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House Committee asks Mann to show his work

Diamond

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Mann Hockey Stick: Latest news

The House of Representatives' Committee on Energy and Commerce has written to Drs Mann, Bradley and Hughes demanding that they disclose all materials including computer source code, that was used to produce MBH98 (the "Hockey Stick") that was featured prominently in the IPCC's Third Assessment Report (TAR) in 2001 and reported around the world.

http://energycommerce.house.gov/108/Letters/06232005_1570.htm

Dear Dr. Mann:
Questions have been raised, according to a February 14, 2005 article in The Wall Street
Journal, about the significance of methodological flaws and data errors in your studies of the
historical record of temperatures and climate change. We understand that these studies of
temperature proxy records (tree rings, ice cores, corals, etc.) formed the basis for a new finding in
the 2001 United Nation’s Intergovernmental Panel on Climate Change (IPCC) Third Assessment
Report (TAR). This finding – that the increase in 20th century northern hemisphere temperatures is
“likely to have been the largest of any century during the past 1,000 years” and that the “1990s was
the warmest decade and 1998 the warmest year” – has since been referenced widely and has become
a prominent feature of the public debate surrounding climate change policy.

However, in recent peer-reviewed articles in Science, Geophysical Research Letters, and Energy
& Environment, researchers question the results of this work. As these researchers find, based on the
available information, the conclusions concerning temperature histories – and hence whether
warming in the 20th century is actually unprecedented – cannot be supported by the Mann et al.
studies cited in the TAR. In addition, we understand from the February 14 Journal and these other
reports that researchers have failed to replicate the findings of these studies, in part because of
problems with the underlying data and the calculations used to reach the conclusions. Questions
have also been raised concerning the sharing and dissemination of the data and methods used to
perform the studies. For example, according to the January 2005 Energy & Environment, such
information necessary to replicate the analyses in the studies has not been made fully available to
researchers upon request
Click to expand...

So the committee requests full disclosure (with my added emphasis):

To assist us as we begin this review, and pursuant to Rules X and XI of the U.S. House of
Representatives, please provide the following information requested below on or before July 11,
2005:
1. Your curriculum vitae, including, but not limited to, a list of all studies relating to climate
change research for which you were an author or co-author and the source of funding for
those studies.
2. List all financial support you have received related to your research, including, but not
limited to, all private, state, and federal assistance, grants, contracts (including subgrants
or subcontracts), or other financial awards or honoraria.
3. Regarding all such work involving federal grants or funding support under which you
were a recipient of funding or principal investigator, provide all agreements relating to
those underlying grants or funding, including, but not limited to, any provisions,
adjustments, or exceptions made in the agreements relating to the dissemination and
sharing of research results.
4. Provide the location of all data archives relating to each published study for which you
were an author or co-author and indicate: (a) whether this information contains all the
specific data you used and calculations your performed, including such supporting
documentation as computer source code, validation information, and other ancillary
information, necessary for full evaluation and application of the data, particularly for
another party to replicate your research results; (b) when this information was available to
researchers; (c) where and when you first identified the location of this information; (d)
what modifications, if any, you have made to this information since publication of the
respective study; and (e) if necessary information is not fully available, provide a detailed
narrative description of the steps somebody must take to acquire the necessary information
to replicate your study results or assess the quality of the proxy data you used.
5. According to The Wall Street Journal, you have declined to release the exact computer
code you used to generate your results. (a) Is this correct? (b) What policy on sharing
research and methods do you follow? (c) What is the source of that policy? (d) Provide
this exact computer code used to generate your results.
6. Regarding study data and related information that is not publicly archived, what requests
have you or your co-authors received for data relating to the climate change studies, what
was your response, and why?
7. The authors McIntyre and McKitrick (Energy & Environment, Vol. 16, No. 1, 2005)
report a number of errors and omissions in Mann et. al., 1998. Provide a detailed
narrative explanation of these alleged errors and how these may affect the underlying
conclusions of the work, including, but not limited to answers to the following questions:
a. Did you run calculations without the bristlecone pine series referenced in the
article and, if so, what was the result?
b. Did you or your co-authors calculate temperature reconstructions using the
referenced “archived Gaspe tree ring data,” and what were the results?
c. Did you calculate the R2 statistic for the temperature reconstruction, particularly
for the 15th Century proxy record calculations and what were the results?
d. What validation statistics did you calculate for the reconstruction prior to 1820,
and what were the results?
e. How did you choose particular proxies and proxy series?
8. Explain in detail your work for and on behalf of the Intergovernmental Panel on Climate
Change, including, but not limited to: (a) your role in the Third Assessment Report; (b)
the process for review of studies and other information, including the dates of key
meetings, upon which you worked during the TAR writing and review process; (c) the
steps taken by you, reviewers, and lead authors to ensure the data underlying the studies
forming the basis for key findings of the report were sound and accurate; (d) requests you
received for revisions to your written contribution; and (e) the identity of the people who
wrote and reviewed the historical temperature-record portions of the report, particularly
Section 2.3, “Is the Recent Warming Unusual?”
Click to expand...

