Where's the fraud?

In previous posts I have discouraged discussion of Michael Mann's work since I had not investigated it at all myself - but inevitably it came up anyway. There were a couple of interesting comments from Steve Mosher and AMac that I am highlighting in this post. If commenters here agree that the Tiljander case is the closest thing anybody has come up with to show consistent misbehavior by climate scientists (following the basic "fraud-like" criteria I set out) then I commit to looking into it myself and trying to understand why scientists and bloggers seem to be disagreeing about it. AMac's denial of "fraud" while calling it an "honest mistake" seems odd to me - if it's really an "honest mistake" it should be acknowledged, not repeated.

Or if folks here think the Tiljander case is not a real problem but some other hockey stick "trick" or feature is definitely fraudulent, I'll look there. Tell me what your best case is!

Just because scientists are human - that is biased, inconsistent, lazy, argumentative, make mistakes, argue, play "politics", etc. etc. does not make some piece of science a fraud. Scientists in their natural state are fiercely competitive with one another - recognition for solving some problem or being first to discover some new truth about the world is all that matters. Tearing down somebody else's work, if you're right, is always grounds for praise. As long as there is some collection of predictions about the world from a piece of science and measurements to verify those predictions, then no matter what the biases or mistakes of the scientists involved, as long as they are not being deliberately fraudulent, the truth will prevail. Of course, without that check and balance from nature, even without fraud, science can get wildly speculative (*cough* string theory *cough*).

Human frailties can mar any piece of scientific work, and this shouldn't surprise anybody. The worry is that some pieces of work that people have come to respect and rely on have been, in some manner, fabricated and are themselves wrong. But fraud is hard to perpetuate in science - it almost always turns up later when others try to do the same experiment or analysis over again and consistently get some different result. On the other hand, if there has not been any actual fraud, what's the problem? The science is still right, even if the scientists behaved abominably (and I've personally witnessed some pretty abominable stuff from people who received great honors...). That's sort of the beauty of the objectivity that the intrinsic competition and reference to nature of science forces on you: personalities really don't matter, only the truth does - it's only the thought that counts as I wrote some time ago.

But - there have been cries of fraud. Let's try to get to the bottom of them. Here are 5 objective criteria for clear continuing fraud that I posted here in a comment the other day:

(1) A result (graph, table, number) presented in a peer-reviewed or IPCC article that was false - i.e. said to be one thing, but was actually something else. Incomplete presentation is not sufficient - I want to see something that was actually false (such as this AR4 case would have been if it had worked out). Truncation doesn't count unless they claimed to be presenting a whole series and clearly actively concealed the truncation. End-point smoothing doesn't count (for example the Briffa 2001/NCDC graph) unless they specified how they were handling the endpoints and did it differently. Etc.

(2) Where the falsity made a material difference to the overall message of the graph, table or number. That is, the visual or mental impact of the difference is obvious to a cursory look at the presentation, and doesn't require detailed magnification of the curve or looking at the last decimal point to see any difference.

(3) Where the problem, identified by blogger or scientist or whoever, has been presented in a clear manner demonstrating the "wrong" and "right" versions for all to see

(4) Where the original scientific group responsible has not responded with acknowledgment of the error and corrected the record as far as possible, and committed not to make the same mistake again

(5) Where the original group has in fact repeated the error more than once, after public disclosure of the problem.

I'm reposting here two lengthy responses to this outline, and encourage further discussion of these in the comments below:

From AMac:

Tiljander/Mann Fraud?

...Short answer: No, But.

This freestanding comment is a Reply to MikeN's "Interesting, I think" (Sun, 6/27/2010 - 00:36) and Arthur Smith's "On the "'my standard' question" (Sat, 06/26/2010 - 18:26). This seeming side-issue may illuminate some of the points being discussed with the termination of the Briffa series in 1960.

Arthur listed 5 criteria in "On the 'my standard' question". Paraphrasing,

(1) A false result is presented in a peer-reviewed article or IPCC report.
(2) The falsity made a material difference to the overall message of a graph, table or number.
(3) The "wrong" and "right" versions of the identified problem have been presented in a clear manner.
(4) The authors have not acknowledged and corrected the error, or committed to not repeat the mistake.
(5) The authors have repeated the error, after public disclosure of the problem.

Two definitions for "Fraud":

a: deceit, trickery; specifically: intentional perversion of truth in order to induce another to part with something of value or to surrender a legal right
b: an act of deceiving or misrepresenting: trick

We're in tricky [sic] territory already: accusers can mean (or claim to mean) that they're discussing "misrepresentation", but the charge of evil intent is present or nearby. Lack of care and precision in statements made by scientists and advocacy bloggers is one of the major polarizing factors the AGW dispute, IMO. Steve covered this ground nicely in Climategate: Not Fraud, But 'Noble Cause Corruption' (also note the cries for blood in the comments).

It's tractable to evaluate what somebody wrote in a journal article, much less so to ascertain what was in their heart at the time of writing. To me, this says most "fraud" charges will be either wrong or unprovable. They'll always be red flags to a bull (bug or feature?).

As described in the Methods and SI of Mann08 (links here), Prof. Mann and co-authors set out to catalog and use non-dendro proxies that contain temperature information. They assembled candidates and looked at behavior over the time of the instrumental record, 1850-1995. During this time of warming, the calculated mean temperature anomaly in most CRUtem cells (5 deg longitude x 5 deg latitude) rose. Proxies with parameters that also rose passed screening and progressed to the validation step (see the paper). The four measures (varve thickness, lightsum, X-Ray Density, and darksum) taken by Mia Tiljander from the lakebed varved sediments of Lake Korttajarvi, Finland also passed validation, and thus were used in the two types of paleotemperature reconstructions (EIV and CPS) that make up the paper's results. The authors recognized potential problems with the Tiljander proxies, but used them anyway. Because of their length (extending much earlier than 200 AD) and the strength of their "blade" signal (Willis Eschenbach essay), the proxies are important parts of the reconstructions.

The evidence is overwhelming that Prof. Mann and co-authors were mistaken in their belief that the Tiljander proxies could be calibrated to CRUtem temperature anomaly series, 1850-1995. The XRD proxy discussed here. The issue was recently raised again by A-List climate scientist and RealClimate.org blogger at Collide-a-Scape, The Main Hindrance to Dialogue (and Detente). Gavin and Prof. Mann's other allies are unable to address the matters of substance that underlie this controversy; see my comment #132 in that thread.

Arthur's 5 Criteria and Mann08/Tiljander
(0) Mann08's use of the Tiljander proxies is not fraud, IMO. All evidence points to an honest mistake.

(1) False result presented in a peer-reviewed article? Yes.

(2) Falsity made a material difference to the overall message of [graphs]? Hotly contested. Mann08 has many added methodological problems, making it difficult to know (see comment #132 and critical posts linked here). IMO, this demonstrated failure of key Mann08 methods (screening and validation) calls the entire paper into question.

