Re: Pooled studies and their increased sensitivity--is it real? (was Euzropean radon study)

[Maury Siskel <maurysis@ev1.net>]

Hi Richard,

Meta-studies are fraught with design and analysis problems. You are wise 

to exercise great skepticism -- they often are not nearly so 

straightforward as their advocates wish..

Cheers,

Maury&Dog       maurysis@ev1.net



============

Richard L. Hess wrote:



>

> Franz Schoenhofer kindly pointed us to the following study: 

> http://bmj.bmjjournals.com/cgi/content/abstract/bmj.38308.477650.63v1

>

> This time, for radon, it's a summary of data from multiple other studies.

>

> Previously, I had been pointed to a study of power lines in the 

> British Journal of Cancer:

> http://www.powerlinefacts.com/British%20Journal%20of%20Cancer%20Abstract%20of%20Meta-Analysis%20of%20Cancer.htm 

> (forgive the website that has the link, but it was easier to find, and 

> I don't think the study is adulterated there.)

>

> My question is, it seems that while individual studies don't seem to 

> identify harmful effects with any statistical certainty, the larger 

> base of a pooled study appears to show harmful effects.

>

> But, I'm wondering if these pooled studies also have the potential for 

> magnifying the effects in a way that perhaps over-states the overall 

> sensitivity to a stimulus.

>

> The reason I'm asking is that it seems that the majority of 

> "ill-effect" studies are pooled studies rather than individual ones.

>

> The discussion on arsenic caused me to chuckle in one regard: it is a 

> clear example of the dose making the poison, as arsenic is a favoured 

> method of doing people in -- at least in novels <smile>.

>

> Cheers,

> Richard 

>



************************************************************************

You are currently subscribed to the Radsafe mailing list. To

unsubscribe, send an e-mail to Majordomo@list.vanderbilt.edu  Put the

text "unsubscribe radsafe" (no quote marks) in the body of the e-mail,

with no subject line. You can view the Radsafe archives at

http://www.vanderbilt.edu/radsafe/