Of course this is the computer code that Mann told the WSJ he would not be "intimidated" into revealing.

A point of legality and jurisdiction: Is it possible for Mann to not disclose all of this material and not cooperate with the Committee?

The Committee has also sent letters requesting full disclosure to Dr Pachauri, chairman of the IPCC and the director of the National Science Foundation, Arden Bement, asking what the procedures are on review and disclosure and how Mann was allowed to place his own work into the IPCC TAR without independent audit and review.

Looks like we're going to find out the truth about the Hockey Stick for everybody to see.
 
Obfuscation and delaying tactics will likely prevent anything new from appearing for quite a while, and then only if the letters are followed up with a vigorous persuit for the answers.

I don't expect much in the way of actual cooperation from this crowd. Certainly not within the three week time frame cited.

Bob
 
I can't help wondering how members of the committee would cope if asked to provide similar details of their own work.

Still, I can see no legitimate reason why a scientist would not be willing to present the information requested.
 
Diamond said:
A point of legality and jurisdiction: Is it possible for Mann to not disclose all of this material and not cooperate with the Committee?
Click to expand...

I think not. He can refuse to respond as asked but the committee can demand he answer, in person, up front and personal, under oath, sitting there in one of the Washington committee rooms with TV cameras and microphones pointing at him. He doesn't want that.
 
Re: Re: House Committee asks Mann to show his work

Rob Lister said:
I think not. He can refuse to respond as asked but the committee can demand he answer, in person, up front and personal, under oath, sitting there in one of the Washington committee rooms with TV cameras and microphones pointing at him. He doesn't want that.
Click to expand...

I can't help but think that that's what's going to happen anyway. Which would be a shame, wouldn't it? :D
 
A few links on this subject:

Recent Scientific American Article generally supportive of Mann:
http://www.sciam.com/article.cfm?articleID=00007F57-9CE1-1213-9BEF83414B7F0000&pageNumber=1&catID=2

Two articles highly critical of Mann's work with regard to hockey stick graph:

http://www.techcentralstation.com/032304E.html
http://www.technologyreview.com/articles/04/10/wo_muller101504.asp

Mann and others response to criticism of their paper regarding the hockey stick:
http://www.realclimate.org/index.php?p=11

A brief overview of what I got out of these articles :

We only have direct temperature measurement data going back about 150 years. To estimate atmospheric temperatures prior to that so call proxies must be used. Some of these proxies include tree ring growth data, atmospheric gas data from ice cores, and data from coral reefs. Each of the various proxies has significant flaws. Tree ring data is limited to mostly the northern hemisphere (non-polar) and it provides climate data mostly about the summer season. Ice Core data is mostly limited to poles and coral data is limited to the equatorial regions and doesn't go back very far. There is also lack of a scientifc concensus on exactly how to interpret the ice core data.

