Sunday, September 24, 2006

Are scientists biased?

One of the parts of the Wegman report that I objected to was his characterization that scientists are biased towards getting results that confirm the underlying paradigm of AGW:
there is a tightly knit group of individuals who passionately believe in their thesis. However, our perception is that this group has a self-reinforcing feedback mechanism and, moreover, the work has been sufficiently politicized that they can hardly reassess their public positions without losing credibility.
What this idea overlooks is that one gets ahead in science not by agreeing with previous work, but by advancing new ideas. The bigger the new idea, and the bigger the old idea that it replaces, the more fame and success accrue to the scientist. Look at famous scientists through history and you won't find a single one that got there by agreeing with the prevailing wisdom.

If you're a member of the so-called "hockey team," you're not going to get much credit or respect from the community if all you do is agree with hockey stick. Rather, an individual scientist will do much, much better if he can show that his competitors' (aka colleagues) work is faulty or biased. And that same individual scientist will do much worse if his or her work is viewed as faulty or biased. This incentive to destroy previous work explains why, in any group of a few scientists, there will be at least two that hate each other.

Scientists are human and all of us have personal biases. But because scientists know that important ideas they advance will be re-tested by other scientists, there is a strong incentive to be careful and conservative in their claims.

People that argue that there's some type of "conspiracy" among climate scientists to increase funding by producing "alarmist" science are either a) a clever advocates trying to obstruct AGW policy by attacking the science or b) someone who doesn't understand science.


coby said...

Hi Andrew,

I agree with your broader points. However I think that in the very isolated case of the Hockey Stick, the highly charged political nature of the issue and the fact that the criticisms came from outside of the community (not just dendrochronolgy but climate science as a whole) make the accusations of "insiders toeing the line" more plausible than the broader attacks on all of climate science.

Let me quickly say (probably not quick enough!) that that may make the accusation plausible, but it by no means proves that any such bias occurred. I would also add that enough time has passed now and enough subsequent studies have validated the general conclusions of MBH that we can safely conclude that understanding of past climate is advancing as it should be.

Anonymous said...


remarking to the broad sense only..

twas very interesting to have you posit science the construct of curiosity constrained by criticism..

for which my tks.


hswiseman said...

My opinion:

Wegman's speculation about peer influnece derives from his stunned incredulity that the defective statistical basis for the Hockey Stick work drew no adverse commentary from the Climate Science community until some geologist figured out that some sort of data mining had occured. Further digging then discovered that a vital part of the proxy network (bristlecones) is a CO2 sensitive species with inadequate temperature sensitivity. No one seemed to question this either, even though the
bristlecone literature explicitly cautions about drawing temperature relationships. His suspicions may be incorrect, but they are not entirely unjustified.

Then we have this from Dr. Pielke Sr. today

"Of most concern to those who value courteous scientific debate, however, is the quote from Jim Hansen. It reads

”Some of this noise won’t stop until some of these scientists are dead,” said James Hansen, head of the Goddard Institute for Space Studies in New York City, and among the first to sound the alarm over climate change.”

Regardless as to your perspective on climate change, this callous statement from a federal administrator who is very visible in the climate science debate should be strongly repudiated by everyone who accepts that the debate should be about the science. I invite Dr. Hansen to expand on, clarify, or correct the comment that he made for this news article."

The patriarchs of the climate change movement obviously brook no dissent. Which may explain why there isn't any.


Howard Wiseman

Anonymous said...

Well said Mr. Wiseman, and the bias in the climate science and computer modeling community is pronounced and obvious to anyone who talks to these people on a regular basis, as I do. They feel they are on an almost religious crusade to save the world, this is not science as usual, this is the nexus of science, politics, and religious/environmentalist fervor. I can have rational, logical conversations with my associates about all scientific theories and hypotheses save this one. I always get the feeling I am talking to a zealot when this subject comes up, the yelling, the shouting down of any others' data that questions AGW, the wild look in the eyes, all tell me this is not about the science. Personal bias, as Dr. D alludes to here, is rampant in this subject, since it is no longer science, it has been highjacked and tainted. All of you climate scientists out there need to deeply examine your biases and motives here, they are too obvious to us non-aligned scientists observing you. And many observant, thinking members of the public rightly reject zealotry of all kinds, thus you do your cause no good.

