Re: TRAB and back to Re: Lung cancer mortality from radon versus....

[Michael Ford <michaelford@cox-internet.com>]

It's been a real pleasure, Don.



on 1/24/02 3:10 PM, Rad health at healthrad@HOTMAIL.COM wrote:



> 

> Michael,

> 

> Dr. Field's reply sounds like the same thing I had stated previously.

> 

> Try putting 15% of the subjects in the upper exposure group and then you

> break the remainder up evenly, what WLM categories do you get?



How do you do that on an a priori basis and with analyzing the data?  If

it's done a priori, you establish intervals without considering the data.

If you intentionally place a specific number of cases into an exposure

category, there's nothing a priori about that.  Again, why 16.95 and why

4.23 WLM?  And how can you possibly claim that precision given the

uncertainties of the data that's being used  (specifically, human recall).



> 

> They found statistical significance when all subjects were included and when

> the subset analysis only included lung cancer patients that were alive at

> time of interview.  No one who died was excluded.



130 cases were excluded in the alive analysis.  Table 4, page 1098.  Is

p=0.14 what you call statistically significant?



> 

> I congratulate Dr. Field and the other investigators on the study for their

> landmark study and excellent detailed retrospective assessment of radon

> exposure.  I see Dr. Field worked as a health physicist and a co-author was

> Dr. Steck a nuclear physicist (and both members of the HPS since the early

> 1980s), unlike the miner studies it looks like they incorporated much of

> their past health physics experience into that study including publishing an

> entire paper just on QA for the study.

>

> I would also urge Dr. Cohen to follow the well thought out suggestions by

> Dr. Field for improving his ecologic analyses.

> 

> Respectfully, Don Smith

> 

> _________________________________________________________________

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> 



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