Cohen's ecologic study questions

["Rad health" <healthrad@HOTMAIL.COM>]

Don Smith previously wrote:



Drs. Field and Smith have repeatedly "specifically suggested" in their Forum 

paper and follow-up papers in Health Physics that one of the major factors, 

among others, most likely causing your paradoxical findings is cross-level 

bias or inter county variability.



Dr. Cohen previously wrote:



If you will raise specific issues in their last letter, I will respond on 

RADSAFE.



I have shown that cross level bias could have caused my discrepancy with LNT 

with specific examples, but these examples were completely implausible.



---------------------------------------

Dr. Cohen, I have specific questions concerning Field's, Smith's, and 

Lynch's paper for you.



I think one of their focuses has been on the quality of your data.  They 

previously suggested that you could improve your data by using lung cancer 

INCIDENCE data from the SEER states.



Specific issues:



1) Smith and Field showed that by using SEER data in Iowa your large inverse 

association disappeared. Have you ever explained in specific scientific 

terms why the association went away when SEER data was used?  Have you 

recalculated your rates for just the SEER states using SEER data as they 

previously suggested? The SEER states are listed here:  

http://seer.cancer.gov/



2) They continue to say that cross-level bias and inter county variability 

caused your findings.  Do you really have the data to show this is not the 

case?



My most important question about the Field and Smith paper:  Are adjustments 

made using aggregate data (smoking, education, etc.)usually used to adjust 

for confounding at the individual level - sufficient for use in adjusting at 

the county level?  From reading their papers they say you may never find 

your answer because your data are lacking.  Can you really say you have 

tested all the possibilities if you do not have the data you need to adjust 

for aggregate confounding?



I like you just have an interest in explaining your findings.



Don Smith



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