Re: Cohen's erroneous statements

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

On Fri, 11 Jan 2002, Rad health wrote:



> In response to Dr. Cohen's questions below.

>

> 1.  There are numerous references concerning the glass-based detectors, for

> example see:

>

	--Many thanks for the references.



>

> 2.  Many of the case-control studies coolected information on ETS.

>

> The studies used pack years smoked by other people (other than the subject)

> in the home and they also asked how many people in the home smoked over the

> 30 year period.  This information was used in the multivariate analyses if

> the impact was stistically significant.



	--My apologies for not recognizing this. Do you know if this was

important in affecting the results in any of these studies?



>

> 3. Field's Radsafe posting of March 9, 2000

>

> Dr. Cohen,

>

> As time permits, I would be very happy to work on a joint paper with you to

> discuss how these factors are taken into account in a case-control studies

> versus ecologic studies.  Let me know if you are interested. The paper below

> touches on how these questions are addressed in a case-control study.

> ----------------------------

> Cohen  subsequently indicated he was not interested.



	--I don't remember this, but I also do not see how it is useful.

The two types of study are very different. Field wrote about case-control

studies, and I wrote about my study in the paper "Treatment of confounding

factors in an ecological study" which is posted on my web site.



>

> I would find a paper on this helpful especially since you keep comparing

> your ecologic studies to the case-control studies.



	--I don't compare my study with case-control studies (except in

response to direct challenges). In cases where my study is criticized for

a certain shortcoming that is also present in case-control studies, I

point this out in passing, but I do not put heavy emphasis on it. If you

point out an example in which I have gone beyond this, I will respond more

definitely.





> In the arhives you said

> you can not use an ecologic study to assess the risk posed by radon

> exposure.  It appears you have reversed your position.

>

	--I have not changed my position. It is that you cannot use an

ecologic study to determine the risk to an individual from radon exposure.

I do not try to do this; I test the validity of the linear-no threshold

theory, and find that theory to be invalid. Therefore, if someone uses

that theory to assess the risk to an individual, that assessment is in

error.





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