Re: Threshold (was RE: Healthy Worker Effect vs. Hormesis)

[Bernard L Cohen <blc+@pitt.edu>]

The principle you refer to is probably derived from physics. In quantum 
physics, things that are not observable in principle are not meaningful. 
But the key words here are "in principle" as opposed to in "practice". In 
principle, the effects of even the lowest level radiation could be 
observed by having enough people under perfect control for a long enough 
time period. The fact that this would be impractical is irrelevant.

Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu


On Mon, 25 Mar 1996, Albert Lee Vest wrote:

> Joe Shonka (sra@crl.com) says
> 
> >>Al (Tschaeche),
> >I can't believe you.  But, you've got the controversy stirring.  In
> >order to prove a statistical point, the power of the study must be
> >defined.  In many cases, the statement has been made that it would
> >take a controlled experiment with more than the world's population to
> >establish the "linear with no threshold" theory with adequate power
> >at occupational dose levels.  The converse is also certainly true. 
> 
> Something I've wondered about.  Even by the largest possible (finite) study,
> even assuming the single-parameter "LNT" dose-effect model, it can be shown
> that health effects below a certain (finite) exposure level cannot be
> detected.  Is that level then not in effect a threshold?
> 
> The principle appealed to is this:  For anything to be said to exist, one
> must be able, in principle, to detect it.  Since effects below that
> calculated level (whatever it is) can never be found, then it is reasonable
> to conclude they don't exist.
> 
> Comments?  Is the principle above generally accepted?
> 
> Albert Lee Vest           The Ohio State University
> Health Physicist    Room 103 1314 Kinnear Road Bldg
> (614)292-1284                     1314 Kinnear Road
> avest@magnus.acs.ohio-state.edu   Columbus OH 43212
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