Cohen's erroneous statements

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

BERNARD L COHEN wrote on Fri, 11 Jan 2002 09:40:36 -0500 (EST)wrote:



BC  Note that your suggestion would also affect every other study that

has ever been done on radon vs lung cancer, including all the case-control 

studies.



Dr. Cohen's statement is incorrect - The MO study used glass-based detectors 

which can estimate past radon progeny exposure. Further- the Iowa study used 

HRD detectors which can examine the degree of progeny attachment and 

retrospective radon progeny exposure.



BC Are you suggesting that a treatment is needed for non-smokers

living in houses where there are smokers? That would be very difficult in 

any study. In case-control studies, they don't ask whether there are other 

people in the house who smoked.



Again Dr. Cohen's statement is absolutely false. Most of the case-control 

studies collect this information including the IA and MO studies.



BC  That would be fine with me but they should be problems that do

not apply to case-control studies. Also, I could not respond to 20-30

mechanisms, so I would much prefer if you could specify a few that are

most important in your list.



Cross level bias as well as many other factors affect the interpretability 

of the ecologic approach, but not the case-control approach.  For example, 

Cross-level bias does not apply to case-control studies.



Ecologic studies are useful for generating hypotheses.  Dr. Cohen has his 

hypothesis based on the findings of his ecologic study.  Most people at this 

point would move on to a more rigorous epidemiologic approach to test their 

hypothesis, namely a case-control study or prospective cohort study.



Dr. Field offered to write a paper with Dr. Cohen over a year ago to examine 

the strengths and limitations of the ecologic approach versus the 

case-control approach in evaluating the risk posed by residential radon 

exposure.  Dr. Cohen declined (check the archives).  Dr. Cohen should be 

able to support the validity of his findings without relying on saying this 

is how case-control studies do it. In other words let your study stand or 

fall on its own merits.



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