(3) Clear presentations of "wrong" and "right" versions of the identified problem? Hotly contested. Gavin believes that the twice-corrected, non-peer-reviewed Fig S8a shows that errors with Tiljander (if any) don't matter. I rebut that in comment #132 and in this essay.

(4) The authors have not acknowledged and corrected the error, or committed to not repeat the mistake. Yes. In their Reply published in PNAS in 2009, Mann et al. called the claims of improper use of the Tiljander proxies "bizarre."

(5) The authors have repeated the error, after public disclosure of the problem. Yes. Mann et al. (Science, 2009) again employed the Tiljander proxies Lightsum and XRD in their inverted orientations (ClimateAudit post); see lines 1063 and 1065 in "1209proxynames.xls" downloadable in zipped form from sciencemag.org (behind paywall).

Summary, and Lessons for the Briffa Series Truncations
The key issue is not fraud. Nor is it that authors of peer-reviewed articles make mistakes. Everybody--scientists, book authors, and climate-bloggers included--makes mistakes.

Instead, the important question is: Does climate science adhere to Best Practices? Appropriately, scientists and bloggers scrutinize articles that cast doubt on the Consensus view of AGW, as shown by Tim Lambert in the 2004 radians-not-degrees case. What about papers that support the Consensus view? Are such errors in those papers picked up? Do the authors correct those papers, too?

Best Practices don't mainly concern the detection of glaring, easily-understood errors like a radian/degree mixup or an upside-down proxy. There are a host of issues -- as there are with drug research, structural engineering, mission-critical software validation, and a large number of other areas. I won't enumerate them -- beyond a plea for the correct and rigorous use of statistical tools. Recent threads at Collide-a-scape are full of suggestions and insights on this question, from AGW Consensus advocate scientist Judith Curry, and many others.

The key to the Tiljander case is the defective response of the scientific establishment and the AGW-advocacy-blogging community. I think it teaches that paleoclimatology is a young science that has yet to establish Best Practices (as the concept is understood by other specialties, by regulators, or by the scientifically-literate lay public). To the extent that Best Practices should be obvious -- e.g. prompt acknowledgement and correction of glaring errors -- scientists' and institutions' responses merit a "D" or an "F" to this point.

Broadly speaking, I think scientifically-literate Lukewarmers and skeptics accept the analysis of the last few paragraphs. In contrast, opinion-setters in the climate science community and among AGW-Consensus-advocacy bloggers emphatically reject it.

IMO, these differing perceptions explain much of the gulf between the opening positions of Steve Mosher and Arthur Smith on the general question of the justification for the 1960 truncation(s) of the Briffa series, and on the specific question of Steve's error in ascribing the padding of the AR4 truncation to a splice with the instrumental record.

From Steve Mosher

I think this is a really important comment. It lets me describe the central thesis of the book and our view of things.

What the mails detail is the creation of a bunker mentality. this mentality is best illustrated by some of the mails written by Mann. Essentially it is a vision of a battle between climate scientists and skeptics. Us and them. I put aside the question of whether this
mentality was justified or not. The important thing is that this mentality existed. Jones in an interview after climategate confirms the existence of this mentality. I do not think there is any evidence that contradicts this observation. The mentality existed. It is reflected in the language and the actions. What I try to focus on is how this mentality shapes or informs certain behaviors. We struggled a great deal with the language to describe the behavoir. Fraud was too strong a description. I would say and did say that the mentality eroded scientific ethics and scientific practices. it lead to behaviors that do not represent "best practices." These behaviors should not be encouraged or excused. They should be fixed.

When we try to make this case we face two challenges. We face a challenge from those who want to scream fraud and we face a challenge from those who want to defend every action these individuals took. Finding that middle road between "they are frauds" and "they did no wrong." was difficult to say the least. In the end its that middle ground that we want claim. The mails do not change the science ( said that many times in the book), but the behaviors we see are not the best practices. We deserve better science, especially with the stakes involved. If our only standard is the standard you propose, then I don't think we get the best science. I'll just list the areas in which I think the bunker mentality lead people to do things they would not ordinarily do. And things we would not ordinarily excuse.

A. Journals. There are a a few examples where the mails show the small group engaging in behaviors or contemplating behaviors that dont represent best practices.

1. Suggesting that "files" should be kept on journal editors that make editorial decisions you dont agree with
2. Influencing reviewers of papers.
3. Inventing a new category ( "provisionally accepted") for one paper so that it can be used by the IPCC.

B. Data archiving and access.
1. Sharing data that is confidential with some researchers while not sharing it with others. If its confidential, its confidential. If its
not, then its not.
2. Failing to archive data.

C. Code sharing.

1. Withholding code when you know that the code differs from the method described in the paper and correspondents
cannot replicate your results because of this discrepency. And you know they cannot replicate BECAUSE of this failure
of the paper to describe the code completely.

D. Administrative failures.
1. Failure to discharge one's administrative duties. see FOIA.

E. Failure to faithfully describe the total uncertainties in an analysis.

As you can see, and as we argue, none of these touches the core science. What we do argue is this. The practices we can
see in the mails do not constitute the best practices. I've argued at conservative sites that this behavior did not rise to the
level of fraud. And I took my lumps for failing to overcharge the case. On the other hand, those who believe in AGW (as we do), are unwilling to acknowledge any failings. We were heartened by Judith Curries call for a better science moving forward. We think
that the behaviors exhibited do not represent the best science. We think we can and should do better. The gravity of the issue demands it. So on one side we hear the charges of fraud . That's extreme. On the other side we hear a mis direction from the core issue. When we point out that best practices would require code and data sharing,for example, the answer is
" the science is sound." we dont disagree. What we say is that the best path forward is transparency and openness. Acknowledge that the decisions made were not the best and pledge to change things going forward.

Concern E is the heart of the matter WRT chap 6 of WG1. On our view Briffa was put under pressure to overstate the case.
That's not fraud. It's not perpetuating false statements. If you study the mails WRT to the authoring of that chapter you will come away with the impression that Briffa was under pressure to overstate the certainty. That doesnt make AGW false. It cannot. It is however a worrisome situation.

