Steve McIntyre takes Lewandowsky’s statistical screed to task and writes:
Lewandowsky’s most recent blog post really makes one wonder about the qualifications at the University of West Anglia Western Australia.
Lewandowsky commenced his post as follows:
The science of statistics is all about differentiating signal from noise. This exercise is far from trivial: Although there is enough computing power in today’s laptops to churn out very sophisticated analyses, it is easily overlooked that data analysis is also a cognitive activity.
Numerical skills alone are often insufficient to understand a data set—indeed, number-crunching ability that’s unaccompanied by informed judgment can often do more harm than good.
This fact frequently becomes apparent in the climate arena, where the ability to use pivot tables in Excel or to do a simple linear regressions is often over-interpreted as deep statistical competence.
I mostly agree with this part of Lewandowsky’s comment, though I would not characterize statistics as merely “differentiating signal from noise”. In respect to his comment about regarding the ability to do a linear regression as deep competence, I presume that he was thinking here of his cousin institute, the University of East Anglia (UEA), where, in a Climategate email, Phil Jones was baffled as to how to calculate a linear trend on his own – with or without Excel. At Phil Jones’ UEA, someone who could carry out a linear regression must have seemed like a deity. Perhaps the situation is similar at Lewandowsky’s UWA. However, this is obviously not the case at Climate Audit, where many readers are accomplished and professional statisticians.
Actually, I’d be inclined to take Lewandowsky’s comment even further – adding that the ability to insert data into canned factor analysis or SEM algorithms (without understanding the mathematics of the underlying programs) is often “over-interpreted as deep statistical competence” – here Lewandowsky should look in the mirror.
Lewandowsky continued:
Two related problems and misconceptions appear to be pervasive: first, blog analysts have failed to differentiate between signal and noise, and second, no one who has toyed with our data has thus far exhibited any knowledge of the crucial notion of a latent construct or latent variable.
In today’s post, I’m going to comment on Lewandowsky’s first claim, while disputing his second claim. (Principal components, a frequent topic at this blog, are a form of latent variable analysis. Factor analysis is somewhat different but related algorithm. Anyone familiar with principal components – as many CA readers are by now – can readily grasp the style of algorithm, though not necessarily sharing Lewandowsky’s apparent reification.)
In respect to “signal vs noise”, Lewandowsky continued:
We use the item in our title, viz. that NASA faked the moon landing, for illustration. Several commentators have argued that the title was misleading because if one only considers level X of climate “skepticism” and level Y of moon endorsement, then there were none or only very few data points in that cell in the Excel spreadsheet.
Perhaps.
But that is drilling into the noise and ignoring the signal.
The signal turns out to be there and it is quite unambiguous: computing a Pearson correlation across all data points between the moon-landing item and HIV denial reveals a correlation of -.25. Likewise, for lung cancer, the correlation is -.23. Both are highly significant at p < .0000…0001 (the exact value is 10 -16, which is another way of saying that the probability of those correlations arising by chance is infinitesimally small).
These paragraphs are about as wrongheaded as anything you’ll ever read.
Read the rest here at Lewandowsky’s Fake Correlation
I’m not a professional statistician, but I have used statistical techniques extensively in my research and know that it can be missused. Around 45 years ago I wrote an award winning paper on interpretation of experimental data that has been included and maintained in a handbook now in it’s third edition. http://books.google.com/books?id=8C7pXhnqje4C&pg=PA83&lpg=PA83&dq=fred+h.+haynie+statistics&source=bl&ots=tpEUeDItOc&sig=cfZfkW3QZd_3r-N4XyzleWkz_E4&hl=en&sa=X&ei=2clZULK5KIue8QS8mYGQAw&ved=0CDIQ6AEwBA#v=onepage&q=fred%20h.%20haynie%20statistics&f=false
It presents the basics of using statistical techniques that Lewandowski does not seem to understand. Another way of finding that paper is to google Fred H. Haynie +statistics.