So Mann's (and others) idea to overcome the weakness of any particular proxy was to integrate all the various proxy data into a simple graph. The result was the famous hockey stick graph. The algorythm used to construct the graph was criticized by McIntyre and McKitrick. Mann answers that criticism in the article I linked to above (and with some other links) but at about this time I ran out of enthusiam for this subject and didn't evaluate either the criticism or the response very well.
 
Soapy Sam said:
Still, I can see no legitimate reason why a scientist would not be willing to present the information requested.
Click to expand...

I can see no legitimate reason for a senator to ask a scientist for:

1. Your curriculum vitae, including, but not limited to, a list of all studies relating to climate
change research for which you were an author or co-author and the source of funding for
those studies.
2. List all financial support you have received related to your research, including, but not
limited to, all private, state, and federal assistance, grants, contracts (including subgrants
or subcontracts), or other financial awards or honoraria.
3. Regarding all such work involving federal grants or funding support under which you
were a recipient of funding or principal investigator, provide all agreements relating to
those underlying grants or funding, including, but not limited to, any provisions,
adjustments, or exceptions made in the agreements relating to the dissemination and
sharing of research results.
4. Provide the location of all data archives relating to each published study for which you
were an author or co-author
Click to expand...

Unless, of course, the Senator was on a fishing expedition in an attempt to find any possible reason to discredit the scientist.

If he was concenrned about a specific paper, he would ask about details germain to the paper, but that's not what is happening here. Let's get this straight, he's not asking for specific information about a single paper, but all possible information about a person (group of people), much of which is not germaine to the paper in question.
 
TonyL said:
I can see no legitimate reason for a senator to ask a scientist for:



Unless, of course, the Senator was on a fishing expedition in an attempt to find any possible reason to discredit the scientist.

If he was concenrned about a specific paper, he would ask about details germain to the paper, but that's not what is happening here. Let's get this straight, he's not asking for specific information about a single paper, but all possible information about a person (group of people), much of which is not germaine to the paper in question.
Click to expand...

I think all the questions are germane. Mann has recieved federal and UN funding and served on state, federal and international scientific advisory boards. It is certainly as fair to examine his qualifications and possible conflicts of interests as it is to examine those of the committee asking the questions. If Mann had revealed his code and data sources in the first place, we wouldn't be discussing this.
 
Rob Lister said:
I think all the questions are germane. Mann has recieved federal and UN funding and served on state, federal and international scientific advisory boards. It is certainly as fair to examine his qualifications and possible conflicts of interests as it is to examine those of the committee asking the questions.
Click to expand...

Is it? My understanding -- as I have quoted elsewhere on this board -- is that, while the biggest fool in the world may say that the sun is shining, that doesn't make it dark out.

If Dr. Mann's data and methods will withstand the sort of fine-toothed scrutiny that they are about to undergo, then it doesn't matter whether he's abstractly qualified or what sort of conflicts of interest he has.

That's one of the beauties of science.

My fear -- and based on the current climate of politics over science in Washington, DC, combined with the tendency of the current administration to demonize anyone with whom they disagree, I think it's a valid fear -- is that this information will be used as a basis for a fishing expedition, to give the committee a chance to reject Mann's conclusions out of hand as a 'fruit of a poisoned tree,' without regard to their scientific merit.

From a scientific epistemological point of view, the only information that the committee really needs is the data that Mann used in his analyses, and the analysis methods that he used, including the computer programs. It really is that simple. Hand the program code (and data) to an appropriate NSF wonk and see if he can verify the validity of the raw data (which should be simple enough), and the validity of the algorithm and code used to process the data.

If the data and code can be validated, then simply re-running the code will either confirm (or not) Dr. Mann's analysis. If the analysis is confirmed, then his c.v. doesn't matter. If the analysis is disconfirmed, then his c.v. still doesn't matter.
 
new drkitten said:
My fear -- and based on the current climate of politics over science in Washington, DC, combined with the tendency of the current administration to demonize anyone with whom they disagree, I think it's a valid fear -- is that this information will be used as a basis for a fishing expedition, to give the committee a chance to reject Mann's conclusions out of hand as a 'fruit of a poisoned tree,' without regard to their scientific merit.
Click to expand...