Here is Rind advising the writing team.
"pp. 8-18: The biggest problem with what appears here is in the handling of the greater
variability found in some reconstructions, and the whole discussion of the 'hockey stick'.
The tone is defensive, and worse, it both minimizes and avoids the problems. We should
clearly say (e.g., page 12 middle paragraph) that there are substantial uncertainties that
remain concerning the degree of variability - warming prior to 12K BP, and cooling during
the LIA, due primarily to the use of paleo-indicators of uncertain applicability, and the
lack of global (especially tropical) data. Attempting to avoid such statements will just
cause more problems.
In addition, some of the comments are probably wrong - the warm-season bias (p.12) should
if anything produce less variability, since warm seasons (at least in GCMs) feature smaller
climate changes than cold seasons. The discussion of uncertainties in tree ring
reconstructions should be direct, not referred to other references - it's important for
this document. How the long-term growth is factored in/out should be mentioned as a prime
problem. The lack of tropical data - a few corals prior to 1700 - has got to be discussed.
The primary criticism of McIntyre and McKitrick, which has gotten a lot of play on the
Internet, is that Mann et al. transformed each tree ring prior to calculating PCs by
subtracting the 1902-1980 mean, rather than using the length of the full time series (e.g.,
1400-1980), as is generally done. M&M claim that when they used that procedure with a red
noise spectrum, it always resulted in a 'hockey stick'. Is this true? If so, it constitutes
a devastating criticism of the approach; if not, it should be refuted. While IPCC cannot be
expected to respond to every criticism a priori, this one has gotten such publicity it
would be foolhardy to avoid it.
In addition, there are other valid criticisms to the PC approach....."

The PARTICULARS of this are unimportant. What matters is Rind's advice about treating uncertainties in a forthright manner.
All of our criticism of Briffa can be summed up in one sentence. He didn't do the most forthright description of the uncertainties.
That's it. whether it was his treatment of McIntyre's paper, or failing to disclose the truncated data in the clearest manner, that is the take home point we want to stress.

However, I'm not sure I understand why Steve is reluctant to cry "fraud" - or AMac for that matter. As I noted at the start, if "Tiljander" (whatever that means, I have not looked into it at all myself) makes a difference and they're still doing it wrong without acknowledging the error, then either perhaps the error hasn't been explained in a clear enough manner (showing how it makes any difference), or that's real fraud. Same with Steve Mosher's complaint about what Briffa was "forced" into (whether or not the emails provide enough context for these conclusions I can't say either - again I haven't looked into it myself). But if what Steve says here is true, then there was a numerical quantitative parameter - uncertainty - that was mis-stated in the IPCC reports. A proper analysis would show a different number. If Steve is right somebody should be able to do that proper analysis and get the right number, and show how it makes a difference. Persistence in using the wrong number after it's been shown there's a correct one would again be an instance of continued repeated fraud.

So - is it there, or not? What's the best case? Comments welcome on Mann in particular here, thanks!


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A response to "Why do you

A response to "Why do you think I would know," Arthur Smith, Mon, 06/28/2010 - 14:33

Arthur, you wrote,

The best option would be Steve's #2 suggestion - [for Tiljander et al to] publish both the full series (with caveat: *do not use this for reconstructions unless you know what you're doing*) and a truncated series ("suitable for use in reconstructions").

In the March 2010 post I recommended to your attention earlier, I quoted from Tiljander et al (Boreas, 2003). Here are two passages, the first from page 572:

In the case of Lake Korttajarvi it is a demanding task to calibrate the physical varve data we have collected against meteorological data, because human impacts have distorted the natural signal to varying extents during the past 280 years and the meteorological data in the Jyvaskyla area are only available since 1881.

And page 575:

In the 20th century the Lake Korttajarvi record was strongly affected by human activities. The average varve thickness is 1.2 mm from AD 1900 to 1929, 1.9 mm from AD 1930 to 1962 and 3.5 mm from AD 1963 to 1985. There are two exceptionally thick clay-silt layers caused by man. The thick layer of AD 1930 resulted from peat ditching and forest clearance (information from a local farmer in 1999) and the thick layer of AD 1967 originated due to the rebuilding of the bridge in the vicinity of the lake's southern corner (information from the Finnish Road Administration). Varves since AD 1963 towards the present time thicken because of the higher water content in the top of the sediment column. However, the gradually increasing varve thickness during the whole 20th century probably originates from the accelerating agricultural use of the area around the lake.

Subtracting 280 years from the publication date could be interpreted as a "Proceed With Caution" warning for the period 1723-forward.

Would you agree?

Certainly could be

Certainly could be interpreted that way, that makes sense to me. But if Tiljander et al had done so explicitly with their published series there wouldn't be any need for such interpretation, would there?

Arthur, you wrote (Mon,

Arthur, you wrote (Mon, 06/28/2010 - 17:10)

But if Tiljander et al had done so explicitly with their published series there wouldn't be any need for such interpretation, would there?

Er... Re-read those excerpts. How much more explicit than "280 years" should they have gotten? The Mann08 authors quoted Tiljander (2003), so it's fair to assume they read it, yes?

No, The proper method is to


The proper method is to do what GHCN and others do with raw data. They publish the data with QUALITY flags for the data.
This way the whole chain of custody is preserved and all of the decisions are documented. That is just standard practice where I come from. You NEVER delete raw data. You archive raw data, even the paper copies it is derived from if need be. Then as you press that data through QC you document and provide the QC program and the intermediate steps. This is just basic good engineering. Even GHCN does it wrong in places, especially with preserving the records ( they call them duplicate records).. in the case of duplicate records, for example, the expurge records that are 90% similar ( records from the same location). For full tracibility its important to maintain the entire record.

Now, I'm willing to say ( having worked with scientists on these types of problems before) that they lack the training to keep a proper archive and proper records. That's not fraud. That's just lack of awareness. But, having been made aware of the shortcomings, I think they should ammend their methods. rather than argue that they didnt commit fraud, just commit to improved methods. It really is the pinnacle of silliness, to try to defend sub standard practice because it hasnt lead to a fraud, yet. It speaks volumes to the communities commitment to the best science for this troubling issue we face. It says that you care more about the answer you want, than maintaining a good process. Judith Curry gets this. She can't be the only one.

Steve, who deleted raw data?

Steve, who deleted raw data? Be specific in your accusations, this stuff is really way too vague.

Tracking provenance is tricky - I agree it's important, but given the many different forms "data" can take, handling the meta-data properly is not a trivial matter. Especially when you're doing frontier work, every bit of data tends to be in a completely non-standard form for which there are few or no existing simple software tools etc. It's an added burden. Yes, it would be better to track completely, especially with modern IT capabilities.

If there are *specific* suggestions for improvement that have been made but have been ignored then we can discuss those too. But I see it as a much less significant issue than claims of actual wrongness not corrected and indeed persisted in. Tiljander sounds like such a case - do you agree, or not?

The paleoclimate studies

The paleoclimate studies shouldn't just be playing with data, but actually having knowledge of what you are doing. For this study, it makes less sense given what they were doing in the paper. It was not a climate reconstruction, but evaluating all factors. They call it a palaeoenvironmental study in the title. But yea, no archiving would eliminate the problem.

I just find it really hard to

I just find it really hard to make an accusation of fraud in this case. The impacts on the recon were explored in the SI and found to be minimal wrt to the overall results. The reason for the inclusion was discussed in the SI. This hardly amounts to fraud. You might disagree with the judgment call made in this case, but FRAUD, surely you jest.

