RE: Cohen's Ecologic Studies

[epirad@mchsi.com]

Dr. Cohen,



Just for the record then, how do your treatments account 

for non-linear dependecies within and between counties,  

especially since you are using averaged data for a 

county?



Please be specific.



Concerning the r-squared value.  The fact remains, you 

are able to predict only a small percentage of the lung 

cancer mortality using your smoking rates regardless of 

the cause of your low r-squared value.  



You have also never explained why your radon 

concentrations produce an inverse association with other 

smoking related cancers that are not associated with 

radon exposure.



Bill Field

> 

> On Mon, 3 Jun 2002 EPIRAD@mchsi.com wrote:

> 

> > The bottom line as I have been trying to get across in

> > HP publications for years is that smoking is not a

> > linear function within or across counties in the United

> > States.  If it were, then you could possibly adjust for

> > it better at the ecologic level.

> 

> 	--My several independent treatments of smoking make no assumptions

> about smoking being a linear function of anything

> 

>  As for Dr. Cohen's

> > ecologic analyses, he can account for only about 30% of

> > the lung cancer mortality with his smoking data.

> 

> 	--Wrong, wrong, wrong. The fact that R-squared is only 30% derives

> from the small up and down statistical variations. The true indication of

> predictability is the standard deviation of the slope of the regression of

> lung cancer on smoking prevalence which is very small percentage-wise

> 

>  Cohen's

> > derived LNTT formula does not have the ability to adjust

> > for non-linear covariates like the BEIR VI formula

> > does.

> 

> 	--Wrong, wrong, wrong. My treatments of confounding factors do not

> depend on linearity. My treatment was based on BEIR-IV as it was the

> latest thing available. I could do a treatment based on BEIR-VI if it

> would be publishable, but I doubt if it would be considered new enough to

> be published

> 

> 

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