voodoo decision theory" in this discussion. This is important because some of my colleagues take great umbrage at my labeling Info-gap decision theory a "voodoo decision theory".

According to the Encarta online Encyclopedia,

Voodoo n

  1. A religion practiced throughout Caribbean countries, especially Haiti, that is a combination of Roman Catholic rituals and animistic beliefs of Dahomean enslaved laborers, involving magic communication with ancestors.

  2. Somebody who practices voodoo.

  3. A charm, spell, or fetish regarded by those who practice voodoo as having magical powers.

  4. A belief, theory, or method that lacks sufficient evidence or proof.

My usage of the term "voodoo decision theory" is in line with the last meaning listed above. So roughly, in this discussion voodoo decision-making is a decision-making process that is guided and/or inspired by a voodoo decision theory, that is a theory that lacks sufficient evidence or proof and/or is based on utterly unrealistic and/or contradictory assumptions, spurious correlations, and so on.

This reading is also in line with the widely used terms Voodoo Economics, Voodoo Science and Voodoo Mathematics.

I should point out, though, that the term "Voodoo Decision Theory" is not my coinage (what a pity!):

The behavior of Kropotkin's cooperators is something like that of decision makers using the Jeffrey expected utility model in the Max and Moritz situation. Are ground squirrels and vampires using voodoo decision theory?
Brian Skyrms (1996, p. 51)
Evolution of the Social Contract
Cambridge University Press.

I have been told on numerous occasions that my lectures/seminars/tutorials on this campaign and related topics are

I greatly enjoy these activities, so do not hesitate to contact me if you are interested in organizing such a lecture/tutorial/workshop in your organization.

Preliminary reading

If you are not familiar with this campaign, you would do well to read the following recently published article, as it provides a comprehensive analysis explaining in detail why Info-Gap decision theory's fundamental flaws render it a voodoo decision theory par excellence.

Sniedovich, M.
A bird's view of info-gap decision theory
Journal of Risk Finance, 11(3), 268-283, 2010.

Click here for more/less information on this article ...

A short explanation of the article's title is in order.

The objective of this title is to point out that to be able to make clear how deeply flawed Info-Gap decision theory is, it is instructive to go beyond the technical details of the mathematical models deployed by this theory and to examine it as it were from above. That is, by taking a bird's view on this theory it is possible to bring out forcefully that Info-Gap decision theory's fundamental flaws are due to its violation of universally accepted norms that govern scientific reasoning.

For instance:

  • Garbage in -- Garbage Out.

  • Results can be only as good as the estimates on which they are based.

  • A theory must avoid self-contradiction.

I show that Info-Gap decision theory's violation of these basic norms of scientific reasoning earns it the title voodoo decision theory.

Also note that:

In this article I again set the record straight on the myth promulgated in the info-Gap literature that this theory is unique, distinct, novel, revolutionary and radically different from all current theories for decision under uncertainty. That is, I prove, yet again, that info-gap's robustness model is an instance of the most well-known robustness model: Wald's Maximin model (circa 1940).

I also show that Info-Gap's robustness model is not just an instance of Wald's Maximin model. I show that it is in fact that instance of Wald's Maximin model which is known universally as Radius of Stability Model. This model has been used in areas such as numerical analysis, applied mathematics, control theory and parametric programming at least since 1962 as a tool for analyzing local stability (robustness), that is robustness with respect to small perturbation in the nominal value of an object (parameter, matrix, function, model, etc).

The bird's view on Info-Gap decision theory thus enables to make vivid the absurd in Info-Gap's central proposition to employ this local model of robustness as a means for the modeling, analysis, and management of severe uncertainty. Namely, it demonstrates the absurd in Info-gap's proposition to apply this model to problems, systems, situations etc., where the estimate is poor and can be substantially wrong, and where the uncertainty space is vast (can even be unbounded), and where the uncertainty model is non-probabilistic and likelihood-free.

Remark:

As an illustration of how illuminating a bird's view on a "system" can be, take a look at what may well be the black Cockatoo's perspective on an interesting Australian project.

Click here to show/hide the bird's view of this project.


Click here to hide the picture

This is a January 2006 bird's eye view of the massive Super Pit, currently the largest open cut gold mine in Australia.

Some facts about this pit, taken from http://www.superpit.com.au/FAQ/tabid/72/Default.aspx



So, why the campaign?

This is an excellent question!

Given that the proofs demonstrating Info-Gap decision theory's fundamental flaws are well documented, indeed have been available to the public since the end of 2006; and given that senior Info-Gap scholars/analysts now concur with the basic points that I raise in my criticism, why the need for this campaign?

The answer obviously is that despite this fact, Info-Gap decision theory is continued to be used and promoted in Australia (and elsewhere) by senior academics and research centers.

For a glimpse of why this campaign is still active, have a look at the latest episode of the

Info-Gap Spin Goes Marching in !
Info-Gap Economics Workshop
Durham University, UK

It is most illuminating.

The good news

... is that, apparently for the first time, an official Government commissioned report has taken into account my criticism of Info-Gap decision theory.

This is long overdue!

Sadly, it is not an Aussie report!

As they say,

You cannot be a prophet
in your own land!
Progress Report
What's next?

What a pity!

What a waste!

I hope that AU government agencies that sponsor info-gap projects will soon follow suit and take a fresh look at this theory.

This is long overdue.

More importantly: I hope that senior academics promoting this theory in Australia and elsewhere will reconsider their position, especially insofar as supervising PhD students on this subject.

This is long overdue!