I'm trying to ferret out the

I'm trying to ferret out the best case our skeptic friends have - "Tiljander" seems to be what everybody has settled on, but maybe there's something better.

Because if there's no fraud, then what's all the fuss about? People being sloppy? Even though it makes absolutely no difference to the results? Really?

Response to Rattus

Response to Rattus Norvegicus, (Mon, 06/28/2010 - 21:50)

> The impacts on the recon were ... found to be minimal wrt to the overall results.

Does "found to be minimal" refer to comparing reconstruction traces in the twice-revised, non-peer-reviewed version of Fig. S8a? Do you think there is any additional evidence that can be brought to bear on the effect of the Tiljander proxies on the results?

> but FRAUD, surely you jest.

Could you specifiy who is making the allegation you are referring to?

> The impacts on the recon

> The impacts on the recon were ... found to be minimal wrt to the overall results.

Found to be minimal in the SI of the paper. I believe ClimateAudit found differently, and will run some numbers to see what happens.
The issue is that you take out these and find no problems. Plus you run sensitivity tests for other proxies. However, if you take out Tiljander, then the other robustness sensitivity tests can be affected. If you have two problem proxies that create hockey sticks, then leaving out just one at a time, still gives you a hockey stick.

Arthur, it is extremely hard

Arthur, it is extremely hard to follow arguments from comment to comment. It's also hard to zero in on the newest contributions. Maybe it's just me, but this is my experience with this blog, both for a Mac running Firefox or Safari, and for a Dell running Firefox and IE7.

In a way that's too bad; in another way it is perhaps fitting.

There's definitely some bits

There's definitely some bits of the blog not working quite right yet - I've only had one or two pieces in the past with this many comments, so it hadn't seemed like such a problem!

But if you register for an account I think you may find things working better. The first time you click to the page, for instance, new comments should be flagged as "New". Also your posts will appear immediately rather than waiting for moderation (assuming you behave).

Also, what do you have set for your "Comment Viewing Options" up top? I find "Threaded" and 200 per page works...

So this is how it looks to

So this is how it looks to me. The fans of Mann08 (Arthur and most commenters) basically agree with Martin Vermeer, in his answers to my two questions.

Question 1 is, "Are the four Tiljander proxies calibratable to the instrumental temperature record, 1850-1995?"

And Martin's answer was

Perhaps, perhaps not. I don't know. but it doesn't matter (much). And that I do know.

Question 2 is, "Is it acceptable scientific practice for Mann08’s Methods section to be silent on these highly unconventional uses of the Tiljander proxies?"

And Martin's answer was,

Yes, sure they could have commented on this... OTOH these are interpretations and inherently uncertain. If the Mann interpretation is wrong, we arrive again at the alternative that the proxies are unusable. Which is considered in the paper. So, no big issue.

The approach that Prof. Mann's group used was to devise a screening and validation protocol in order to calibrate proxies to the instrumental record. To answer "perhaps, perhaps not" to Question 1 is to say that one cannot have confidence that Mann and co-authors did as they intended, for the four Tiljander proxies.

Of course, that still leaves 11 other long-range Northern Hemisphere proxies that they did succeed in calibrating. And 1205 other proxies still calibrated, in total.

Hence the follow-up question, for Martin, Arthur, Rattus, others. What number of uncalibratable proxies would be "too many"? In other words, what number would cause you to say that (1) the authors should correct the Methods to note the sometimes-failure of the screening-verification-calibration procedure, and (2) the Results would have to be given less credence due to flaws in the science.

It seems to me that "no more than half" can be used to set a reasonable boundary case. I would expect the benefits of 605 correctly-calibrated proxies to outweigh any problems with 604 uncalibrated ones. However, if it turned out that a majority of proxies (i.e. 605) couldn't be calibrated, that would pose some difficulties.

The second follow-up question is easier. Could you specify the figures, tables, or text which teach that the use of the uncalibratable (and in the cases of lightsum and XRD, inverted-orientation) Tiljander proxes "doesn't matter"? Twice-revised Figure 8a has come up in this thread on this issue. Is there any other evidence to consider?

AMac, as to your first


as to your first question, I am not sure I understand you. By an 'uncalibratable' proxy, do you mean one where there is some unknown effect or contamination in the calibration period? That is precisely the kind of thing the various sensitivity studies are meant to guard against. And 50% is huge. If 50% of the dendro proxies, e.g., were thus uncalibratable, we would surely see a large difference between the full-solution curve and the one with tree rings removed. The same if 50% of the non-tree ring proxies were so affected. This is why one does these tests in the first place.

So I think the percentage is much smaller -- except possibly for the very early years where this cannot be ruled out.

Reply to Martin Vermeer,

Reply to Martin Vermeer, "AMac, as to your first" Tue, 06/29/2010 - 04:29

> By an 'uncalibratable' proxy, do you mean one where there is some unknown effect or contamination in the calibration period?

Yes, though you may strike the word "unknown." In the case of the Tiljander proxies, the contamination was identified in the 2003 Boreas paper. To review, I quoted that text yesterday, in this thread.

> That is precisely the kind of thing the various sensitivity studies are meant to guard against.

I agree, that is the intention, and it's admirable. That is not to say that such studies are always effective. In the present instance, the twice-revised twice-corrected Fig S8a has been offered as such a sensitivity study. My second follow-up was meant to get at whether you and others interpret other figures, tables, or text as weighing in on this question. Any thoughts?

> And 50% is huge. If 50% of the dendro proxies, e.g., were thus uncalibratable...

OK, if 50% is too huge, what number isn't? 4 of the 15 Northern Hemisphere proxy records that pass the screening procedure back to at least AD 818 (Fig. S9 legend) is 27%; 4 of 1209 is 0.3%. I'm asking, not trying to paint you, Arthur, Rattus, et al. into a corner. Perhaps your meaning is that any percentage of uncalibratable proxies is OK, as long as the with/without reconstruction traces pass a sensitivity test such as depicted in Fig S8a?

Yes, your last sentence sums

Yes, your last sentence sums it up as I see it. Note that it isn't just a question of which percentage of proxies is contaminated, but also the size of the contamination.

This is just a special example of using redundancy in the data itself to find and eliminate gross or systematic errors. Like in a geodetic network where you form triangles and verify that the sum of angles in each is 180 degrees. Big gross errors will be caught; small ones will slip through but will be harmless, being small.

Sensitivity tests -- Response

Sensitivity tests -- Response to "Yes, your last sentence sums" Tue, 06/29/2010 - 11:52


We've identified Fig. S8a as a sensitivity test. Are there any other parts of the paper or SI (figures, tables, text) that also contribute to sensitivity testing, or does Fig. S8a stand alone in that regard?

