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RE: Field's comments on Cohen's Observation
Bill,
Dr. Cohen's conclusion is that, absent a valid alternative explanation, the county data is inconsistent with validity of the LNT.
Best regards.
Jim Dukelow
Pacific Northwest National Laboratory
Richland, WA
jim.dukelow@pnl.gov
These comments are mine and have not been reviewed and/or approved by my management or the U.S. Department of Energy.
-----Original Message-----
From: epirad@mchsi.com [mailto:epirad@mchsi.com]
Sent: Mon 6/16/2003 11:57 AM
To: Dukelow, James S Jr
Cc: BERNARD L COHEN; radsafe@list.vanderbilt.edu
Subject: RE: Field's comments on Cohen's Observation
Jim,
Just for the record, what conclusion would that be?
Bill Field
>
> Dr. Bill Field wrote:
> -----Original Message-----
> From: epirad@mchsi.com [mailto:epirad@mchsi.com]
> Sent: Monday, June 16, 2003 9:06 AM
> To: BERNARD L COHEN
> Cc: radsafe@list.vanderbilt.edu
> Subject: Re: Cohen's Observation
>
>
> Dr. Cohen,
>
> <snip>
>
> The reason I enter this debate is not about ego, but rather because so many
> people including knowledgeable HPs and Physicists misinterpret your findings
> to indicate prolonged residential radon exposure does not cause lung cancer
> (eventhough the vast majority of case-control studies indicate it does). You
> have stated yourself ecologic studies can not assess risk. This needs to be
> stated by you more often. While ecologic studies can not assess causality,
> analytic epidemiology studies (such as case-control studies) do have the
> ability to establish causality.
>
> If you would have found a positive ecologic association between radon and lung
> cancer and used that to state this proves the LNT is valid, I would be just a
> fervent in my opposition in you using it to test the LNT because of the
> limitations of the ecologic design. This debate has not been about the
> validity of the LNT, this debate has been about the limitations of ecologic
> studies. You state the limitations inherent in ecologic studies do not exist
> if you use an ecologic design to test the LNT, no knowledgeable epidemiologist
> would agree with such a contention.
>
> The validity of the LNT should be tested, but not by such a weak tool as an
> ecologic study.
>
> I am sure there are many other areas we do agree on, but the proper use of an
> ecologic study is not one of them.
>
> Regards, Bill Field
>
> ====================
>
> Dr. Cohen has always clearly stated the conclusion that he believes his analysis
> of the county data supports and should not be responsible for
> mis-interpretations or mis-representation of those conclusions.
>
> From LNT, it follows as the night the day that radiologically-induced cancer
> incidence (and cancer mortality, given reasonably uniform standards of
> treatment) is a linear function of person-rem exposure. As such, an ecologic
> study is adequate to test the LNT, assuming dependence and confounding issues
> can be handled.
>
> To even suggest that Dr. Cohen might have tried to prove the validity of LNT
> using his or any other data set misunderstands the nature of the scientific
> method, at least in the Popperian formulation. Nature whispers yes and shouts
> NO. An experiment whose results conform to the predictions of a theory does not
> "prove" validity of the theory. It may gives us a warmer feeling about the
> theory. Many confirmatory experiments may lead us to believe to a high level of
> confidence that the theory is true, but they do not "prove" its truth. "Proof"
> is a concept that lives in Mathematics not in Science.
>
> On the other hand, a theory may make predictions that are falsifiable, in the
> sense that we can design and perform an experiment whose outcome is capable of
> contradicting the predictions of the theory. If we were perform the experiment
> and the results indeed contradict the predictions of the theory, then we need a
> new theory. To many, including me, Cohen's dataset and his analysis look very
> much like such an experiment.
>
> Finally, "knowledgeable epidemiologists" believe a number of weird things, case
> in point being Rothman's assertion a while back that epidemiologists didn't need
> to bother with the Universal Null Hypothesis in their consideration of whether
> their data said something meaningful or was simply a reflection of random
> variation.
>
> Best regards.
>
> Jim Dukelow
> Pacific Northwest National Laboratory
> Richland, WA
> jim.dukelow@pnl.gov
>
> These comments are mine and have not been reviewed and/or approved by my
> management or by the U.S. Department of Energy.
>
>
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