The video is gold, Jerry… Gold! This guy is listening to his own voice…
With apologies to Humpty Dumpty: “The data mean precisely what I intend them to mean, neither more nor less”
Chris B says:
September 19, 2012 at 6:40 am
Lews notes to self: 1.Work on understanding Stastics.
2. Work on Acting.
#, Use less starch.
Yikes!
What a prat! How can a scientist sceptical of AGW get his or her paper peer reviewed & published if other scientific prats elbow their papers out of the peer review system because they don’t want them aired in public. Therefore publishing said paper on the internet where it can be peer reviewed by millions & millions, sceptical & otherwise, expert or not, for free!! Seems far better to me than publishing in discriminating journals! Oh & what’s with the Lloyd Grossman impression?
“The science of statistics is all about differentiating signal from noise.”
The signal here is that we skeptics are noise and the CAGW crowd is the signal. Playing little insults to those who have the nerve to disagree with the settled science.
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Besides the recognition of what is noise and what is signal, there is another serious problem in data analysis, the lack of sampling theorem of Nyquist-Shannon. When studying Paleoclimatology, more specifically ice cores, dating of the top and bottom of the samples have ranges 200-400 years (http://www.ncdc.noaa.gov/paleo/icecore/antarctica/domec/domec_epica_data.html). In the process of gas analysis, integrates the sample obtaining an average. This average not represents the extremes, ie if there has been an event Henrich the signal is filtered. If we compare the data from EPICA Dome C or Vostock with GRIP or NGRIP data it is evident (http://www.gfy.ku.dk/~www-glac/data/NGRIP_d18O_50yrs.txt).
The problem is that VOSTOK or EPICA are taken as the record of the climate over the past 400 ky BP (# http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/wg1/072.htm fig223) and GRIP / NGRIP (samples ~ 20 years) only 100 ky BP.
Colin Porter says:
This is the first time I have looked at a blog post by Lewandowsky and Oberauer, and so I don’t know if any one else has made the comment, But what on earth is Lewandowsky doing in creating a post on what he perceives to be a Sceptic V “Realist” attitude to interpreting time series data in a discussion which is supposed to be about detecting the signal from noisy data?
What he is doing is his schtick.
In his Internet Survey paper, he takes fake data created by warmists pretending to be sceptics and uses it to draw unflattering conclusions about sceptics.
The SKS blink chart is a fake chart created by a warmist pretending to be a sceptic and he uses it to make unflattering conclusions about sceptics.
Its what he does.
That, and call people “conspiracy theorist”.
Typical witch doctor turned propagandist.
“…Blog analysts have failed to differentiate between signal and noise…” –Stephan Lewandowsky
Lewandowsky’s paper is 100% noise, 0% signal. It should never have been accepted for publication. But then, this IS climate science, the only hard science with a proud tradition of non-replicability.
Chris B says: “http://www.shapingtomorrowsworld.org/about.htm.
About Us; Mission Statement….”
Should have been called “shagging tomorrows world.”
First this is not science it is pseudoscience. Second mathematics is not science it is a tool that is used in science and lots of other applications too. None of this is science because it is founded on a priori reasoning. It is very had to believe an educated person could be so stupid unless that person had some conspiratorial agenda. It is sad and unfortunate that so much time and resources are being wasted by this foolishness. This kind of junk is often fostered by the extreme ideologists on any and all sides of a question as a smoke screen to obfuscate the truth of the matter.
I agree this Lew’s paper is garbage, but even if it wasn’t.. who cares? What would it prove either way that some skeptics believe in pop culture conspiracies? Mann et al. apparently believe in the “big oil funding of skeptics” conspiracy. I have warmist friends that believe in the “grassy knoll” and even that the moon landing was staged. And what about all these people’s beliefs in one religion or another? Could any correlation between those observations prove or disprove the hypothesis of AGW or anything else for that matter?
And remember, correlation is not causation.
I remember back in 2005/6 a co-worker at Boston Scientific, who had worked for General Mills for 30 years doing D.O.E. (Design of Experiments) asked me why we used TABLES for computing the “F distribution” and then finding “p” values for significance.