The report I am referring to is the 2009 Department for Environment Food and Rural Affairs (DEFRA) report. To be precise I am referring to the following paragraph on page 75 of the report:

More recently, Info-Gap approaches that purport to be non-probabilistic in nature developed by Ben-Haim (2006) have been applied to flood risk management by Hall and Harvey (2009). Sniedovich (2007) is critical of such approaches as they adopt a single description of the future and assume alternative futures become increasingly unlikely as they diverge from this initial description. The method therefore assumes that the most likely future system state is known a priori. Given that the system state is subject to severe uncertainty, an approach that relies on this assumption as its basis appears paradoxical, and this is strongly questioned by Sniedovich (2007).

Mervyn Bramley, Ben Gouldby, Anthony Hurford, Jaap-Jeroen Flikweert
Marta Roca Collell, Paul Sayers, Jonathan Simm, Michael Wallis
Delivering Benefits Through Evidence
PAMS (Performance-based Asset Management System)
Phase 2 Outcome Summary Report (PDF File)
Project: SC040018/R1
Environment Agency -- December 2009
Department for Environment Food and Rural Affairs
UK

Due to its "diplomatic language", the point made by this paragraph may not be entirely clear to all readers .

So, let me clarify it.

You don't have to be an expert in Decision Theory to figure this out.

But, .... if Info-gap's failings are so great, how is it that senior academics continue to promote such a fundamentally flawed theory?

Hence, ... my campaign continues ....

Its main thrust is to make it clear that:

I should make it clear that although my campaign focuses primarily on the situation in Australia, Info-gap has adherents in other countries as well:

  • Australia

  • Canada

  • Finland

  • France

  • Germany

  • Israel
  • Japan

  • Netherlands

  • Norway

  • Sweden

  • UK

  • USA
Official Completion Date of the Campaign

11:59PM, January 1, 2012

to go!
Melbourne time
  Latest News  
   
  Supplementary Material  

Table of contents

Overview

The fundamental flaws of Info-Gap decision theory are profoundly grave but at the same time, are easy to identify and describe ("prove") formally. This I have done at the end of 2006.

Hence, the objective of this campaign is not — as some would have it — to debunk Info-Gap decision theory. This relatively easy task has already been accomplished long ago.

Rather, the main objective of this campaign — and this has proved more difficult — is to dissuade adherents of Info-Gap from using what is an obviously profoundly flawed decision-making theory.

Since most users and promoters of Info-Gap decision theory in Australia (and elsewhere) are academics, this campaign is very much "academic" in nature. In other words, it concentrates on expounding why the use and promotion of Info-Gap decision theory is bad for science in general and for the science of decision-making in particular.

I encourage you to read the short

Call for the Reassessment of the Use and Promotion of Info-Gap Decision Theory in Australia
PDF version                   HTML version

My recent compilation of FAQs about Info-Gap decision theory should be of interest to Info-Gap users/promoters, as well as to persons who may want to learn what Voodoo Decision Theory is all about:

Frequently Asked Questions About Info-Gap Decision Theory
PDF version                  HTML version

In case you are unfamiliar with it, my criticism of Info-Gap Decision Theory is now well documented in many articles and presentations, including

WIKIPEDIA article on Info-Gap Decision Theory

Also, the criticism is very harsh.

The harshness is proportional to the severity of the flaws in Info-Gap Decision Theory and the level of promotion that it receives in Australia and elsewhere, for instance the AEDA 5-day workshop on Info-Gap Applications in Ecological Decision Making (University of Queensland, September 15-19, 2008).

The degree of harshness often increases in response to additional misguided arguments put forward by Info-Gap proponents in repeated futile attempts to explain the basic flaws. For instance the repeated misguided futile attempts to explain why Info-Gap's robustness model is not a Maximin model.

The October 2008 issue of Decision Point features an article by Mark Burgman in which he comments on some of the issues that I raised in the September issue regarding fundamental flaws in info-gap decision theory.

I address Burgman's comments in the following article:

Info-Gap decision theory and the small applied world of environmental decision-making
PDF version                   HTML version

If you have any questions about this project, please read:

Frequently Asked Questions About Info-Gap Decision Theory

A brief history:

The origins of this project go back to October 2003, when I was invited to a seminar on Info-Gap Decision Theory. Since then I was asked on several occasions to express my views on this theory. Until the end of 2006 I did this in informal discussions, usually over a cup of coffee.

But a number of reasons prompted me at the end of 2006 to make my criticism public and to launch this project. I shall be happy to discuss these reasons with interested persons over a cup of coffee (skinny latte, no sugar, please!).

The Flaws:

The short version of this story is as follows:

Info-Gap Decision Theory is afflicted with a number of flaws, some fundamental, some more serious than others. In this discussion I examine only two of these, which I take to be fundamental, namely:

The first flaw is mostly "academic" in nature in that it has to do primarily with scholarship. That is, whereas Info-Gap Decision Theory is presented as a distinctive, new, revolutionary theory that is radically different from all current theories for decisions under uncertainty, the truth of the matter is that its centerpiece, the jewel in its crown, namely its generic robustness model

is a simple instance of none other than the most famous model in classical decision theory and robust optimization, namely Wald's (1945, 1950) Maximin model. For the purposes of this discussion we consider the following classic format of the general Maximin model:

In other words, this flaw constitutes a classic case of a re-invention of a (square) wheel.

The second flaw is both "academic" and "methodological". The methodological aspect is of the utmost importance here: by definition Info-Gap's robustness model is inherently local, hence it is thoroughly unsuitable for decision in the face of severe uncertainty. In other words, under conditions of severe uncertainty Info-Gap knowingly restricts its robustness analysis to the immediate neighborhood of a wild guess, a poor indication of the true value of the parameter of interest, in short an estimate that is likely to be substantially wrong.