I share your concern on this. The current administration has a clear and overt history of manipulating and distorting science to it's own ends - and without passing judgement on the merit (or lack thereof) of Mann's findings, his conclusions would make him a prime target for this kind of activity.
 
TonyL said:
Unless, of course, the Senator was on a fishing expedition in an attempt to find any possible reason to discredit the scientist.
Click to expand...

Boring pedantic reply. It's not a Senator who's asking but a Representative (or rather a Committee from the House not the Senate).

Less pedantically,

1. Your curriculum vitae, including, but not limited to, a list of all studies relating to climate
change research for which you were an author or co-author and the source of funding for
those studies.
2. List all financial support you have received related to your research, including, but not
limited to, all private, state, and federal assistance, grants, contracts (including subgrants
or subcontracts), or other financial awards or honoraria.
3. Regarding all such work involving federal grants or funding support under which you
were a recipient of funding or principal investigator, provide all agreements relating to
those underlying grants or funding, including, but not limited to, any provisions,
adjustments, or exceptions made in the agreements relating to the dissemination and
sharing of research results.
4. Provide the location of all data archives relating to each published study for which you
were an author or co-author
Click to expand...

All of this is related to why Mann has refused to disclose his methodology if his work is wholly or mostly publicly funded, and who gets to decide what gets revealed and what doesn't. If there's a fishing expedition going on (and that's an if) then it's looking for conflct of interests and/or breaches of the agreements under which he accepted money from the government via the National Science Foundation.

Since Mann has flat out refused to disclose key pieces of work, then the Committee wants to know on what basis he does so. The Hockey Stick is not the only piece of work that Mann refuses to disclose data, code and methodology.

If he was concerned about a specific paper, he would ask about details germain to the paper, but that's not what is happening here. Let's get this straight, he's not asking for specific information about a single paper, but all possible information about a person (group of people), much of which is not germaine to the paper in question.
Click to expand...

As I say, it's not just a single paper but a group of papers that Mann has co-authored with that is under scrutiny.

Note that the director of the NSF has also been asked about disclosure and what rules he disburses grants under.

I take the point about the worry over the Bush Administration twisting results that it doesn't like, but this is not about political transparency but scientific transparency especially of key pieces of research that underpin public policy, if not in the US then elsewhere.
 
Diamond said:
I take the point about the worry over the Bush Administration twisting results that it doesn't like, but this is not about political transparency but scientific transparency especially of key pieces of research that underpin public policy, if not in the US then elsewhere.
Click to expand...

I sincerely hope you're right. Given the recent dissaffection between Congress and the Administration, I can only hope for a return to representation of diverse interests instead of the current monomaniacal theme...
 
jmercer said:
I sincerely hope you're right. Given the recent dissaffection between Congress and the Administration, I can only hope for a return to representation of diverse interests instead of the current monomaniacal theme...
Click to expand...

I would agree. As someone who disagrees with a great deal with a lot of the policies of the current Administration, I would hope that this sort of investigation sheds light rather than cloaks in secrecy.

All I want to know is the truth, whatever it is. If Mann did his work correctly, then full disclosure is the only way to demonstrate this.
 
Diamond said:

All of this is related to why Mann has refused to disclose his methodology if his work is wholly or mostly publicly funded, and who gets to decide what gets revealed and what doesn't. If there's a fishing expedition going on (and that's an if) then it's looking for conflct of interests and/or breaches of the agreements under which he accepted money from the government via the National Science Foundation.

Since Mann has flat out refused to disclose key pieces of work, then the Committee wants to know on what basis he does so. The Hockey Stick is not the only piece of work that Mann refuses to disclose data, code and methodology.
Click to expand...

Yes, but why?

I can think of several dozen reasons why a researcher might refuse to disclose his methods -- some legitimate, some less so, and some that would be regarded as reason for chemical intervention by the appropriate clinical authorities. But so what?

