Philosophy of Statistics

“You May Believe You Are a Bayesian But You Are Probably Wrong”

The following is an extract (58-63) from the contribution by

Stephen Senn  (Full article)

Head of the Methodology and Statistics Group,

Competence Center for Methodology and Statistics (CCMS), Luxembourg

…..

I am not arguing that the subjective Bayesian approach is not a good one to use.  I am claiming instead that the argument is false that because some ideal form of this approach to reasoning seems excellent in theory it therefore follows that in practice using this and only this approach to reasoning is the right thing to do.  A very standard form of argument I do object to is the one frequently encountered in many applied Bayesian papers where the first paragraphs lauds the Bayesian approach on various grounds, in particular its ability to synthesize all sources of information, and in the rest of the paper the authors assume that because they have used the Bayesian machinery of prior distributions and Bayes theorem they have therefore done a good analysis. It is this sort of author who believes that he or she is Bayesian but in practice is wrong. (58) Continue reading

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Part II: Breaking Through the Breakthrough* (please start with Dec 6 post)

This is a first draft of part II of the presentation begun in the December 6 blog post.  This completes the proposed presentation. I expect errors, and I will be grateful for feedback! (NOTE: I did not need to actually rip a cover of EGEK to obtain this effect!)

SEVEN:NOW FOR THE BREAKTHROUGH

You have observed y”, the .05 significant result from E”,the optional stopping rule, ending at n = 100.

Birnbaum claims he can show that you, as a frequentist error statistician, must grant that it is equivalent to having fixed n= 100 at the start (i.e., experiment E’)

Reminder:

The (strong) LikelihoodPrinciple (LP) is a universal conditional claim:

If two data sets y’and y” from experiments E’ and E” respectively, have likelihood functions which are functions of the same parameter(s) µ

and are proportional to each other, then y’ and y”should lead to identical inferential conclusions about µ Continue reading

Categories: Birnbaum Brakes, Likelihood Principle | 2 Comments

Putting the Brakes on the Breakthrough Part I*

brakes on the 'breakthrough'

brakes on the ‘breakthrough’

I am going to post a FIRST draft (for a brief presentation next week in Madrid).  [I thank David Cox for the idea!] I expect errors, and I will be very grateful for feedback!  This is part I; part II will be posted tomorrow.  These posts may disappear once I’ve replaced them with a corrected draft.  I’ll then post the draft someplace.

If you wish to share queries/corrections please post as a comment or e-mail: error@vt.edu.  (ignore Greek symbols that are not showing correctly, I await fixes by Elbians.) Thanks much!

ONE: A Conversation between Sir David Cox and D. Mayo (June, 2011)

Toward the end of this exchange, the issue of the Likelihood Principle (LP)[1] arose:

COX: It is sometimes claimed that there are logical inconsistencies in frequentist theory, in particular surrounding the strong Likelihood Principle (LP). I know you have written about this, what is your view at the moment.

MAYO: What contradiction?
COX: Well, that frequentist theory does not obey the strong LP. Continue reading

Categories: Birnbaum Brakes, Likelihood Principle | Tags: , | 5 Comments

Getting Credit (or blame) for Something You Don’t Deserve (and first honorable mention)

Ruler at the Bottom of Ocean
It was three months ago that I began this blog with “overheard at the comedy hour at the Bayesian retreat” …and we’re not at near the end of the repertoire of jokes   This last, in effect, accuses the frequentist error-statistical account of licensing the following (make-believe) argument after the oil spill in the Gulf of Mexico in 2010:
Oil Exec: We had highly reliable evidence that H: the pressure was at normal levels on April 20, 2010!

Senator: But you conceded that whenever your measuring tool showed dangerous or ambiguous readings, you continually lowered the pressure, and that the stringent “cement bond log” test was entirely skipped. Continue reading

Categories: Comedy, Philosophy of Statistics | Tags: , , | 2 Comments

RMM-5: Special Volume on Stat Scie Meets Phil Sci

The article “Low Assumptions, High Dimensions” by Larry Wasserman has now been published in our special volume of the on-line journal, Rationality, Markets, and Morals (Special Topic: Statistical Science and Philosophy of Science: Where Do/Should They Meet?)

Abstract:
These days, statisticians often deal with complex, high dimensional datasets. Researchers in statistics and machine learning have responded by creating many new methods for analyzing high dimensional data. However, many of these new methods depend on strong assumptions. The challenge of bringing low assumption inference to high dimensional settings requires new ways to think about the foundations of statistics. Traditional foundational concerns, such as the Bayesian versus frequentist debate, have become less important.