In the language of the Land of No Worries,

Decision-Making Under Severe Uncertainty a la Info-Gap Decision Theory
Fundamental Difficulty Robust Solution
The estimate we have is a wild guess, a poor indication of the true value of the parameter of interest, and is likely to be substantially wrong. No worries, mate!
Conduct the analysis in the immediate neighborhood of the estimate!

This of course means that Info-gap decision theory openly violates the Garbage In -- Garbage Out Axiom, a fact that renders it a voodoo decision theory par excellence.

But the trouble here is that this fact is camouflaged by a prolix rhetoric which conceals the huge incongruity between the verbiage describing the severe uncertainty, that presumably gave rise to Info-Gap decision theory, and the actual treatment that this theory prescribes for severe uncertainty.

The Info-Gap literature bursts with graphic descriptions of the (Knightian) uncertainty which is its concern. It dwells on the magnitude of this uncertainty, on the monumental challenges that it presents in decision making, and on the fact that "conventional" methods are unable to cope with these challenges.

Yet, for all this "sound and fury", all that Info-Gap has to offer to meet these daunting challenges is a run-of-the-mill Maximin robustness analysis in the immediate neighborhood of a wild guess.

So, what we have here, at best, is a classic case of "much ado about nothing".

The problem is, of course, that this rhetoric has the potential of leading the unwary reader astray. The following is a case in point:
The Info-Gap/Maximin Saga Continues ...

These two flaws are so obviously detrimental to this theory that people often ask me how is it that they were not taken up at the outset, in 2001, with the publication of the first book on Info-Gap decision theory (Ben-Haim 2001).

On this I can only speculate but I shall not do it here and now.

On the other hand, what I can say is this: in all likelihood my mission to convince the Father of Info-Gap and his followers that Info-Gap decision theory is fundamentally flawed, will take some time. This is so primarily because Info-Gap proponents again and again pull out the same tired arguments that fail to address my criticism. This seems to sustain naive Info-Gap users.

As an example, consider what seems to be a straightforward issue:

The Info-Gap/Maximin connection:

If you are at home with the mathematical modeling aspects of Maximin, you will note, by inspection, that

and that consequently Info-Gap's robustness model is a simple, typical Maximin model.

Alternatively, you may find the following Maximin representation of Info-Gap's robustness model more intuitive:

where the double lined R denotes the real line.

Yet, the following flawed, ill-conceived Info-Gap/Maximin disconnection

is used time and again by Info-Gap proponents as a "proof" that Info-Gap's robustness model is not a Maximin model.

The question then is this:

Why should Info-Gap proponents use a conceptually ill-considered, technically flawed model when simple, perfectly healthy, good looking, 100% correct Maximin models are readily available for the job?

I have no rational explanation for this phenomenon. What I can say is this:

Using the logic behind the formulation of the invalid model, it is easy to prove all sort of interesting things. For example, we can easily prove that Q(x):=x2+x -1 is not a polynomial. The proof is simple and it goes like this: clearly P(x):=x3 is a polynomial. Clearly Q(x) is not equivalent to P(x). Thus, clearly Q(x) cannot possibly be a polynomial.

Indeed, using this logic you would have no trouble at all to show that Jack, a three year old Australian kangaroo, is not a marsupial. The formal proof is as follows:

Proof:

QED.

The general Maximin model is extremely versatile so there are countless instances thereof in the literature. They come in a variety of forms thus offering the modeler a flexible and powerful modeling tool. In some cases the choice of a proper instance of this general model for a particular application is routine and straightforward, in others it can be difficult and may require a considerable mathematical modeling effort. So the fact that a particular instance of the general model is not suitable for a particular application does not imply that all other instances are also unsuitable for this application.

In short, Info-Gap proponents confuse two tasks related to the Info-Gap/Maximin connection:

The task on the agenda as far as the Info-Gap/Maximin connection is concerned is Task A. We want to find a user-friendly Maximin formulation for Info-Gap's generic robustness model. The point is that a number of such formulations are readily available and the question is which of these is the most suitable.

Unfortunately, Info-Gap proponents try to resolve the Info-Gap/Maximin connection issue through Task B. In other words, they labor hard to explain why Info-Gap's robustness model is not a Maximin model in an attempt to show that this is so.

But as I have indicated above, it is a simple exercise to construct Maximin formulations for Info-Gap's robustness model. Therefore, Task B is of no interest to us in the discussion on the Info-Gap/Maximin connection. For this reason it is difficult to fathom the logic behind this approach to the Info-Gap/Maximin connection.

What is to be gained from repeated analyses of the similarities and differences between Info-Gap's robustness model and an ill-conceived instance of the general Maximin model that is unsuitable for the job?

As an aside, it should be clear to anyone who is well-versed in decision theory and/or mathematical modeling that Task B is trivial. After all, all the instances of the general Maximin model that are used in classical decision theory, applied mathematics, and statistics are not equivalent to Info-Gap's robustness model. This means that all one needs to do to accomplish Task B is to open a relevant textbook and pick any one of the Maximin models that he/she may find there. For example, consider this classic model

This instance of the general Maximin model is definitely not equivalent to Info-Gap's generic robustness model. So what? There are myriads of other instances of the general Maximin model that are not equivalent to Info-Gap's robustness model either. So what?

To show that Info-Gap's robustness model is a Maximin model it is sufficient to show that at least one instance of the general Maximin model is equivalent to Info-Gap's generic robustness model. Note that we have already shown above that there are at least two such instances, hence we have accomplished Task A. For the record I should stress that there are other possible Maximin formulations of Info-Gap's robustness model.

