RS&H

["Jim Nelson" <nelsonjima@HOTMAIL.COM>]

Well, One proof complete>  I guess I at least can now rest my case about 

being attacked by Radiation "Safety" and "Health" if I responded to the this 

question in a way considered politically uncorrect by RS&H.



Jim Nelson



>From: Muckerheide <muckerheide@MEDIAONE.NET>

>Reply-To: Muckerheide <muckerheide@MEDIAONE.NET>

>To: "Otto G. Raabe" <ograabe@UCDAVIS.EDU>, Jim Nelson 

><nelsonjima@HOTMAIL.COM>,        <jim.dukelow@PNL.GOV>, 

><hflong@pacbell.net>

>CC: <radsafe@list.vanderbilt.edu>

>Subject: Re: Risks of low level radiation - New Scientist Article

>Date: Sun, 09 Dec 2001 17:22:44 -0500

>

> > From: "Otto G. Raabe" <ograabe@UCDAVIS.EDU>

>

> > At 09:22 PM 12/6/01 +0000, Jim Nelson wrote:

> >> As I told Dr. Cohen a few weeks ago, I agree with the papers by Smith 

>et al.

> >> that describe the limitations of Dr. Cohen's work.  The smoking data he 

>uses

> >> is so bad, it can only predict a little over 30% of the the lung 

>cancers in

> >> the counties. If there was no confounding, it should be able to predict 

>85%

> >> or so.  I do not call that good control of confounding.

> > **************************************************************

> > December 6, 2001

> > Davis, CA

> >

> > Dear Jim:

> >

> > What do you mean "can only predict a little over 30% of the lung 

>cancers"?

> > Do you mean that a regression R2=0.3? If so, that's only a description 

>of

> > the fraction of the variability that is explained by the regression. The

> > important thing would be whether the trend is statistically significant,

> > not that there is considerable excess variability among the data. Such

> > variability is to be expected in such a study.

> >

> > The key point that Prof. Cohen has shown so well is that the 

>disagreement

> > between LNT and the observations is extremely robust. It is observed no

> > matter how you stratify the data. Just take Colorado as an example.

> > Residents of Colorado annually receive among the highest lung doses in 

>the

> > U.S. from natural radon and its decay products in the air. Meanwhile,

> > Colorado enjoys one of the lowest lung cancer rates in the nation. In 

>1995

> > it was 49 the out of 51. Washington,DC, where radon concentrations are 

>much

> > lower, had the highest lung cancer rate in 1995 (Am. Cancer Society, 

>1996).

>

>Very good synopsis!  But...

>

> > Of course, it is always possible to say that some yet-to-be discovered

> > cross-level confounder could be causing the "apparent" disagreement with

> > LNT, but it does seem unlikely.

>

>Alvarez and Seiler correctly note that this isn't possible. What's a

>"confounder?" A factor that affects a subset such that the results do not

>represent the whole set. Bernie essentially measured the whole set. What

>confounder can fix a "discrepancy" between the whole and itself? :-)

>

>Regards, Jim

>

> > Otto

> >

> > **********************************************

> > Prof. Otto G. Raabe, Ph.D., CHP

> > Center for Health & the Environment

> > (Street Address: Bldg. 3792, Old Davis Road)

> > University of California, Davis, CA 95616

> > E-Mail: ograabe@ucdavis.edu

> > Phone: (530) 752-7754   FAX: (530) 758-6140

> > ***********************************************

>

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