AW: [ RadSafe ] Excess relative risk
Bernard L. Cohen
blc+ at pitt.edu
Wed Feb 13 10:13:59 CST 2008
John Jacobus wrote:
> Dr. Cohen,
> So how should we view your often quoted epidemiologica studies? I
> have read your papers a number of times and am impressed with your
> work. Nevertheless, not being an epidemilogist, I would really like
> to know how did you treat all the confounding factors in your studies
> if not by regression analysis? that if you think regression analysis
> is risky what other methods are there?
My treatment of confounding factors is described and justified in
great detail in my paper in Dose-Respoinse 3: 369-390; 2005. I teat
them by what I call "stratification" and in that paper, I show that it
has important advantages over multiple regression analysis. I did not
mean to demean multiple regression analysis, but I must say I am
uncomfortable in the way some epidemiologists use it to say they have
"adjusted for" confounding with an attitude that it is an "air-tight"
procedure for adjusting, leaving no room for questioning or
uncertainty.I think they should recognize that it is an imperfect
> As a reader of history, I think that quantum mechanics and relativity
> would have been formulated within the Twenty Century. While Lord
> Kelvin may have prounced that there was nothing to discover in
> physics, it was obvious that the Planck's explanations of blackbody
> radiation in 1900 lead to Einstein's paper on the photoelectric effect
> in 1905. There was a problem that needed to be solved. It is also
> clear that Lorentz was close to discovering special relativity. If
> not him, then certainly someone else.
> */"Bernard L. Cohen" <blc+ at pitt.edu>/* wrote:
> I hope this does not sound too radical: In my experience,
> epidemiologists are not *scientists* in the broad sense of that term.
> They practice a *technology* which has been "boxed" and they are not
> willing to think outside that box. For any new ideas or
> approaches, it
> is "their way or the highway"; they reject them with only the
> reasoning, or more commonly ignore them. That is not the way
> have traditionally operated. If physicists operated that way, we
> never have had quantum theory, relativity, or any of the many great
> advances of 20th century physics.
> Their box has been successful in many applications, but it is prone
> to failure where statistics are marginal or where there can be
> confounding factors. They customarily treat the latter with multiple
> regression analysis which is fraught with dangers -- they call this
> "adjusting for confounding factors", factors they select with
> less than air-tight reasoning.
> If 2 or 3 epidemiologists take a position, a "consensus" forms
> without those who constitute the consensus spending any time or
> on the subject. They just don't like to think outside their box. They
> seem to have no experience in doing that.
> John Jacobus wrote:
> > One of the purposes of a skeptic is not so much to challenge as
> to present what is unknown.
> > I have been accussed of being silent. I am not an
> epidemiologist, so I have to relie on those who are recognized
> experts. (If you choose to ignore the conclusion of experts, that
> is your choice.) The consensus has been that there are no
> demonstracted effects below 100 mSv. Neither harmful or
> beneficial. All studies are individual pieces of a puzzle. To
> date, the well-known epidemiologists have reached the conclusion
> stated above. Individual studies may support your position or
> mine, but the concensus has always remained the same.
> > Your uncited comments below are interesting, but how do they fit
> in the overall study of radiation effects? I have seen some
> studies that do show negative slopes. We can all cherry pick the
> data that supports our positions, but what do the experts say?
> > Rainer.Facius at dlr.de wrote:
> > "Of course, there is no proof of negative excess risk."
> "If history teaches any lesson it is that no nation has an inherent
> right to greatness. Greatness has to be earned and continually re-earned."
> - Norman Augustine, Chairman of the National Academies Committee
> -- John
> John Jacobus, MS
> Certified Health Physicist
> e-mail: crispy_bird at yahoo.com
> Never miss a thing. Make Yahoo your homepage.
Bernard L. Cohen
Physics Dept., University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245 Fax: (412)624-9163
e-mail: blc at pitt.edu web site: http://www.phyast.pitt.edu/~blc
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