RE: Cohen's Ecologic Studies

[EPIRAD@mchsi.com]

Marco,



Dr. Lubin is a statistician at the National Cancer 

Institute. The abstract is more understandable after 

reading the paper.  I am sure Dr. Lubin's abstract was 

not meant to confuse anyone.  If you have specific 

questions about the abstract, I would suggest you get a 

copy of the paper first, and then direct further 

questions directly to him. 



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. As for Dr. Cohen's 

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

the lung cancer mortality with his smoking data. Cohen's 

derived LNTT formula does not have the ability to adjust 

for non-linear covariates like the BEIR VI formula 

does.  Therefore, there remains substantial residual 

confounding from smoking and other factors. Some of the 

confounding factors may not even be confounders at the 

individual level, but only at the ecologic level.  For 

an example, please read Dr. Lubin's paper.   



Bill Field

http://myprofile.cos.com/Fieldrw



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