Should a sensitivity test have a numerical component, or does it suffice (in practical terms) to use a qualitative approach, e.g. inspecting the traces in Fig. S8a and seeing that they represent sufficiently similar reconstructions? Should a sensitivity test have a statistical output, e.g. a P value associated with a certain threshold of change?

Arthur, Rattus, others -- your thoughts?

BTW, Ari Jokimäki has a new

BTW, Ari Jokimäki has a new post up, Tiljander, on his blog AGW Observer. He inspired me to post some data I compiled a while back, the CRUtemv3 temperature anomaly record 1850-1996 for the 5 degree by 5 degree "gridcell" that covers Lake Korttajarvi. According to the Mann08 methods, that is the temperature record that was used to calibrate the Tiljander proxies. My post is here (it's a placeholder; I'm rushed today).

Side note: Arthur, you were right. The comments thread presentation is greatly improved by creating an account here and logging in. I recommend it for regulars.

AMac, good stuff. Jokimäki

AMac, good stuff. Jokimäki describes the situation with "upside down" accurately: it is upside-down relative to Tiljander et al's interpretation, not upside-down as such in the input phase.

Jokimäki is a bit harsh on McIntyre. It seems to me that in his comment he was guilty of imprecision, verbal sloppiness (as so often, sigh), but no actual dishonesty. Anyway, clearly he and Mann were talking past each other.

BTW I skimmed Mia T's thesis a long time ago and seem to remember that these X-ray densities are actually proxies not for temperature but for spring time snow melt run-off. Don't take my word on this.

Martin, My interpretation of


My interpretation of the word "upside-down" as regards Mann08's use of the Tiljander proxies is Comment 8 at Ari Jokimäki's post. I won't repost it here, as it is lengthy and pedantic (so as to be as clear as possible on this never-goes-away semantic issue).

Tiljander03 says "High X-ray density corresponds to high amount of mineral matter (light grey value tints in X-ray film) and low X-ray density corresponds to dark grey values caused by a higher proportion of organic matter." (Fig. 5 legend, page 570). The Figure 9 legend (page 573) states, "LS (light sum) is the sum of grey values and describes the amount of mineral matter. DS (dark sum) = LSmax - LS and describes the amount of organic matter."

Page 571: "The above-mentioned factors, the amounts of inorganic and organic matter, form the basis of the climate interpretations. Periods rich in organic matter indicate favourable climate conditions, when less snow accumulates in winter by diminished precipitation and/or increased thawing, causing weaker spring flow and formation of a thin mineral layer. In addition, a long growing season thickens the organic matter. More severe climate conditions occur with higher winter precipitation, a longer cold period and rapid melting at spring, shown as thicker mineral matter within a varve."

By the way, Finnish scientist

By the way, Finnish scientist Atte Korhola has accused Mann of fraud or something similar(comments were in Finnish). The use of Tiljander was a slamdunk case of fraud in his opinion. This was with Kaufman et al, which issued a correction. I think in Mann's case, he reached the conclusion with regards to a directory on Mann's website that had some unpublished sensitivity calculations.

Yeah, I know Korhola, sigh.

Yeah, I know Korhola, sigh. The Finnish Pielke. He was also in a Finnish TV "documentary" on Climategate, happily misrepresenting the Soon-Baliunas affair.

Anyway thanks for warning me. And for spoiling my day :-(

AMac, having done some

AMac, having done some thinking on the Jokimäki post, I feel I must revisit your earlier second question:

"Is it acceptable scientific practice for Mann08’s Methods section to be silent on these highly unconventional uses of the Tiljander proxies?"

My answer: the question doesn't come up, as Mann et al. weren't aware that this is what they were doing. They simply missed it.

It is easy to miss: you have to realize that the issue exists and go do the comparison. Kaufmann missed it too (to his embarrassment).

There is the "screening" test done to ensure that a proxy is only used if it has some minimal correlation with instrumental temps over the calibration period. It is normally two-sided; one-sided only if there is an a priori physical reason to expect a certain orientation. E.g., a glacier will shorten when it gets warmer, lengthen when it gets colder.You know all this. Mann et al. did not assume such a prior orientation for lake sediment proxies. Had they used the Tiljander interpretation as a prior orientation for a one-sided test, the 'upside down' proxies would have been thrown out at this stage. Would that have been a proper policy choice? You tell me...

Then came McIntyre's botched comment, Feb. 2009. Literally taken it was indeed 'bizarre'. And after it, Mann et al. still weren't aware of the real issue, and managed to publish one more paper before Kaufmann saw the light. A comedy of errors.

This is a reply to "AMac,

This is a reply to "AMac, having done some" by Martin Vermeer (Tue, 06/29/2010 - 16:11)

That is a helpful comment, Martin. In general, my analysis of this point is in agreement with yours. Here, again, is my question referring to Mann08's interpretation of XRD and lightsum -

Is it acceptable scientific practice for Mann08’s Methods section to be silent on these highly unconventional uses of the Tiljander proxies?

I believe that the correct answer is that Prof. Mann and his co-authors unwittingly performed faux calibrations of darksum, lightsum, XRD, and thickness to the instrumental record. Although they quoted Tiljander03's cautionary text on the problem of post-1720 contamination, they did not exhibit sufficient due diligence on this issue. Thus, as they went on with their reconstruction work and prepared their PNAS manuscript, they weren't aware of what they had done. They simply missed it.

To you, with your present insight, my question #2 thus apparently seems strange.

Recall, however, the range of explanations that champions of Mann08 have offered on this point. Prominent among them have been,

* "Prof. Mann and co-authors used the Tiljander proxies in a way that is consistent with Tiljander03."
* "Prof. Mann and co-authors correctly calibrated the Tiljander proxies."
* "Proxies can be used in either orientation; there is no 'right' or 'wrong' to it."
* "Prof. Mann and co-authors need not follow Tiljander's interpretation."
* "Prof. Mann and co-authors took the alleged recent contamination into account."

For the most part, these defenses imply that Mann08's authors knowingly used the Tiljander proxies as they did, including the special cases of lightsum and XRD. So, in discussing the merits of these defenses, my question #2 is a valid point to raise, I think.

Prof. Mann's critics discovered "Upside-Down Tiljander" within a few days of online publication. In the current polarized environment, "tribes" lined up predictably. Scientifically-literate "Skeptics" easily accepted Prof. Mann's error; it fit into their perspective. Scientifically-literate adherents to the AGW Consensus failed to see the error, or refused to admit to seeing it. They lined up to defend "one of their own." This counterproductive behavior continues to this day, e.g. Gavin Schmidt at C-a-s, The Main Hindrance to Dialogue (and Detente).

Mann08's authors aren't stupid, and they read blogs. Within a short period of time, most of them were likely cognizant of the mistake. Yet as you point out, Kaufman et al (Science, 2009) initially made the same error. But Kaufman was able to promptly correct his. Likely, I suspect, because he wasn't as caught up with the politics and/or pride of the situation.