EliRabett said...

Howard Wiseman has clearly not read the first comment to Pielke Sr.'s post. What Hansen said is simply a restatement of Planck's observation about theories not making converts, but becoming accepted only after its oldish opponents have shucked the mortal coil.

Dr. J. I am sure talks to many people who run global climate models between his frequent testimony to the US Congress. Such a busy life. However, I suspect he is much happier with those who run smaller scale models.

Anonymous said...

Very interesting how Hansen is now attacking the skeptics so forcefully, in 1998 in a debate with Pat Michaels, he said this:

"Also, I want to be clear that I believe that greenhouse
sceptics like Pat, Dick Lindzen and others, overall, I think they’re a benefit to the
science of the climate change debate. Science actually thrives on questioning and dissent
and that’s the nature of science."

I guess he has gotten frustrated that they are still alive?

Anonymous said...

Or you can choose the middle ground Dr. D. You can publish a new idea (or graph) that agrees with the popular theory and can be used by proponents of the popular theory to beat their colleagues (competitors) over the head. Then you don't archive or publish any of the data that your idea (or graph) is based on. You are guaranteed the support of the people advancing the popular theory, because your work agrees with them. And when your colleagues (competitors) challenge your work, they won't have access to your data to attack the premise of your idea (or graph). Sound familiar? Thats how the hockey stick came about...and that is a pretty close approximation of how the debate about it went down. It may not be a true conspiracy in that nobody planned their subterfuge ahead of time...but the political symbolism of the hockey stick became so strong that to abandon it would have left AGW proponents fighting an uphill credibility battle even if their own science was sound and well regarded. So they defended it...and left themselves open to alot of criticism, because the politics of what they were doing overcame the science.

hswiseman said...

Human influences on climate forcing is an important subject for study. (Is the climate truly warming? Is it caused or influenced by CO2, aerosols, carbon black, solar output, sulphuric acid, methane, land use, etc? If so to what extent? Does the ocean react differently from the atmosphere? Does the atmosphere react differently at different levels and different latitudes? Can the models be verified through predictive accuracy? If not, how can we improve our knowledge? Can we trust our instruments? The list goes on and on, and not because of some political agenda to discredit the research of a couple of scientists, but because this is how science works-through inquiry and continous doubt) But we will not find anything resembling the truth by presuming outcomes before valid data is defined and analysed. Scientist who respond to legimate inquiry on data integrity and methodology with angry outbursts, threats and insults while disdaining true scientific discourse are to be viewed with suspicion.

Dano said...

Scientist who respond to legimate inquiry on data integrity and methodology with angry outbursts, threats and insults while disdaining true scientific discourse are to be viewed with suspicion.

That's the constructed narrative. Who constructed that narrative? The folks who published work before showing it to the authors they were disparaging. Not very discursive.



Andrew Dessler said...


My point is that publishing a plot that agrees with the current wisdom does little for your career. If you want to make it big in science, you need to tear something down. Thus, there's little incentive to agree and lots of incentive to disagree --- which explains why scientists tend to be pretty disagreeable.


David Graves said...

My late father had an uncle by marriage, T.J.J. See. Early in his career, he showed great promise as an astronomer. However, for reasons of personality and character I still do not fully understand, he refused to accept the revolution in cosmology wrought by Einstein and the insights into atomic structure discovered by E.O. Lawrence at Berkeley. He lived to be 96 and to his dying day held to his beliefs. His is the kind of case that Planck cites and why Thomas Kuhn quotes Planck. There is nothing, I repeat nothing sinister or threatening in what James Hansen said. It is a reflection of the fact that science is a product of the human animal. Speaking of animals, call off yer dogs, Mr. Wiseman, and admit that Pielke Sr. misunderstood a perfectly reasonable comment, and you used it as a pretext to beat those you disagree with about the head and shoulders.

Anonymous said...