To reiterate then, the flaw in Ben-Haim's approach to the Info-Gap/Maximin connection issue is that he tries to accomplish the wrong task, namely Task B, when perfectly valid solutions to the real task, namely Task A, are starring him in the face. The issue is about a connection, not a disconnection, and as it turns out, even this is a non-issue.

So why is the "Info-Gap/Maximin Connection" issue kept alive by Info-Gap proponents?

I have no answer to this valid question. Perhaps the reason is their inability to come to terms with the fact that -- contrary to the accepted wisdom in Info-Gap circles -- the Info-Gap robustness model is not "revolutionary" at all, but rather a simple instance of none other than the most famous robustness model in classical decision theory and robust optimization, the Mighty Maximin.

The inference is then this:

And to reiterate how straightforward the modeling issues on the agenda are, consider again the following snapshot of the situation:

Info-Gap proponents take themselves to show the following disconnection (Task B):

On the other hand, I formally prove the following connection (Task A):

Note that the repeated "demonstrations" that the specific (invalid) instance of the general Maximin model does not do the job here in no way contradicts the fact that the two valid instances shown above do an excellent job here.

For some strange reason Ben-Haim gives Info-Gap the authority to treat α as a decision variable, but withholds it from Maximin, by insisting that in the framework of a Maximin model this quantity must be fixed in advance.

Since Ben-Haim is aware of these facts, it is astonishing that he continues to propagates misguided arguments about the Info-Gap/Maximin disconnection (eg. A series of Six Lectures on Info-Gap Theory: Decisions Under Severe Uncertainty, Université De Franche-Comté, Besançon, France, October, November, 2008, see abstract;).

The latest version of Ben-Haim's spin on this simple technical matter is this paragraph, taken from the program of the

Workshop on Info-Gap Theory and Its Applications in Design and Strategic Planning

Durham, Monday-Thursday, 17-20 May 2010

" ... Relation between robust-satisficing and min-max. These strategies are interchangeable as tools for describing observed behavior of an agent. However, they can lead to very different choices when used by an agent to select an action, depending on the agent's beliefs. We explain the observational equivalence and behavioral difference between these decision strategies. ..."

An anatomy of the conceptual errors leading to Ben-Haim's choice of a wrong (invalid) instance of the general Maximin model are discussed in detail in the paper

Anatomy of a Misguided Maximin formulation of Info-Gap's Robustness Model

Other valid Maximin models for Info-Gap's robustness model can be found in my paper

The Mighty Maximin!

The Situation Room:

As things stand now, the basic facts are these:

  1. In his books Ben-Haim (2001, 2006) claims that Info-Gap Decision is a new decision theory that is radically different from all current theories for decision-making under uncertainty.

    Yet, it is a simple modeling exercise to show that Info-Gap's generic robustness model is a simple instance of Wald's (1945) famous Maximin Model.

    The formal proof consists of approximately 3 lines.

  2. Info-Gap is hailed as a methodology for robust decision-making under severe uncertainty.

    Yet, it is a simple exercise to show that Info-Gap's robustness model actually does not deal with the severity of the uncertainty: it simply takes no notice of it.

    The formal proof consits of approximately 5 lines.

  3. Info-Gap's rhetoric would have us believe that the solutions it generates are robust.

    Yet, it is obvious -- by inspection -- that under conditions of severe uncertainty Info-Gap Decision Theory is a voodoo decision-making theory so that there is no reason to believe that the solutions it generates are robust.

A final word about the Maximin connection: given the simplicity of the proof and the transparent recipe that it provides for translating Info-Gap's generic model into an equivalent Maximin model, it is baffling that Info-Gap's robustness model continues to be considered a non-Maximin model.

So, the continuing discussion in the Info-Gap literature on whether Info-Gap is similar to but different from, or different from but similar to, Maximin, is to put it mildly ... amusing.

My experience with Info-Gap over the past four years has confirmed and reinforced my long held views on the importance of mathematical modeling in decision-making, particularly under severe uncertainty.

Indeed, Info-Gap Decision Theory is an excellent example of how wrong things can go due to a failure to appreciate the mathematical modeling aspects of Maximin, Worst-Case Analysis and Severe Uncertainty.


Welcome to Factland

This contribution is dedicated to the Info-Gap people at Wikipedia. They were searching for a formal proof that ....

 

Fact 1: Info-Gap is a simple instance of Wald's Maximin model [1945].

 

Fact 2: Info-Gap does not deal with severe uncertainty: it simply ignores it.

Modern Alchemy, Freudian Slips, Quick-Fixes and Suchlike

If you are taking it for granted that the quest for a magic formula capable of transforming severe lack of knowledge / information into substantial knowledge was abandoned with the Enlightenment, I have news for you!

Apparently, against all scientific odds, Info-Gap scholars were successful in imputing likelihood and chanceto results generated by a non-probabilistic model that is completely devoid of any notion of likelihood!

Recall that Info-Gap decision theory prides itself on being non-probabilistic and likelihood-free. Yet, Info-gap scholars -- the Father of Info-Gap included -- now claim that Info-Gap's robustness model is capable of identifying decisions that are most likely to satisfy a given performance requirement.

Consider for instance the following quotes (emphasis is mine):

Information-gap (henceforth termed 'info-gap') theory was invented to assist decision-making when there are substantial knowledge gaps and when probabilistic models of uncertainty are unreliable (Ben-Haim 2006). In general terms, info-gap theory seeks decisions that are most likely to achieve a minimally acceptable (satisfactory) outcome in the face of uncertainty, termed robust satisficing. It provides a platform for comprehensive sensitivity analysis relevant to a decision.