If Dr. Mann's results are valid, then they are valid irrespective of conflicts of interest or breaches of contract. Obviously, the only way to know if his results are valid is to examine his methods, which the committee is asking to do. But his contractual obligations are irrelevant to the question of whether his methods are sound.

I find it helpful to look at these situations through the lens of case analysis. There are two possibilities for his results : they either stand up or they don't. Similarly, there are two possiblities for his professional ethics : they are either acceptable, or they aren't. We thus have four possibilities:

  1. He's an honest scientist with legitimate results
  2. He's a dishonest schnook, but with legitimate results
  3. He's an honest but incompetent scientist with invalid results
  4. He's a dishonest weasel with invalid results.
    [/list=1]

    Obviously, if cases 3 or 4 hold, then his findings should not be the basis for public policy. Similarly, if case 1 holds, then his findings should be the basis for public policy.

    But what about case 2? As a scientist, I would like to believe that if his results are valid, public policy should take them into account, even if he's a drug-addicted wife-beater who has defrauded the National Science Foundation out of millions of illegally-obtained dollars. Because no matter what you say about his ethics, if he is correct about the causes and nature of global warming, then it is to be taken seriously.

    I fear, however, that the government is of the opinion that in the event of case 2, they can ignore the legitimate findings by killing the messenger. I further fear that they are planning to find some fault to make sure that Dr. Mann appears to be dishonest regardless of the actual facts of the case. I fear he's being summoned before a kangaroo court that has already determined that he is guilty, and that they are simply searching for the evidence that will show what they already "know" to be the case.
 
new drkitten said:
Yes, but why?

I can think of several dozen reasons why a researcher might refuse to disclose his methods -- some legitimate, some less so, and some that would be regarded as reason for chemical intervention by the appropriate clinical authorities. But so what?
Click to expand...

I'd love to know what those "several dozen reasons" were..other than for national security or to protect a commercial secret. But we're talking about climate science here.

If Dr. Mann's results are valid, then they are valid irrespective of conflicts of interest or breaches of contract. Obviously, the only way to know if his results are valid is to examine his methods, which the committee is asking to do. But his contractual obligations are irrelevant to the question of whether his methods are sound.
Click to expand...

As I wrote, the question of whether the methodology and source code should be revealed is a question for the funding authorities, and as the Committee is in the position of speaking on behalf of the taxpayers, it is asking "who authorized the non-disclosure and why?" That's why the director the NSF is also asked about those rules regarding disclosure.

I find it helpful to look at these situations through the lens of case analysis. There are two possibilities for his results : they either stand up or they don't. Similarly, there are two possiblities for his professional ethics : they are either acceptable, or they aren't. We thus have four possibilities:

  1. He's an honest scientist with legitimate results
  2. He's a dishonest schnook, but with legitimate results
  3. He's an honest but incompetent scientist with invalid results
  4. He's a dishonest weasel with invalid results.
    [/list=1]

    Obviously, if cases 3 or 4 hold, then his findings should not be the basis for public policy. Similarly, if case 1 holds, then his findings should be the basis for public policy.

    But what about case 2? As a scientist, I would like to believe that if his results are valid, public policy should take them into account, even if he's a drug-addicted wife-beater who has defrauded the National Science Foundation out of millions of illegally-obtained dollars. Because no matter what you say about his ethics, if he is correct about the causes and nature of global warming, then it is to be taken seriously.
Click to expand...


  1. I would agree that if his results are legitimate, then his character is irrelevant to whether those results should be taken into serious consideration when framing public policy.

    Einstein was asked about this issue of character over results. When a book was published entitled "100 Authors Against Einstein, he retorted, “If I were wrong, then one would have been enough!".

    It's the same with Mann, Bradley and Hughes. Really.

    I fear, however, that the government is of the opinion that in the event of case 2, they can ignore the legitimate findings by killing the messenger. I further fear that they are planning to find some fault to make sure that Dr. Mann appears to be dishonest regardless of the actual facts of the case. I fear he's being summoned before a kangaroo court that has already determined that he is guilty, and that they are simply searching for the evidence that will show what they already "know" to be the case.
    Click to expand...