I brought in my most involved Statistics book which gives all the analytical formulas for the various distribution functions which are commonly used. (Look here for the F distribution…
http://en.wikipedia.org/wiki/F-distribution)
I laid out the equation, used MATHCAD to do both symbolic reduction and numerical analysis.
I took some data he had, and put it into the correct forms and derived a “p” factor of .96…he said, “That’s wrong…it should be less than .05!” Then I pointed out the 1 MINUS in the formulation, and he realized we’d gotten almost EXACTLY the value we had from the tables.
I then pointed out the time. An hour and 1/2 from when we had started. “Charlie, how long does it take you to us MiniTAB or the Tables to get to this value?” Charlie said, “About 2 minutes.”
And this took us??? Charlie thought, “Wow, and hour and 1/2…!!!”
I lost my best book for a MONTH as Charlie borrowed it to “bone up” (the book discusses the BASIS for the distributions, the derivation of the formulas, and the proper circumstances to use them…)
When you start doing “closed form” integrals on Gamma functions, Error functions and the like, it gets pretty hairy!
What tells me that LEW would be totally LOST within MINUTES if I sat down with him and discussed the TRUE BASIS for the statistics he THINKS he understands?
Max
Lewandowsky needs Auto Tune to rid himself of the pompous nerd affect.
Is there a Doctor in the house who can decipher the micro-emotions Lew is machine-gunning at the camera in his bizarre clips?
Note to Lew:
If you want to embarrass all of the detractor/critics, free the data !!!
Any reasonable person, on hearing that someone with Steve McIntyre’s proven track record had shredded his statistics, would go very, very quiet, and start a frantic correspondence with Steve to get it right.
That’s all.
jorgekafkazar: I think it is more like 150% noise, as Dana might say.
Dana & the CSRRT?
Let’s take the CSRRT’s mission as rapid response to all things skeptic, but not credible response; which probably explains Dana’s incompetent rapid responses wrt PBS hosting Anthony.
John
No Lewandowsky, the conspiracy theorists are on your side. The warmie side. Those that are most likely to believe in Roswell UFO’s, grassy knoll shooters, faked moon landings, 9/11 WTC inside job by Cheney and the Jews, will also believe in Global Warming from the magic molecule. This is Roseanne Barr and occupy Wall Street IQ level. They are Socialist malcontents, hardwired in their DNA to accept government control. They are your target audience.
A fact frequently becoming apparent in the climate arena, is that carrying the title ‘professor’ is often over-interpreted as implying deep scientific competence.
An interesting thing about many CAGW zealots (as opposed to those who have one way or another been honestly convinced that CAGW is a present danger), is they are, almost to a person, so naive about how the internet works. They appear to have no idea that when they are trying to baffle, give a snowjob or present simplistic or clumsy theory to people or pontificate about issues, techniques, science, data, logic,…on a blog, they are presenting their stuff and reputations to, among the many, some highly intelligent, top- of- the- line practioners who dwarf the expositor’s comparatively puny capabilities. They clumsily hide declines, fudge data, hide data, dispose of data, manipulate data, cherry-pick and amaze themselves with their analytical prowess in front of giants. This correlation between zealotry/hubris and naivete is more telling of the person than their theory.
He is at it again – another blatantly misleading press release “Childhood vaccines do not cause autism. Barack Obama was born in the United States. Global warming is confirmed by science. And yet, many people believe claims to the contrary”
see http://www.eurekalert.org/pub_releases/2012-09/afps-mps091912.php
Peter
I don’t know why we are all getting uptight. This seems like a very typical climate consensus paper as far as I can tell. Think about it.
Lies … damn lies …… and statistics
Michael Mann tweeted support for Lew a bit too soon, or maybe the Manniacs just can’t help supporting bad statistics and misrepresentations of bad statistics: yikes, that Lewandowsky fella is really not looking so good in his latest pretensions to competence:
Climate Audit demolishes Lewandowsky…. again