Burgman, Wintle, Thompson, Moilanen, Runge, and Ben-Haim (2008, p. 8).
Reconciling uncertain costs and benefits in Bayes nets for invasive species management
ACERA Endorsed Core Material: Final Report, Project 0601 - 0611, July 2008.
(PDF file, Downloaded on March 21, 2009)

However, if they are uncertain about this model and wish to minimize the chance of unacceptably large costs, they can calculate the robust–optimal number of surveys with eqn 5.

Tracy M. Rout, Colin J. Thompson, and Michael A. McCarthy (2009, p. 785)
Robust decisions for declaring eradication of invasive species
Journal of Applied Ecology 46, 782–786.

This is a major scientific breakthrough!

For, until now we have been warned repeatedly by Info-Gap scholars that no likelihood must be attributed to results generated by Info-Gap decision models. Indeed, we have been advised that this would be deceptive and even dangerous (emphasis is mine):

However, unlike in a probabilistic analysis, r has no connotation of likelihood. We have no rigorous basis for evaluating how likely failure may be; we simply lack the information, and to make a judgment would be deceptive and could be dangerous. There may definitely be a likelihood of failure associated with any given radial tolerance. However, the available information does not allow one to assess this likelihood with any reasonable accuracy.

Ben-Haim (1994, p. 152)
Convex models of uncertainty: applications and implications
Erkenntnis, 4, 139-156.

This point is also made crystal clear in the second edition of the Info-Gap book (emphasis is mine):

In info-gap set models of uncertainty we concentrate on cluster-thinking rather than on recurrence or likelihood. Given a particular quantum of information, we ask: what is the cloud of possibilities consistent with this information? How does this cloud shrink, expand and shift as our information changes? What is the gap between what is known and what could be known. We have no recurrence information, and we can make no heuristic or lexical judgments of likelihood.

Ben-Haim (2006, p. 18)
Info-Gap Decision Theory: Decisions Under Severe uncertainty
Academic Press.

So the question is: have Info-gap scholars managed to accomplish a major feat in the area of decision-making under severe uncertainty?

Of course the answer is that this new claims (Burgman et al. 2008, Rout et al. 2009) are not due to a breakthrough in decision-making under severe uncertainty, but rather to a serious misrepresentation of Info-gap’s robustness model, culminating in a thoroughly incorrect representation of the results.

My view on these episode -- based as it is on numerous discussions with Info-Gap scholars over the past five years -- is that these new claims are simply -- but not surprisingly -- ... Freudian slips.

The point is that -- see my FAQs about Info-Gap -- without imputing some sort of "likelihood" to Info-Gap's decision model, Info-Gap decision theory is, and cannot escape being, a voodoo decision theory.

So, all that these Freudian slips manage to do is to extend the already existing error -- an alternative that some Info-Gap scholars seem to prefer to an admission to a mistake.

It is interesting to note, though, that some Info-Gap scholars have taken note of my criticism of Info-Gap's robustness analysis to the effect that they now introduce an assumption that explicitly imputes "likelihood" to Info-Gap's uncertainty model. For instance, consider this (emphasis is mine):

An assumption remains that values of u become increasingly unlikely as they diverge from û.

Hall, J. and Harvey, H. (2009, p. 2)
Decision making under severe uncertainty for flood risk management: a case study of info-gap robustness analysis.
Eighth International Conference on Hydroinformatics
(January 12-16, 2009, Concepcion, Chile)
(PDF file)

Although this attempt at a quick-fix fails to fix the problem (see FAQ # 78), it does attest to a recognition that without such an assumption, conducting an analysis of the kind prescribed by Info-Gap's robustness model is utterly senseless.

One can only wonder then: how long will it take other Info-Gap scholars such as Burgman et al. (2008) and Rout et al. (2009) to reach this unavoidable conclusion?

Only time will tell (March 21, 2009).

Postscript:

The good news is that I am extremely pleased that, apparently for the first time, an official Government commissioned report takes notice of my criticism of Info-Gap decision theory.

This is long overdue!

Sadly, it is not an Aussie report!

As they say,

You can't be a prophet in your own land!

What a pity!

What a waste!

I hope that AU government agencies that sponsor info-gap projects will soon follow suit and re-examine this voodoo decision theory.

This is long overdue.

More important: I hope that senior academics promoting this theory in Australia and elsewhere will reconsider their position, especially insofar as supervising PhD students on this subject.

This is long overdue!

In any case, the following paragraph is a quote from page 75 of the 2009 Department for Environment Food and Rural Affairs (DEFRA) report:

More recently, Info-Gap approaches that purport to be non-probabilistic in nature developed by Ben-Haim (2006) have been applied to flood risk management by Hall and Harvey (2009). Sniedovich (2007) is critical of such approaches as they adopt a single description of the future and assume alternative futures become increasingly unlikely as they diverge from this initial description. The method therefore assumes that the most likely future system state is known a priori. Given that the system state is subject to severe uncertainty, an approach that relies on this assumption as its basis appears paradoxical, and this is strongly questioned by Sniedovich (2007).

Mervyn Bramley, Ben Gouldby, Anthony Hurford, Jaap-Jeroen Flikweert
Marta Roca Collell, Paul Sayers, Jonathan Simm, Michael Wallis
Delivering Benefits Through Evidence
PAMS (Performance-based Asset Management System)
Phase 2 Outcome Summary Report (PDF File)
Project: SC040018/R1
Environment Agency -- December 2009
Department for Environment Food and Rural Affairs
UK

The diplomatic language of the report cannot veil the obvious fact: Info-Gap decision theory is a voodoo theory!

But, .... if the flaws are so obvious, how is it that senior academics continue to promote this paradoxical, voodoo theory?

Hence, ... my campaign is still on!

