Re: Radon and Smoking (individual vs aggregate)

["Otto G. Raabe" <ograabe@UCDAVIS.EDU>]

February 21, 2002



Dr. Field says that the joint distribution between radon levels and smoking

characteristics in each County is what is causing the inverse slope in Dr.

Cohen's ecological studies of radon and lung cancer. Dr. Cohen says he has

been looking for a relationship that could explains his results. Dr. Field

says that it is too late, since those unknown County relationships are

inherently part of the observed results and cannot be removed or corrected.



Well, if the unknown relationships of smoking characteristics and radon

levels by County are totally random among the 116 Counties in Cohen's

study, wouldn't that randomness wash out the effect of individual County

radon versus smoking relationships? Dr. Field's objection would be correct

only if a few Counties where under study. It seems to me that with 116

Counties the only way those individual County relationships could have such

a strong and consistent effect on Dr. Cohen's study is for there to be an

underlying relationship the permeates most of the 116 Counties. Isn't that

what Dr. Cohen is trying to find, a plausible relationship that can explain

his results? 



I can't imagine that random and unrelated within-County relationships

between radon levels and smoking characteristics could produce such a

consistent and robust result.



Otto

 

	*****************************************************

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

	Center for Health & the Environment (CHE)

	(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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