"Which movie deserved the Best Picture Oscar, 'The Hurt Locker' or 'Avatar'?" This question can be debated up to Closing Time, and beyond.

It's a mistake to view "Are the Tiljander proxies calibratible to the instrumental record?" in the same light.

The correct answer to the calibration question is, "No, they are not".

By the time Mann republished

By the time Mann republished in Science in 2009, Steve McIntyre had already published his comment in PNAS, and Kaufman had published his paper in Science, AND Kaufman issued a correction.

Kaufman et al and Mann et al 09 share 2 coauthors Bradley and Ammann.

Hmm. So, Kaufmann was stupid?

Hmm. So, Kaufmann was stupid? Or Kaufmann, contrary to Mann et al., didn't read blogs? And Kaufmann et al and Mann et al weren't on talking terms?

I don't buy it. Yes, they read blogs, but there's one blog in particular they don't read and specifically don't bother to spend time decoding. I stick to my theory.

The reason Tiljander is a "good" example for discussing Mann et al. and scientific dishonesty is not that it is a good example. It is that it is scientifically suitably non-trivial (if it were trivial, McIntyre as a smart guy would have no problem explaining it clearly, right?). This is "useful" in an environment where bad faith is routinely assumed, esp. of prof. Mann (as you do, or at least stubbornness). Yes, the atmosphere for discussion is poisoned, and that works both ways. Should I, seeing how the auditors keep relentlessly hammering on a debatable point of no consequence to the science, also assume that the intent is not to move the science forward but rather to seed doubt about the science? Because that is what it looks like to me.

About your answer to the question "are these proxies calibratable", you may well be right. Or then, you may not. It matters little.

Reply to "Hmm. So, Kaufmann

Reply to "Hmm. So, Kaufmann was stupid?" by Martin Vermeer - Wed, 06/30/2010 - 06:01

> Hmm. So, Kaufmann was stupid?

Earlier today at Ari's, I wrote

I don’t see any evidence in support of the idea that, as a group, skeptics (or skeptics & lukewarmers) are smarter than advocates of the AGW Consensus.

I rule out stupidity as an explanation.

For the question,

"Are the Tiljander proxies calibratable to the instrumental record?"

I've paraphrased Gavin's and toto's answer (at C-a-s) as,

"I don't know, and it doesn't matter."

That seems like a fair paraphrase of your (Martin Vermeer's) response, too ("you may well be right. Or then, you may not. It matters little.")

"I don't know" could mean one of a few related things.

1. "I don't know--I haven't investigated the issue."
2. "I don't know--having looked into it, I haven't come to a conclusion yet."
3. "I don't know--I've looked into it, but I lack the interest/expertise/time/etc. needed to draw a conclusion."
4. "I don't know--it's not one of those questions that I or anyone else can answer definitively."

In discussions, getting to the appropriate level of specificity can be helpful. So perhaps I should follow up with Gavin, toto, you, and others by asking, "When you say 'I don't know,' do you mean #1, #2, #3, #4, or something else?"

You expressed your theory in the "AMac, having done some" comment.

the question [of Mann08's silence on their unconventional interpretation of lightsum and XRD] doesn't come up, as Mann et al. weren't aware that this is what they were doing. They simply missed it.

It is easy to miss: you have to realize that the issue exists and go do the comparison. Kaufmann missed it too (to his embarrassment).


And after it [McIntyre's Feb. 2009 Comment], Mann et al. still weren't aware of the real issue, and managed to publish one more paper before Kaufmann saw the light.

It's unclear to me how this interpretation is consistent with a response of "I don't know" on the question of whether the Tiljander proxies are calibratible.

My answer would be closest to

My answer would be closest to #4, but with the caveat that this is not based on personal expertise on the subject, rather on reading what the experts write.


It's unclear to me how this interpretation is consistent with a response of "I don't know" on the question of whether the Tiljander proxies are calibratible.

It refers to the awareness of the contradiction between the Tiljander interpretation and the (implicit) Mann interpretation. If Mann et al had been aware at the time of writing of their paper, I would expect them to at least acknowledge it in their paper. Had they been aware at the time of the comment, I reckon their response would also have been quite different and, again, would have acknowledged and addressed the issue (in whatever way) instead of just discounting McI as 'bizarre'.

Kaufman became aware of the issue and went as far as accepting the Tiljander understanding -- which is plausible. But the important thing is he acknowledged the issue. What I mean by "seeing the light".

Is this clearer?

Kaufman, upon being made

Kaufman, upon being made aware of the PNAS comment, thru personal communication with Steve McIntyre, issued a correction. The authors of Mann et al did not take much care after seeing McIntyre's comment, or read his blogs, we are supposed to believe. Even after seeing Kaufman's correction, you would think they would take some care. There is evidence of changing source code from Mann in response to reviews at CimateAudit, so it's not like he completely ignores them.

Re: MikeN's "Kaufman, upon

Re: MikeN's "Kaufman, upon being made"

In Comment #5 of the Tiljander-related thread at C-a-s, Gavin Schmidt implies that Mann08's authors revised Fig. S8a in order to address criticisms concerning the use of the Tiljander proxies in Mann08.

Given the methodology used in that particular paper (Mann et al, 2008) (weighting based on a local calibration to temperature in the modern period), the 'tiljander' proxies can only be used one way. If there is a contamination in the modern period by non-climatic influences (which the originating authors suggested there might be), then they just can't be used. This issue was clearly acknowledged in the M08 paper and both of these possibilities (with and without 'tiljander') were shown (it made almost no difference to the final reconstruction).

Supp. Fig. S8a

(Note that figure also shows the difference dropping all the tree-ring data makes, and what happens when the neither the tree ring data nor the Tiljander proxies are not used).

(Note that the final sentence of Gavin's comment is only applicable to the third version of Fig. S8a, uploaded to Prof. Mann's Penn State website in early November 2009 . This caused some confusion among people who referred to the Fig. S8a that was in the original SI, and is still archived at the Mann08 page at PNAS.org.)

To my knowledge, the claim that Mann08's use of the Tiljander proxies "doesn't matter" is entirely based on interpreting the paleotemperature reconstruction traces in this twice-revised, non-peer-reviewed version of Fig. S8a.

To my knowledge, the claim

To my knowledge, the claim that Mann08's use of the Tiljander proxies "doesn't matter" is entirely based on interpreting the paleotemperature reconstruction traces in this twice-revised, non-peer-reviewed version of Fig. S8a.

Eh, the comparison is already done in the original, peer reviewed version of S8a in the paper. Yes, it was twice revised after that, but doesn't look very different to me from the original.

The main, unrelated change is the addition of the "both dodgy proxies and all tree rings removed" curve. It is a living demonstration of denialism in action: the usual suspects, seeing that neither dropping the "dodgy proxies" nor dropping all tree rings made the thing break down, of course wanted to grasp at straws and demanded "but what if you drop both?"