The Black Swan

 

Only time will tell what impact (if any) Nassim Taleb's recent popular and controversial book The Black Swan: The Impact of the Highly Improbable will have on the field of decision-making under severe uncertainty.

I, for one, hope that the issues raised in this book and in its predecessor, Fooled by Randomness: The Hidden Role of Chance in the Markets and in Life, will be instrumental in helping decision-makers to identify voodoo decision theories -- such as Info-Gap decision theory -- that promise robust decisions under severe uncertainty.

I fear though -- in view of my experience of the past 40 years - that the danger is that the huge success of the Black Swan will inspire a new wave of voodoo decision theories, purportedly capable of ... "domesticating" black swans and preempting the discovery of ... purple swans!

We shall have to wait and see.

For those who have "been in hiding" I should note that Taleb has become quite a celebrity. According to the Prudent Investor Newsletters (Tuesday, June 3, 2008):

  • Mr. Taleb charges about $60,000 per speaking engagement and does about 30 presentations a year to "to bankers, economists, traders, even to Nasa, the US Fire Administration and the Department of Homeland Security" according to Timesonline’s Bryan Appleyard.

  • He recently got $4million as advance payment for his next much awaited book.

  • Earned $35-$40 MILLION on a huge Black Swan event-on the biggest stockmarket crash in modern history-Black Monday, October 19,1987.

So, if you haven’t heard him in person you can easily find on the WWW numerous videos of his interviews.

Here is a link to a very short (2:45 min) clip, recorded by Taleb himself, apparently at Heathrow Airport, of 10 tips on how to deal with Black Swans, and life in general.

  1. Scepticism is effortful and costly. It is better to be sceptical about matters of large consequences, and be imperfect, foolish and human in the small and the aesthetic.

  2. Go to parties. You can't even start to know what you may find on the envelope of serendipity. If you suffer from agoraphobia, send colleagues.

  3. It's not a good idea to take a forecast from someone wearing a tie. If possible, tease people who take themselves and their knowledge too seriously.

  4. Wear your best for your execution and stand dignified. Your last recourse against randomness is how you act -- if you can't control outcomes, you can control the elegance of your behaviour. You will always have the last word.

  5. Don't disturb complicated systems that have been around for a very long time. We don't understand their logic. Don't pollute the planet. Leave it the way we found it, regardless of scientific 'evidence'.

  6. Learn to fail with pride -- and do so fast and cleanly. Maximise trial and error -- by mastering the error part.

  7. Avoid losers. If you hear someone use the words 'impossible', 'never', 'too difficult' too often, drop him or her from your social network. Never take 'no' for an answer (conversely, take most 'yeses' as 'most probably').

  8. Don't read newspapers for the news (just for the gossip and, of course, profiles of authors). The best filter to know if the news matters is if you hear it in cafes, restaurants ... or (again) parties.

  9. Hard work will get you a professorship or a BMW. You need both work and luck for a Booker, a Nobel or a private jet.

  10. Answer e-mails from junior people before more senior ones. Junior people have further to go and tend to remember who slighted them.

It is interesting to juxtapose Prof. Taleb’s thesis in The Black Swan that severe uncertainty makes (reliable) prediction in the Socio/economic/political spheres impossible, with the polar position taken by his colleague, Prof. Bruce Bueno de Mesquita, who actually specializes in predicting the future.

New Nostradamuses

Not only professionals specializing in "decision under uncertainty", but also the proverbial "man in the street", take it for granted that the ability to accurately predict future events is one of the most onerous challenges facing humankind — especially persons in authority, persons responsible for the management of business or economic organizations etc.

A notable exception to this rule is the New _Nostradamus" : Prof. Bruce Bueno de Mesquita, a political science professor at New York University and Senior Fellow at the Hoover Institution.

Who, according to Good Magazine, specializes in predicting future events — at least in the area of international conflicts.

The claim is that this distinguished political scientist can actually predict the outcome of any international conflcit!

To do this Prof. Bueno de Mesquita does not use a Crystal Ball, but a thoroughly scientific method which he claims, is based in a branch of applied mathematics called Game Theory.

According to GoodReads.com,

" ... Bruce Bueno de Mesquita is a political scientist, professor at New York University, and senior fellow at the Hoover Institution. He specializes in international relations, foreign policy, and nation building. He is also one of the authors of the selectorate theory.

He has founded a company, Mesquita & Roundell, that specializes in making political and foreign-policy forecasts using a computer model based on game theory and rational choice theory. He is also the director of New York University's Alexander Hamilton Center for Political Economy.

He was featured as the primary subject in the documentary on the History Channel in December 2008. The show, titled Next Nostradamus, details how the scientist is using computer algorithms to predict future world events ..."

Here is an interview with Prof. Bueno de Mesquita (with Riz Khan - The art and science of prediction - 09 Jan 08):


And here is a 20-minute lecture on the ... future of Iran (TED, February 2009):

Apparently, all you need to accomplish this is a computer, expert-knowledge on Iran, and game theory!

Some of the predictions attributed to Prof. Bueno de Mesquita are:

  1. The second Palestinian Intifada and the death of the Mideast peace process, two years before this came to pass.

  2. The succession of the Russian leader Leonid Brezhnev by Yuri Andropov, who at the time was not even considered a contender.

  3. The voting out of office of Daniel Ortega and the Sandanistas in Nicaragua, two years before this happened.

  4. The harsh crack down on dissidents by China's hardliners four months before the Tiananmen Square incident.

  5. France's hairs-breadth passage of the European Union's Maastricht Treaty.

  6. The exact implementation of the 1998 Good Friday Agreement between Britain and the IRA.

  7. China's reclaiming of Hong Kong and the exact manner the handover would take place, 12 years before it happened.

Impressive, isn't it!