I understood your point perfectly Dr. D and I agree with most of it. My point is that the reverse of your thesis is also true. When somebody comes along and tries to attack the prevailing theory, the scientific lives and reputations of its proponents are potentially on the line. So just as somebody new can get farther if they tear down an existing idea, somebody who came up with the existing theory has a vital personal interest above and beyond their scientific interest in seeing that it is not overturned by somebody new. In other words, they have more than a purely scientific interest in the failure of the competing theory.

I am not in this post or in my previous one saying that I think Wegman is right about there being a "conspiracy" or intentional bias. I think the hockey stick is just a unique case in that it is a relatively unimportant piece of science on the whole that isn't really groundbreaking in attempts to prove or disprove AGW. However, it has been (ab)used outside of the scientific community as the holy grail and smoking gun of AGW put together. Its political importance outside of the climate science community far outweighs its importance to the science of GW. Because it has became such an icon of AGW politically, many of the scientists involved appear to feel compelled to defend it, even though the creators of it have (at the least) failed to follow standard scientific protocol by not archiving the raw data that they used for their work and possibly have cherry picked data sets that support their hypothesis. The point being that there is no logical scientific incentive for respected scientists to defend other scientists who are doing sloppy work simply because they share a similar view on a given theory. I see it more as political expediency, while Wegman sees a conspiracy or evidence of bias. If the hockey stick is proven to be flawed, it doesn't mean that AGW as a theory is wrong. But it would be a political black eye to folks like Al Gore and others who have wielded it mightily in the political arena fighting for action against AGW.

Anonymous said...

Good points Bill F., I remember Sen. John McCain, a normally rational and thoughtful person, looking agast at the pictures of melting ice caps and glaciers during his first hearings on the failed McCain-Lieberman Climate Act, and stating that the pictures and his trip to Alaska "told me all the science I needed to know about global warming". As they say, a picture is worth a thousand words (even if those words are falsely implied), and the abuse of the hockeystick and other "visuals" have not helped science and they are certainly not the scientific method at work. This is just politics.

Anonymous said...

you said,..."there is a strong incentive to be careful and conservative in their claims."

Conservative? I thought all climate scientists were left wing wackos, now you say this? I am confused.


hswiseman said...

Perhaps we should let Dr. Hansen speak for himself. Maybe he will walk the planck. While he's at it, he can declare Hansen's Inconstant, explaining how the weak predictive value of his work is actually strong proof of the AGW thesis.

Andrew Dessler said...

Howard W.-

First, "walk the Planck" is hilarious. I'm going to use that in class tomorrow.

Second, I'm interested in why people seem to think that Hansen's predictions have not panned out. This is like the story that if you drink Coke and eat pop rocks, you'll explode. Urban myth. See Hansen's recent paper in PNAS (here).


EliRabett said...

George Landis raises the issue of what has changed since Hansen said in 1998 that denialists such as Michaels, Singer et al were useful as part of the climate change debate.

Eight years and a lot of invective from the denialists.

EliRabett said...

Andrew asks why people believe that Hansen's predictions have not panned out. He might ask his friend Roger Pielke Jr. Pay attention to James Annan's comments. Eli also considered the problem

It is not in the interest of the denial crowd that there be an example of how such a prediction had been made, and was accurate.

C W Magee said...

Bill F says:
"When somebody comes along and tries to attack the prevailing theory, the scientific lives and reputations of its proponents are potentially on the line."

No they aren't. Nobody has ever lost a job for having a theorem disproven. In Earth Sciences, in particular, the field is young and fast enough that theorems have shorter lifespans than researchers have careers. The only time they hurt someone is when that person decides to cling to a dying theory instead of getting on with research.

Anonymous said...

Obviously, Dr. Pielke answered Dr. D's question quite well. I know many "predictive" types in various fields (economics, environmental science, biology, weathermen, etc.) who routinely make numerous "scenario" forecasts, and like the TV weatherman who says there is a 30% chance of rain, he is always right, if it rains he said it had a chance, and if it doesn't he said it might not. So Hansen is no better than that in his scenarios, he can always claim one of the numerous ones if right when you make such broad, vague claims, but does that make him a Nobel Prize contender??? So What?

