Re: ?Ecological Fallacy

[John Goldsmith <gjohn@bgumail.bgu.ac.il>]

The choice of iodine and goiter as an example of ecological fallacy  is
especially interesting since not only do we actually have a great deal of 
individual data on iodine exposure and size of the thyroid gland, we also 
have abundant evidence that treatment with iodine will reduce the size of 
the gland and addition of iodized salt in an area will prevent onset of 
goiter.  
	Citing opinions on radon exposures one study at a time is not a 
very effective way to approximate the truth of relationships.  Epidemiology
must deal with the perennial problem of incomplete sets of relevant 
variables, which in the case of studies of lung cancer must include smoking
histories and the exposures of populations many years ago.  Since it has 
been shown that Radon daughters (the active agents in lung cancer) adhere to 
glass surfaces and past radon exposures can be estimated by counts of glass 
panes or mirrors, why don't some of the Health Physicists try to fill the gap 
in our knowledge of previous exposures using these methods?
	John R. Goldsmith, M.D. Professor of Epidemiology  

On Thu, 10 Aug 1995 gr_cicotte@ccmail.pnl.gov wrote:

>           That's an interesting analogy, but it doesn't fully apply, in my 
>           opinion.  The issue as stated, while it provides an indication 
>           that further study would be indicated, and may even be enough 
>           for the development of a theory, does not contain proof that the 
>           lack of iodine is the causal factor.  We happen to know it is, 
>           but we know because we've done experiments to determine the 
>           facts, rather than depending on just the effect and a single 
>           common factor among multiple possibilities.
>           
>           V/R
>           George R. Cicotte
>           Research Engineer
>           HEALTH PROTECTION DEPARTMENT
>           Battelle Pacific Northwest Laboratories
> 
> 
> ______________________________ Reply Separator _________________________________
> Subject: ?Ecological Fallacy
> Author:  HWADE@aol.com at -SMTPlink
> Date:    8/10/95 5:53 AM
> 
> 
> Daniel Strom, Ph.D., states that Cohen's work is subject to the "ecologic 
> fallacy", because it meets this definition, which he quotes:
> >The ecologic fallacy is "An error in interpreting associations >between 
> ecologic indices.  It is committed by mistakenly >assuming that, because the 
> majority of a group has a >characteristic, the characteristic is related to a 
> health state >common in the group" (Slome C, Brogan DR, Eyres SJ, Lednar >W.
>  Basic Epidemiological Methods and Biostatistics - A >Workbook. Boston: Jones
> and Bartless, 1986, Chapter 9 & p. >306).
>           
> I suppose another example of the ecologic fallacy is the relation between 
> iodine and goiter.
>           
> We all know that living in an area with a lack of iodine in soil (majority of 
> a group has this characteristic) causes an greater incidence of goiter ( a 
> health state common to the group).
>