As might be expected, these and similar claims by Prof. Bueno de Mesquita have sparked a vigorous debate not only in the professional journals but also on the WWW. Interested readers can consult this material to see for themselves, whether Bueno de Mesquita's claims attest to a major scientific breakthrough or ... voodoo mathematics.

Also, in addition to consulting this material you may want to have a look at a short video clip by Matt Brawn (right) which, he compiled in response to a short note entitled This man can actually predict the future!.

Of particular interest is, of course, the "success" rate of the Prof. Bueno de Mesquita's predictions: over 90% — yes over ninty percent!

Here is Trevor Black's common sense reaction to this claim:

I am a little skeptical about anyone who claims to have a 90% success rate. I just don't buy it. Especially when they say that they can explain away a lot of the other 10%.

If you come to me and tell me you have a model that gets it right 60% or 70% of the time, I may listen. Skeptically, but I will listen. 90% and I start to smell something.

All I wish to add here is that Prof. Bueno de Mesquita (left) makes his predictions under conditions of "severe uncertainty" which of course render them hugely vulnerable to what Prof. Naseem Taleb (right) dubs the Black Swan phenomenon.

Hence, the very proposition that such predictions can be made at all, let alone be reliable, is diametrically opposed to Nassim Taleb's categorical rejection of any such position. For his thesis is that Black Swans are totally outside the purview of mathematical treatment, especially by models that are based on expected utility theory and rational choice theory.

Interesting, though, this is precisely the stuff that Prof. Bueno de Mesquita's method is made of: expected utility theory and rational choice theory!

Even more interesting is the fact that Nassim Taleb (right) and Bueno de Mesquita (left) are staff members of the same academic institution, namely New York University. So, all that's left to say is: Go figure!

As indicated above, the debate over Bueno de Mesquita's theories is not new. It has been ongoing, in the relevant academic literature, at least since the publication of his book The War Trap (1981).

For an idea of the kind of criticism sparked by his work, take a look at the quotes I provide from articles that are critical of Bueno de Mesquita theories.

Of course, there are other New Nostradamuses around.

According to the Associated Press, the latest (Mar 4, 4:39 AM EST) news from Russia about the future of the USA is that

" ... President Barack Obama will order martial law this year, the U.S. will split into six rump-states before 2011, and Russia and China will become the backbones of a new world order ..."

Apparently this prediction was made by Igor Panarin (right), Dean of the Russian Foreign Ministry diplomatic academy and a regular on Russia's state-controlled TV channels (see full AP news report).

Regarding the future of Russia,

"You don't sound too hopeful".
"Hopeful? Please, I am Russian. I live in a land of mad hopes, long queues, lies and humiliations. They say about Russia we never had a happy present, only a cruel past and a quite amazing future ..."
Malcolm Bradbury
To the Hermitage (2000, p. 347)

We should therefore be reminded of J K Galbraith's (1908-2006) poignant observation:

There are two classes of forecasters: those who don't know and those who don't know they don't know.

And in the same vein,

The future is just what we invent in the present to put an order over the past.

Malcolm Bradbury
Doctor Criminale (1992, p. 328)

So, we shall have to wait and see.

And how about this more recent piece by Heath Gilmore and Brian Robins in the Sydney Morning Herald (March 27, 2009):

"... COUPLES wondering if the love will last could find out if theirs is a match made in heaven by subjecting themselves to a mathematical test.

A professor at Oxford University and his team have perfected a model whereby they can calculate whether the relationship will succeed.

In a study of 700 couples, Professor James Murray, a maths expert, predicted the divorce rate with 94 per cent accuracy.

His calculations were based on 15-minute conversations between couples who were asked to sit opposite each other in a room on their own and talk about a contentious issue, such as money, sex or relations with their in-laws.

Professor Murray and his colleagues recorded the conversations and awarded each husband and wife positive or negative points depending on what was said. ..."

Such interviews should perhaps be made mandatory for all couples registering their marriage.

More details on the mathematics of marriage can be found in The Mathematics of Marriage: Dynamic Nonlinear Models by J.M. Gottman, J.D. Murray, C. Swanson, R. Tyson, and K.R. Swanson (MIT Press, Cambridge, MA, 2002.)


On a more positive note, though, here is an online Oracle from Melbourne (Australia: the land of the real Black Swan!).

You may wish to consult this friendly 24/7 facility about important "Yes/No" questions that you no doubt have about the future.

Enter your "Yes/No" question:
    

 
 

More on this and related topics can be found in the pages of the Worst-Case Analysis / Maximin Campaign, Severe Uncertainty, and the Info-Gap Campaign.

Recent Articles, Working Papers, Notes

Also, see my complete list of articles
  • Sniedovich, M., (2010) A classic decision theoretic perspective on worst-case analysis, Applications of Mathematics, in press.

  • Sniedovich, M., (2010) Black swans, new Nostradamuses, voodoo decision theories and the science of decision-making in the face of severe uncertainty, International Transactions in Operations Research, in press.

  • Sniedovich, M., (2010) A bird's view of Info-Gap decision theory, Journal of Risk Finance, 11(3), 268-283.

  • Sniedovich, M. (2010) Dynamic programming: introductory concepts, in Wiley Encyclopedia of Operations Research and Management Science (EORMS), Wiley, in press.

  • Sniedovich, M., (2010) Dynamic Programming: Foundations and Principles, Second Edition,, Francis and Taylor, in press.

  • Caserta, M., Voss, S., Sniedovich, M. (2010) Applying the corridor method to a blocks relocation problem, OR Spectrum, in press.