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RMM-4: Special Volume on Stat Scie Meets Phil Sci

The article “Foundational Issues in Statistical Modeling: Statistical Model Specification and Validation*” by Aris Spanos has now been published in our special volume of the on-line journal, Rationality, Markets, and Morals (Special Topic: Statistical Science and Philosophy of Science: Where Do/Should They Meet?”)

Abstract:
Statistical model specification and validation raise crucial foundational problems whose pertinent resolution holds the key to learning from data by securing the reliability of frequentist inference. The paper questions the judiciousness of several current practices, including the theory-driven approach, and the Akaike-type model selection procedures, arguing that they often lead to unreliable inferences. This is primarily due to the fact that goodness-of-fit/prediction measures and other substantive and pragmatic criteria are of questionable value when the estimated model is statistically misspecified. Foisting one’s favorite model on the data often yields estimated models which are both statistically and substantively misspecified, but one has no way to delineate between the two sources of error and apportion blame. The paper argues that the error statistical approach can address this Duhemian ambiguity by distinguishing between statistical and substantive premises and viewing empirical modeling in a piecemeal way with a view to delineate the various issues more effectively. It is also argued that Hendry’s general to specific procedures does a much better job in model selection than the theory-driven and the Akaike-type procedures primary because of its error statistical underpinnings.

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RMM-3: Special Volume on Stat Scie Meets Phil Sci

The article “Empirical Economic Model Discovery and Theory Evaluation” by Sir David Hendry has now been published in our special volume of the on-line journal, Rationality, Markets, and Morals (Special Topic: Statistical Science and Philosophy of Science: Where Do/Should They Meet?”)

Abstract: 
Economies are so high dimensional and non-constant that many features of models can- not be derived by prior reasoning, intrinsically involving empirical discovery and requiring theory evaluation. Despite important differences, discovery and evaluation in economics are similar to those of science. Fitting a pre-specified equation limits discovery, but automatic methods can formulate much more general initial models with many possible variables, long lag lengths and non-linearities, allowing for outliers, data contamination, and parameter shifts; then select congruent parsimonious-encompassing models even with more candidate variables than observations, while embedding the theory; finally rigorously evaluate selected models to ascertain their viability.

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ReBlogging the Likelihood Principle #2: Solitary Fishing:SLP Violations

Reblogging from a year ago. The Appendix of the “Cox/Mayo Conversation” (linked below [i]) is an attempt to quickly sketch Birnbaum’s argument for the strong likelihood principle (SLP), and its sins.  Couple of notes: Firstly, I am a philosopher (of science and statistics) not a statistician.  That means, my treatment will show all of the typical (and perhaps annoying) signs of being a trained philosopher-logician.  I’ve no doubt statisticians would want to use different language, which is welcome.  Second, this is just a blog (although perhaps my published version is still too informal for some). Continue reading

Categories: Likelihood Principle | Tags: , , | 9 Comments

RMM-2: "A Conversation Between Sir David Cox & D.G. Mayo"

Published today in Rationality, Markets and Morals

Studies at the Intersection of Philosophy and Economics

 “A Statistical Scientist Meets a Philosopher of Science: A Conversation between Sir David Cox and Deborah Mayo”

(as recorded, June, 2011)

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RMM-1: Special Volume on Stat Sci Meets Phil Sci

Little by little the articles on Stat Sci Meets Phil Sci are appearing in “Rationality, Markets and Morals,”  online.

The article “Statistical Science and Philosophy of Science: Where Do/Should They Meet in 2011 (and Beyond)?” has now been published.

Categories: philosophy of science, Philosophy of Statistics, Statistics | Tags: , | 4 Comments

Blogging the (Strong) Likelihood Principle

I am guilty of not having provided the detailed responses that are owed to the several entries in Christian Robert’s blog on Mayo and Spanos (eds.), ERROR AND INFERENCE: Recent Exchanges on Experimental Reasoning Reliability, and the Objectivity and Rationality of Science (E.R.R.O.R.S.)  (2010, CUP).  Today, I couldn’t resist writing a (third) follow-up comment having to do with my argument on the (strong) Likelihood Principle, even though I wasn’t planning to jump into that issue on this blog just yet. Having been lured to react, and even sketch the argument, I direct interested readers to his blog:

http://xianblog.wordpress.com/

As you can guess, hard copies of our book play a useful role in propping open doors to breeze through marble floors in a wheelchair!  Since I’m nearly free of it (thanks to the ministrations of the recovery team here at Chatfield Chateau), a picture seemed in order!

For an interesting, longish review of the book that I just encountered by Adam La Caze (Note Dame Philosophical Reviews) see: http://ndpr.nd.edu/news/24435-error-and-inference-recent-exchanges-on-experimental-reasoning-reliability-and-the-objectivity-and-rationality-of-science/

Categories: Likelihood Principle, Statistics | Tags: , , | Leave a comment

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