Re: Cohen's ecological data: a test of LNT?

[William V Lipton <liptonw@dteenergy.com>]

Can we bury this dead horse?

The opinions expressed are strictly mine.
It's not about dose, it's about trust.

Bill Lipton
liptonw@dteenergy.com

Bernard L Cohen wrote:

> On Fri, 17 Mar 2000, Ken Mossman wrote:
>
> > This my last shot!
> >
> > Cohen and I agree that LNT is a causal relationship. Howevever, I am now
> > totally confused about whether Cohen's data tests for a causal relationship.
> > In his April 1997 paper in Health Physics (page 625), Cohen indicates that
> > his data do not test for a causal relationship but has a much more limited
> > objective. Now Cohen says that his data tests for a causal relationship.
> > Which is  it? Either the data test for a causal relationship or thery don't!
>
>         --It tests for one particular type of causal relationship, namely
> Linear-no threshold (LNT). There are many other types of causal
> relationships --quadratic, threshold, etc -- and my data do not test for
> them or distinguish between them.
>         The quote from the page 625 reference above is: "case-control
> studies investigate the causal relationship between radon exposure and
> lung cancer, whereas our work has the much more limited objective of
> testing the linear-no threshold theory". The word "investigate" means
> to me "trying to determine". Our work does not, and cannot do this. There
> is no implication in my statement that LNT is not a particular type of
> causal relationship.
>
> >
> > If the data test for a causal relationship, as Cohen now states, then the
> > ecological fallacy becomes operative. If the data do not test for a causal
> > relationbship, then the data are not a test of LNT because LNT is a causal
> > relationship (as Cohen and I now agree).
>
>         --My data test for the one particular type of causal
> relationship,namely LNT, for which the "ecological fallacy does not apply.
> If I were to go further and "investigate" what type of causal relationship
> is operative, the ecological fallacy would apply, so I cannot do that. I
> can only show that LNT does not apply.
>
> >
> Bernard L. Cohen
> Physics Dept.
> University of Pittsburgh
> Pittsburgh, PA 15260
> Tel: (412)624-9245
> Fax: (412)624-9163
> e-mail: blc+@pitt.edu
>
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