summary versus individual data

["Harry Hinks" <harryhinks@hotmail.com>]

Prof. Cohen wrote -

	--Of course you have to collect enough data to get a true average, and 3 
houses is not enough. But aside from this, in your example, if LNT is 
correct, the only thing important for determining the number of cancers is 
the 9 pCi/L average. No further useful information is obtained by using 
measurements in particular houses.


---------But the important point is that my test has been done, and LNT
-fails, unless someone can come up with an alternative explanation. Failing 
one experimental test is enough to validate a theory. Of course other tests 
are always welcome.



---------------
That is my point - how do you know the 9 pCuries/liter is correct?

How many houses are enough?  How do you determine how many houses in a 
specific area need to be sampled to provide a representative sampling?  
Wouldn't it depend on the variance of radon concentrations in a specific 
area?  This is not like the atomic bomb data where there is decreasing 
exposure with distance that is somewhat predictable.  I just looked at one 
of your papers, it looks like you only have a few measurements representing 
an area with a population of 30,000 people or more in many cases.  Do you 
truly feel your limited number of measurements give you a true concentration 
(exposure) average?  In consideration of what Ruth said, how can these 
limited number of measurements for a given area be considered dose 
estimates?  How can you apply collective dose assumptions to concentration 
data generated from a few radon measurements obtained for a particular area. 
  I don't think the point is how many total measurements you have for the 
states, but rather how representative are the limited meausurements in a 
certain area.

If you do not think individual level measurements are needed, how well can 
you predict what the radon concentrations are in Radsafe subscribers houses? 
  We can actually test this.  If 20 radsafers (more if you like) can send me 
their radon concentrations (should we say living room) and zip code, I can 
collect the data and put it in a table.  I will send you the zip codes and 
we can look at the agreement between the actual measurements and your 
predictions.  Are you willing to do this?


Also, are you saying that because no one can explain what you find, the LNT 
fails?  I asked a professor I have in class about this and they told me that 
you could not test for cross-level bias in summary data studies.  So how do 
you know your study does not suffer from cross-level bias? This goes back to 
the ability to correct for confounding information with summary data.  My 
possible explanation for your findings is that they suffer from cross-level 
bias.  Can you show us that your studies do not suffer from cross-level 
bias?

Harry
harryhinks@hotmail.com

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