Well, the buzz trickled through to Mike Mann -- sometimes it does -- and nice guy that he is, produced a bonus curve, courtesy of Penn State... looking of course completely predictable. [Yawns, and suppresses sarcastic remark.]

Martin Vermeer, thinking

Martin Vermeer, thinking about your comment "To my knowledge, the claim" and the #18 at AGW Observer by James Lane has brought up a new idea for approaching the questions raised in Arthur's post. 50/50 chance that it pans out; it'll take a while to find out. I hope so.

I rarely get to say, "Thanks for the insult," but it applies here. Cheers, AMac

Martin, somehow I'd missed

Martin, somehow I'd missed that Mann had conducted the sensitivity study I was planning on doing, and to which I'd referred above, as to whether Tiljander violates Arthur's criteria 2.

Looking at Mann's result, which seems to be in agreement with McIntyre's, the results do matter.
The whole point of various hockey stick studies is to say temperature is unprecedented, warmer than Medieval times, and this is one more reason to believe that CO2 is the reason for the warming.
I think that last point is irrelevant, but it is at least part of the argument.
It's not the existence of rising temperatures that is at issue, but the differential with past climates.

Mann's updated version without dendro and Tiljander places that conclusion in doubt, and the results are substantially different than all proxy case. Note that the dendro proxies are an issue, specifically with regards to bristlecone pines. This was also mentioned in McIntyre's comment, that the NAS Panel concluded bristlecones/foxtails/strip-bark should not be used. Mann responded that their is new work making them usable.

McIntyre concluded that the no-bristlecone, no-Tiljander case is similar to the no-tree-rings-no Tiljander case. The bristlecones were responsible for most of the hockey stick.

I find this result surprising given 1200 proxies, and the algorithm being used. I would think that 1200 random proxies that are sent through a filter of matching to the temperature record should produce a hockey stick.

MikeN, for a different sort

MikeN, for a different sort of sensitivity study, see this Nov. 23, 2008 ClimateAudit post by Willis Eschenbach, Can't See the Signal For the Trees. Figure 10 presents his conclusion. Note the prominent contributions of the Tiljander proxies and bristlecones, by this method.

(I disagree with many of Eschenbach's conclusions on the instrumental record, e.g. where they don't accord with work by Zeke Hausfather and others. Based on credible reports, I object to the comments policy of the blog WUWT, where he often posts. That said, this and other paleotemperature contributions by Eschenbach seem excellent, to me.)

MikeN, the Kaufman situation

MikeN, the Kaufman situation differed essentially from the Mann et al. one. The former hadn't even considered the Tiljander et al. authors' caution on possible contamination, and happily used the whole record in 'Mannian' orientation, without apparently even being aware of it. This called very much for a correction. Contrast this with what Mann et al. did: covering all their bases as it were by doing the computation both with and without these proxies, and comparing. As also Gavin Schmidt asserts (see below quotation in AMac's comment), this addresses the issue.

The only real mistake in Mann et al. remaining is then not mentioning (and apparently initially not noticing) the conflict in orientation with Tiljander's. A small thing, not affecting conclusions, and certainly nothing worthy of a separate corrigendum.

Using Kaufman as a 'moral lesson' for Mann, as some are trying to do, is thus wholly inappropriate.

I don't agree. As an aside,

I don't agree. As an aside, Kaufmann did not use the whole record. He eliminated the contaminated portion. He also made an error with regards to calibration because of this.

Upon being made aware of the error, he assigned someone to look at McIntyre's claims, and discovered that the error is as McIntyre claimed. This was seen in the ClimateGate e-mails.

Mann appears to have done nothing like this, despite a published comment from McIntyre. We even see a repeat of the upside-down usage in 2009, after Kaufman's correction of the issue.

Martin Vermeer

Martin Vermeer said:
"Jokimäki is a bit harsh on McIntyre."

Well, I'm sorry about that. I guess it arises from looking at McIntyre's claims and accusations towards climate scientists and how those claims seem to turn out to be false almost every time. Deep Climate has just exposed another one:

Sure, generally agreed. But

Sure, generally agreed. But in this case he had a valid point (though by no means a closed case), which he just completely messed up presenting. One almost feels sorry for him, käy melkein sääliksi ;-/

"käy melkein sääliksi

"käy melkein sääliksi ;-/"

Yes, almost... :)

Arthur, you conclude your

Arthur, you conclude your 6/30/10 post Michael Mann's errors with a reference to this post. You say,

People make mistakes; as long as they correct them when the error is detected, it's really not such a big deal. The question I raised in my "Where's the fraud?" post was whether there was any substantive error of some sort that had not been admitted or corrected after exposure.

Could I pose these questions?

1. In your view, was there any substantive error in Mann08 with respect to that paper's treatment of the four Tiljander proxies?

2. In particular, Mann08's methods describe the calibration of the four Tiljander proxies to the instrumental temperature record, 1850-1995. I have claimed that these four proxies are not calibratible. What is your conclusion on this point?

3. If you think that Mann08 was in error on the calibration of the Tiljander proxies: in your view, have the authors of the paper admitted the error? Have they corrected the error?

Now that you have looked into the matter, a summary of your views would be a nice ending point (maybe?) for this thread.

As I said, I have *not*

As I said, I have *not* looked into these matters for myself, I have read only other people's comments. I'm now commencing to look. I'll make my conclusions clear, when or if I ever reach any, on the other post (or in a later post).

Arthur, my comprehension was

Arthur, my comprehension was off when I read "Michael Mann's errors" this morning--apologies. As you say in that post, you're continuing to look.

I don't think the

I don't think the relationship between temperature and the Tiljander sediment proxy in the pre-instrumental period is entirely clear, the original researcher's interpretation notwithstanding.

Kaufman's solution makes little sense. Even if one is convinced that the true relationship is opposite to that seen in the modern instrumental period (because of human contamination), Kaufman's method of calibration to other proxies (when calibration to the instrumental period is not an option) seems dubious. Better to eliminate it altogether.

Mann et al is different. To me the issue is that the automated screening process does not deal well with contamination of the proxy in the instrumental period, especially for a proxy type subject to a two-sided test. Should there be an ad hoc screening to deal with such cases?

Yes, I guess that's another

Yes, I guess that's another open question for me, whether Mann's "screening" method could be improved somehow by looking at this case in a bit more detail...

I have been busy for the last

I have been busy for the last week or so (in part due to my birthday), so I never got to follow up on my last post. It seems this site has picked up in activity since it, and I'm not exactly sure what I should discuss. As such, I think I will limit myself to the topic at hand.

To be honest, I don't get the obsession people have with "fraud." In the simplest sense, would it matter if a person's work is "fraudulent" rather than just "stupid"? Does it matter if Mann's issues came from dishonesty rather than incompetence? On some levels, yes. But for the most part, why worry about it? Wrong science is wrong. If something is found to be wrong, it should be pointed out and fixed. All the constant nagging from "auditors" happens because people don't do this.