    If that were so, then I would be right beside you in condemning such action. But notice the pre-amble to the request (with my emphasis):

    "Questions have been raised, according to a February 14, 2005 article in The Wall Street
    Journal, about the significance of methodological flaws and data errors in your studies of the
    historical record of temperatures and climate change    . We understand that these studies of
    temperature proxy records (tree rings, ice cores, corals, etc.) formed the basis for a new finding in
    the 2001 United Nation’s Intergovernmental Panel on Climate Change (IPCC) Third Assessment
    Report (TAR). This finding – that the increase in 20th century northern hemisphere temperatures is
    “likely to have been the largest of any century during the past 1,000 years” and that the “1990s was
    the warmest decade and 1998 the warmest year” – has since been referenced widely and has become
    a prominent feature of the public debate surrounding climate change policy.

    However, in recent peer-reviewed articles in Science, Geophysical Research Letters, and Energy
    & Environment, researchers question the results of this work    . As these researchers find, based on the
    available information, the conclusions concerning temperature histories – and hence whether
    warming in the 20th century is actually unprecedented – cannot be supported by the Mann et al.
    studies cited in the TAR. In addition, we understand from the February 14 Journal and these other
    reports that researchers have failed to replicate the findings of these studies, in part because of
    problems with the underlying data and the calculations used to reach the conclusions. Questions
    have also been raised concerning the sharing and dissemination of the data and methods used to
    perform the studies    ."
    Click to expand...

    and further

    As you know, sharing data and research results is a basic tenet of open scientific inquiry,
    providing a means to judge the reliability of scientific claims. The ability to replicate a study, as
    the National Research Council has noted, is typically the gold standard by which the reliability of
    claims is judged. Given the questions reported about data access surrounding these studies, we
    also seek to learn whether obligations concerning the sharing of information developed or
    disseminated with federal support have been appropriately met.
    In light of the Committee’s jurisdiction over energy policy and certain environmental issues,
    the Committee must have full and accurate information when considering matters relating to
    climate change policy. We open this review because this dispute surrounding your studies bears
    directly on important questions about the federally funded work upon which climate studies rely
    and the quality and transparency of analyses used to support the IPCC assessment process.    "
    Click to expand...

    It's on those very carefully worded concerns about the probity of the research and the funding program on which it was based, that the Committee has decided to act.

    I don't doubt for one second that the Committee has had expert help when framing some of the very specific questions made in the request referring to statistical validation. But, in this case, the Committee clearly felt that these were legitimate areas of concern.

    This is an issue that won't go away. I'd much rather that the Committee were not involved and that Mann, Bradley and Hughes had ponied up all their code and methodology a long time ago.

    But it does beg the question: If the research is so scientifically sound and robust, why hide how it was done?
 
Diamond said:
All of this is related to why Mann has refused to disclose his methodology if his work . . .

Since Mann has flat out refused to disclose key pieces of work, then the Committee wants to know on what basis he does so. The Hockey Stick is not the only piece of work that Mann refuses to disclose data, code and methodology.
Click to expand...

Umm I didn't really follow this kerfufle closely until these letters came out, but the methodology is described in the paper and the data sets used were expressly stated in a corrigendum in the journal Nature. More specifically, the data and a detailed explaination of the algorithm can be found on the nature website. http://www.nature.com/nature/journal/v430/n6995/extref/nature02478-s1.htm So from what I can find with a brief search, I think it is a gross mischaracterization to claim that the authors are flat out refusing to reveal this.

In addition, a large portion of the information requested by the letters can be found by visiting Mann's website:
http://holocene.evsc.virginia.edu/Mann/index.html
Doesn't the comittee have staff members that can use google?

The real question is: Why is this committee sending partisan sounding and acusatory letters to researchers demanding information based on the disputed claims of one group of researchers? Call me a bit jaded, but, to me, those letters read more like attempts at intimidation then a genuine search for facts.
 