Anonymous said...

What the people arguing that there is genuine dissent among "climate scientists" seem to skip over or do not understand is that the majority of the deniers are not climate scientists (Ball, Singer, Seitz, McIntyre etc.) and are not publishing in the peer reviewed scientific literature and secondly, they are not truthful in their statments and arguements.

There is a need for serious debate in many scientific fields but when one side is dominated by untruths, obfusction, quote mining etc. it is obvious that the scientific debate is over.

Ian Forrester

EliRabett said...

Dr. J. might want to take a look at the latest "inaccurate" state of Hansen's prediction.

Right on the money. Hard to argue that when the weather guy says its is going to rain, it rains.

Anonymous said...

Very true Dr. J, with all the vastly different scenarios, he can't ever be wrong. It reminds me of the business consultants we used to hire, the old saying was that if you throw enough "dung" against the wall, some is bound to stick sooner or later.

Andrew Dessler said...

It sounds like even the most skeptical around here are not arguing that Hansen is WRONG, just that we cannot say he's RIGHT. That's an interesting evolution of the argument.

EliRabett said...

Actually Andrew, if you look at the paper, (and the link that I provided has not only a link to the paper but a copy of the graph showing the prediction and the observations, and if you click on the graph you get a larger better quality graph) you see that any honest person MUST say that Hansen was right.

The worst you could say is that there were somewhat compensating assumptions in the calculation. However, as I point out, even though there might be a relatively large error in climate sensitivity, the practical effect is small when the change in CO2 concentrations is only ~1/10 of doubling.

This is something that Hansen has always known, and Roger Pielke Jr. does not. For small changes in inputs, the change in outputs are always linear. The exception would be for partially chaotic systems near a bifurcation. Pray that we are not near a climate bifurcation.

Hanson provided three scenerios. He stated that one of them was the most probable. That is not a lot of scenerios.

The global temperature IS following the one that he said was most probable. That is a prediction that has been validated.

To claim otherwise is to raise denialism to new levels.

Anonymous said...

The skeptics use the same tactics all the time. For a very good satire on these skeptics here's a link to the "the moon is not real" page:

But don’t all qualified scientists and astronomers agree that there is a moon? Indeed, but shouldn’t one be suspicious of such unanimity, when universities are supposed to be forums for open debate of controversial issues. Even a layperson like myself knows that scientists are not supposed to approach issues with preconceived notions. Yet this principle is cast aside when the moon is at stake. You will never see the revisionist perspective on the moon being taught in institutions of higher learning, even as a controversial opposing view. In fact, in order to even become a recognized scientist in the current atmosphere of academic repression, one must pay lip service to the establishment’s orthodoxy. Could you imagine a student who argued the revisionist viewpoint on the question of the moon being awarded a degree? He would be hounded out of the university in an instant! How can one explain such behavior from institutions that are supposed to serve as forums for the free exchange of ideas, except to conclude that the establishment has something to hide?

Dano said...

It sounds like even the most skeptical around here are not arguing that Hansen is WRONG, just that we cannot say he's RIGHT.


The denialists pretend they don't know what scenarios are so they can continue to harrumph. It's the only way they can get play, Andrew.



Hank Roberts said...

I tried to interest Dr. Peilke Jr. in this article -- for those of you having access to Science, it's 3 pages, and worth some consideration when discussing predictions or forecasts.

Quoting from:
(Where Dr. P.Jr. posted a draft Dr. H. circulated for comment -- one that I think was an early version of his recent PNAS article, which see also).

I'm interested in how Dr. P.Jr. discussed Hansen's draft, with respect to whether there's a bias showing back then, and how it looks now.

I asked for comments on this there recently (no response yet there):

Peter Lipton's review article in Science 307, 14 Jan. 2005 at 219-221
Title is: Testing Hypotheses: Prediction and Prejudice

"Observations that fit a hypothesis can be made before or after the hypothesis is formulated. Can that be relevant to the amount of support that the observations provide for the hypothesis? Philosophers and statisticians are both divided on this question, but there is an argument that predictions ought to account more ...."