Two comments caught my eye as I skimmed this page. The first was from our host:

"Because if there's no fraud, then what's all the fuss about? People being sloppy? Even though it makes absolutely no difference to the results? Really?"

Now obviously, not everyone will agree "it makes absolutely no difference to the results." If we remove just the Tiljander series, nothing really changes. This leads to a point highlighted in a comment by Martin Vermeer:

"The main, unrelated change is the addition of the 'both dodgy proxies and all tree rings removed' curve. It is a living demonstration of denialism in action: the usual suspects, seeing that neither dropping the "dodgy proxies" nor dropping all tree rings made the thing break down, of course wanted to grasp at straws and demanded "but what if you drop both?"

This is the sticking point. The first thing I want to note is the statement I made bold is ridiculous. Problems have been raised with two different sets of proxies. Performing a test which removes only one of the two at a time does nothing to alleviate concerns. It is not "grasping at straws" to ask what happens when all questionable series are removed. It is sensible. So what does happen? Martin Vermeer continues his comment by claiming:

"Well, the buzz trickled through to Mike Mann -- sometimes it does -- and nice guy that he is, produced a bonus curve, courtesy of Penn State... looking of course completely predictable. [Yawns, and suppresses sarcastic remark.]"

Here too, a sneering tone directed at critics belies a serious problem. The problem being, he is wrong. The graph made with all the questionable proxies removed does not show a hockey stick. The difference between "hockey stick" and "no hockey stick" is obviously quite severe.

The situation is simple. There are two sets of proxies which are untrustworthy. The first set is bristlecone proxies, which are known to have issues. This has been discussed ad nauseum. Indeed, even the NAS has even said bristlecone proxies should be avoided in temperature reconstructions. The second is the Tiljander series. One of two things was done with this series. The first possibility is it was used "upside down." Obviously, that is inappropriate. The second possibility is the authors of Mann's paper disagreed with the original authors' position on the series' correlation. While this would not be wrong on its face, the authors never said a word about it. If it was done, it was done in complete secrecy, which is obviously wrong.

Talking about "fraud" may be useful for some things, but it seems to be missing a simple point. Mann's paper is bad. Its conclusions require you include bad data. You can include bad data series number one, you can include bad data series number two, or you can include all the bad data. As long as you throw bad data in there, you get Mann's results.

The takeaway point of all of this is if you don't use bad data, you don't get his results. Nobody has admitted this.

Well, if Mann knowingly and

Well, if Mann knowingly and repeatedly used "bad data" then that was wrong, and if it materially affected the scientific results as you suggest here, that definitely falls under the category of scientific misconduct, or basically fraud. The question is whether there is sufficient evidence that he did those things. Which I plan to look into.

I think you are focusing on

I think you are focusing on the wrong issue. Does it really matter if Mann used the same "bad data" again? As we've seen with the Tiljander series, it is possible to find other "bad data." Is his work somehow more trustworthy if he goes out and finds new "bad data" rather than reusing the old?

The point should be Mann's original work, and all subsequent hockey sticks, have originated from a few select sources. While they can talk about how much data is being used, the conclusions ultimately lie in just a few data sets. One of the biggest points discussed when Mann's 2008 paper came out was just how many proxies were used. Nobody has admitted the conclusion of the paper depends on just a tiny fraction of them. All the others basically just serve as a smokescreen to hide this.

Is it fraud for people to keep using bristlecone proxies in temperature reconstructions? No. They will argue while the data has been called into question, there is no conclusive proof the proxies are "bad." Moreover, they will argue the inclusion "doesn't matter." After all, they can still get the same results without them. They just have to find more bad data. After all, it wasn't fraud with Tiljander because they didn't know the data was being used incorrectly.

This is why I think the focus on "fraud" is uncalled for. There are all sorts of legal issues when dealing with scientific fraud which will just serve to cloud issues. The issue should be the science behind the hockey stick is bad, and the scientists aren't admitting it.

Brandon, I'm not trying to

Brandon, I'm not trying to get into "legal" conclusions of fraud, it is absolutely the science (what is conclusively known about it now, and what was at the time) that I'm trying to understand. If there is a real objective problem - and you have stated another possible one here:

the conclusion of the paper depends on just a tiny fraction of them. All the others basically just serve as a smokescreen to hide this.

then what you are calling a "smokescreen", if real, sounds like data falsification. So that would be another thing to investigate, in addition to the Tiljander issue.

Here's my problem - people put up dozens of slightly different claims about what Mann and others have done, but rarely do they seem to get very specific about it. Much of it boils down to opinion about choices that could have been made one way or another by any reasonable person at the time. The question is which, if any, of these many many claims actually points to something that indicates deliberate concealment or fabrication with impact on the scientific conclusions, if any such thing ever happened. Be very specific in what you are claiming the problem is, and I'll try to look into it to see whether it holds up.

The issues with Mann and his

The issues with Mann and his work have been going on for about a decade. There are a lot of aspects involved. It is hard to keep up with all of them, much less explain them. It wouldn't be possible to list and explain all the grievances in a post on a blog. While I agree people should do a much better job of explaining things, I can also understand why they don't. Perhaps the best approach would be not to try to cover everything, but to instead focus on single issues at a time. In an attempt to try this approach, I will discuss an issue which arose in Mann's original work.

In this work, Mann reported good RE verification for his reconstruction to show it was "skillful." In the caption of one of his figures, he also reported a good R2 verification score for the 1820 step of his reconstruction. However, it turns out Mann's reconstruction fails R2 verification at an earlier period. He did not report this. When Steve McIntyre made an issue of it, Mann claimed to have never calculated R2 verification for his reconstruction. Years after the work was published, (some) code and data was was publicly archived by Mann. This code clearly showed Mann calculated the R2 verification.

Mann repeatedly denied ever calculating R2 verification for that reconstruction, in many different places. Indeed, he even denied it when testifying in front of an NAS panel. This denial flies in the face of his code, as well as the fact his paper reports the R2 verification score for one portion of his reconstruction. Despite being such an obvious lie, nobody called him out on it. I think that gives a pretty good example of why people are bothered by the state of climate science. The work which started the hockey stick craze was only included in the IPCC report because the author withheld adverse verification statistics.

Incidentally, I think "fraud" gives the impression of the legal issue, and that is why a lot of people want to avoid the term.

Your accusation doesn't make

Your accusation doesn't make sense. How can any "code clearly show[...] Mann calculated the R2 verification." You have to actually run code and save the results in a place you would look at for that to be a valid argument. Has that been proved? If not, why all the doubts about what he said? I mean, this isn't even "he said, she said", this is "he said, but we think he should have said"...

Let's stick to the most recent cases, unless we really have full and complete context and details on a case.