TonyL said:
Umm I didn't really follow this kerfufle closely until these letters came out, but the methodology is described in the paper and the data sets used were expressly stated in a corrigendum in the journal Nature. More specifically, the data and a detailed explaination of the algorithm can be found on the nature website. http://www.nature.com/nature/journal/v430/n6995/extref/nature02478-s1.htm So from what I can find with a brief search, I think it is a gross mischaracterization to claim that the authors are flat out refusing to reveal this.
Click to expand...


Unfortunately, not true. Different groups of researchers have come to the same conclusion: MBH98 is not properly described in either the original paper or the Corrigendum.

See this article by Steve McIntyre on this very point

In addition, a large portion of the information requested by the letters can be found by visiting Mann's website:
http://holocene.evsc.virginia.edu/Mann/index.html
Doesn't the comittee have staff members that can use google?
Click to expand...

They do. But they aren't psychic either.

The real question is: Why is this committee sending partisan sounding and acusatory letters to researchers demanding information based on the disputed claims of one group of researchers? Call me a bit jaded, but, to me, those letters read more like attempts at intimidation then a genuine search for facts.
Click to expand...

If it was one group, then I'd agree with you, but the Committee cited multiple groups and multiple peer-reviewed articles.

I don't see what's particularly partisan about asking the authors of an extremely influential scientific paper to show all their working after not a few independent researchers reported severe methodological problems when attempting to replicate that same study.

Of course, I'd rather the politicians weren't involved at all.

Edit: Steve McIntyre is obviously in a posting frenzy at the moment and has just posted this article on full disclosure in climate science
 
TonyL said:
Umm I didn't really follow this kerfufle closely until these letters came out, but the methodology is described in the paper and the data sets used were expressly stated in a corrigendum in the journal Nature. More specifically, the data and a detailed explaination of the algorithm can be found on the nature website. http://www.nature.com/nature/journal/v430/n6995/extref/nature02478-s1.htm So from what I can find with a brief search, I think it is a gross mischaracterization to claim that the authors are flat out refusing to reveal this.

In addition, a large portion of the information requested by the letters can be found by visiting Mann's website:
http://holocene.evsc.virginia.edu/Mann/index.html
Doesn't the comittee have staff members that can use google?

The real question is: Why is this committee sending partisan sounding and acusatory letters to researchers demanding information based on the disputed claims of one group of researchers? Call me a bit jaded, but, to me, those letters read more like attempts at intimidation then a genuine search for facts.
Click to expand...

You should invest some more time in this issue, it is fascinating.

The essential point is the Mann has not revealed sufficient information, code etc. on his work to allow for the complete replication. Nobody has been able to replicate it, although some have got close (Mcintyre and McItrick for example), but they need to make assumptions about what MBH did and some of the assumptions aobut methodology or data manipulation required to achieve this close replication imply that there are serious flaws in Mann's paper. The most serious of which is that his method (or what is thought to be his method) "mines" times series for a hockey stick shaped pattern, which then will dominate the results. In the date used by Mann there is such a series (tree ring data).

Other researchers can't simply point out the flaws in Mann's work, because they don't have all (in fact the crucial) information.

None of the links you provide give all that information and the corrigendum did not address the points and even made claims that were not peer reviewed (and in fact inserted after draft copies of it had been circulated to relevant parties).

Mann has built a rod for his own back on this. From day one, he has failed and subsequently refused to provide all the information that should be available in order to replicate and validate his own findings and advance research in this area. Maybe it was incompetence initially (lost data and code etc.), but now he is just filibustering.
 
Diamond wrote:
If it was one group, then I'd agree with you, but the Committee cited multiple groups and multiple peer-reviewed articles
Click to expand...

It seems like their are two main groups critical of Mann:
David R. Legates, Dr. Willie Soon, Dr. Sallie Baliunas
Ross McKitrick, Steven McIntyre

Has either of these two groups succeeded in getting an article published in a peer reviewed journal? Are there other groups?
 
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