RE: Field's comments on Cohen's Observation

[BERNARD L COHEN <blc+@PITT.EDU>]

On Tue, 17 Jun 2003 epirad@mchsi.com wrote:

>

> You stated that 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.

>

> I have two brief comments,

>

> First, radiologically induced lung cancer is not a linear function as per

> person-rem unless you can describe the population in pretty good detail. For

> example, there are many factors that modify the assumed linearity such as age,

> smoking, etc.



	--All of these have been carefully treated in my papers. Why can't

you give me a concrete hypothetical example of what the problem could

possibly be?



>

>  Secondly, you state that ASSUMING dependence and confounding issues can be

> handled, an ecologic study is adequate to test the LNT"

>

> That is really the heart of the problem isn't it?  Dr. Cohen has not persuaded

> me or from what I can tell most informed epidemiologist and statisticians that

> he has indeed handled effect modifiers and confounders adequately.



	--My procedures for doing this are explained logically

in item #7 on my web site. No one has proposed what may be wrong with that

tightly reasoned treatment



  Dr. Cohen

> has not addressed the within county joint distributions of even smoking and

> radon let alone all the other socioeconomic factors that are also co-correlated

> with smoking.



	--Not true. If you believe this you should be able to give me a

concrete hypothetical example of what I hhave not covered in my treatments



 Because Dr. Cohen uses ecologic smoking information, he can not

> hope to correct for the problem I mentioned above regardless how many attempts

> he makes.



	--If you believe this, you should be able to give me a concrete

hypothetical example of what you say here.



>

> I previously sent Dr. Cohen a possible methodology to address the within county

> joint distribution problems, but he indicated to me that he thought the

> methodology had little to do with his work.



	--If you think there is something wrong with my treatment, you

should explain it. I see no obligation for me to use a treatment you

recommend. Moreover, I could not understand how I could use the treatment

you recommend



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