Re: Cohen's Fallacy

["Rad health" <healthrad@HOTMAIL.COM>]

Dr. Cohen,



I really sincerely question that you want to identify the cause of your 

inverse association.  I have pointed out with abstracts the limitations of 

using census data.  Your studies start with questionable averaged data and 

then you use other questionable data to try to stratify to correct for 

confounding.  Why not spend your time trying to improve and understand the 

source of co linearity within a county by collecting information on that 

rather than asking the scientific world to explain your findings for you?



If you believe and others really believe that your one ecologic study has 

shown that the LNT is invalid I can respect your view without agreeing with 

it.  I would just urge you to try to improve your data quality by using SEER 

based incidence data for those states and getting some real data on 

cross-level bias and within county variability.



The one paper I posted shows how blacks are under identified in census data 

along with errors in SES.  There is no way to correctly stratify on a county 

level with this type of data when the stratifiications are based on 

misspecified data.  Black women and men have much higher lung cancer rates 

now because of various behaviors (smoking 20 years ago) and collinear 

correlated factors whose joint affect can not be theorized, but will result 

in inadequate adjustment thus creating a negative association between radon 

and lung cancer. It is up to Cohen to show this is not occurring by 

providing real data on intercounty variability.



  I plan to sign off this list now because of the time required to reply to 

a group of people that support your views.  I was told before signing on the 

list that few people would publicly agree with me if I posted on this site.  

(I had much better luck with Sir Richard.)  That has pretty much been the 

case. It is interesting how the public postings and the private postings to 

me differ.  Why is it all the people who posted to me privately do not post 

publicly?  Are you fearful for your job?   Feel free to log on as Don.  Dr. 

Field, I apologize that I drug you into these "discussions", you were 

correct with your warnings.



This experiment concerning perceptions on the Radsafe list has been very 

informative as compared to the discussions concerning these topics on an IH 

and epidemiology server.  Paper will appear down the road.  Future 

discussions can now focus more on the important topics of the list such as 

hormesis and how HPs can appropriately maximize radiation's beneficial 

effects.  Go for it Jim, Fritz, Mike, Howard, etc.  Please let Norm get a 

post in now and then.



Don







>From: BERNARD L COHEN <blc+@pitt.edu>

>To: Rad health <healthrad@HOTMAIL.COM>

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

>Subject: Re: Cohen's Fallacy

>Date: Tue, 29 Jan 2002 09:25:25 -0500 (EST)

>

>

>On Mon, 28 Jan 2002, Rad health wrote:

>

> >

> > I read the papers and I agree with Field, that you are confusing 

>individual

> > level confounding with group level confounding.  Why not follow Field's

> > suggestion and examine the source of the group level confounding?

> > You have no basis for guessing what the group level confounding is by

> > assuming it is the same as individual level confounding.

>

>	--I do not assume it is the same as individual level confounding.



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