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

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

On Wed, 15 Mar 2000, Ken Mossman wrote:

> Cohen states  that "LNT is a special case of a causal relationship." I do
> not understand this statement. There is no "special case." LNT IS
> unconditionally a causal relationship. It is no more or no less a causal
> relationship than a curvilinear dose-response, or threshold dose-response,
> etc. 

	--LNT is a causal relationship, but there are other types of
causal relationship -- curvilinear, etc. Thus, LNT is a "special case" of
a causal relationship, as that term is ordinarily used.

>  
> My logic is quite simple and straight forward:
> 
> 1.	LNT is a causal relationship.
> 2.	Cohen's data does not test for a causal relationship (in order to
> avoid the ecological fallacy).
> 3.	Therefore, Cohen's data does not test LNT. 

	--1. Should be "LNT is one type of causal relationship"
	--2. Should be "Cohen's data does not test all possible types of
causal relationship"
	--3. Should be "Cohen's data tests only one type of causal
relationship, namely LNT. It does not test any of the other types"

> 
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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