  • Sniedovich M. (2009) Modeling of robustness against severe uncertainty, pp. 33- 42, Proceedings of the 10th International Symposium on Operational Research, SOR'09, Nova Gorica, Slovenia, September 23-25, 2009.

  • Sniedovich M. (2009) A Critique of Info-Gap Robustness Model. In: Martorell et al. (eds), Safety, Reliability and Risk Analysis: Theory, Methods and Applications, pp. 2071-2079, Taylor and Francis Group, London.
    • .
  • Sniedovich M. (2009) A Classical Decision Theoretic Perspective on Worst-Case Analysis, Working Paper No. MS-03-09, Department of Mathematics and Statistics, The University of Melbourne, (PDF File)

  • Caserta, M., Voss, S., Sniedovich, M. (2008) The corridor method - A general solution concept with application to the blocks relocation problem. In: A. Bruzzone, F. Longo, Y. Merkuriev, G. Mirabelli and M.A. Piera (eds.), 11th International Workshop on Harbour, Maritime and Multimodal Logistics Modeling and Simulation, DIPTEM, Genova, 89-94.

  • Sniedovich, M. (2008) FAQS about Info-Gap Decision Theory, Working Paper No. MS-12-08, Department of Mathematics and Statistics, The University of Melbourne, (PDF File)

  • Sniedovich, M. (2008) A Call for the Reassessment of the Use and Promotion of Info-Gap Decision Theory in Australia (PDF File)

  • Sniedovich, M. (2008) Info-Gap decision theory and the small applied world of environmental decision-making, Working Paper No. MS-11-08
    This is a response to comments made by Mark Burgman on my criticism of Info-Gap (PDF file )

  • Sniedovich, M. (2008) A call for the reassessment of Info-Gap decision theory, Decision Point, 24, 10.

  • Sniedovich, M. (2008) From Shakespeare to Wald: modeling wors-case analysis in the face of severe uncertainty, Decision Point, 22, 8-9.

  • Sniedovich, M. (2008) Wald's Maximin model: a treasure in disguise!, Journal of Risk Finance, 9(3), 287-291.

  • Sniedovich, M. (2008) Anatomy of a Misguided Maximin formulation of Info-Gap's Robustness Model (PDF File)
    In this paper I explain, again, the misconceptions that Info-Gap proponents seem to have regarding the relationship between Info-Gap's robustness model and Wald's Maximin model.

  • Sniedovich. M. (2008) The Mighty Maximin! (PDF File)
    This paper is dedicated to the modeling aspects of Maximin and robust optimization.

  • Sniedovich, M. (2007) The art and science of modeling decision-making under severe uncertainty, Decision Making in Manufacturing and Services, 1-2, 111-136. (PDF File) .

  • Sniedovich, M. (2007) Crystal-Clear Answers to Two FAQs about Info-Gap (PDF File)
    In this paper I examine the two fundamental flaws in Info-Gap decision theory, and the flawed attempts to shrug off my criticism of Info-Gap decision theory.

  • My reply (PDF File) to Ben-Haim's response to one of my papers. (April 22, 2007)

    This is an exciting development!

    • Ben-Haim's response confirms my assessment of Info-Gap. It is clear that Info-Gap is fundamentally flawed and therefore unsuitable for decision-making under severe uncertainty.

    • Ben-Haim is not familiar with the fundamental concept point estimate. He does not realize that a function can be a point estimate of another function.

      So when you read my papers make sure that you do not misinterpret the notion point estimate. The phrase "A is a point estimate of B" simply means that A is an element of the same topological space that B belongs to. Thus, if B is say a probability density function and A is a point estimate of B, then A is a probability density function belonging to the same (assumed) set (family) of probability density functions.

      Ben-Haim mistakenly assumes that a point estimate is a point in a Euclidean space and therefore a point estimate cannot be say a function. This is incredible!


  • A formal proof that Info-Gap is Wald's Maximin Principle in disguise. (December 31, 2006)
    This is a very short article entitled Eureka! Info-Gap is Worst Case (maximin) in Disguise! (PDF File)
    It shows that Info-Gap is not a new theory but rather a simple instance of Wald's famous Maximin Principle dating back to 1945, which in turn goes back to von Neumann's work on Maximin problems in the context of Game Theory (1928).

  • A proof that Info-Gap's uncertainty model is fundamentally flawed. (December 31, 2006)
    This is a very short article entitled The Fundamental Flaw in Info-Gap's Uncertainty Model (PDF File) .
    It shows that because Info-Gap deploys a single point estimate under severe uncertainty, there is no reason to believe that the solutions it generates are likely to be robust.

  • A math-free explanation of the flaw in Info-Gap. ( December 31, 2006)
    This is a very short article entitled The GAP in Info-Gap (PDF File) .
    It is a math-free version of the paper above. Read it if you are allergic to math.

  • A long essay entitled What's Wrong with Info-Gap? An Operations Research Perspective (PDF File) (December 31, 2006).
    This is a paper that I presented at the ASOR Recent Advances in Operations Research (PDF File) mini-conference (December 1, 2006, Melbourne, Australia).

Recent Lectures, Seminars, Presentations

If your organization is promoting Info-Gap, I suggest that you invite me for a seminar at your place. I promise to deliver a lively, informative, entertaining and convincing presentation explaining why it is not a good idea to use — let alone promote — Info-Gap as a decision-making tool.

Here is a list of relevant lectures/seminars on this topic that I gave in the last two years.

Disclaimer: This page, its contents and style, are the responsibility of the author (Moshe Sniedovich) and do not represent the views, policies or opinions of the organizations he is associated/affiliated with.


Last modified: Friday, 30-Jul-2010 23:25:29 MST