RE: "Are you a statistician?"

["Dukelow, James S Jr" <jim.dukelow@PNL.GOV>]

Jim Nelson wrote:

-----Original Message-----

From: Jim Nelson [mailto:nelsonjima@hotmail.com]

Sent: Thursday, December 06, 2001 1:23 PM

To: Dukelow, James S Jr; hflong@pacbell.net

Cc: radsafe@list.vanderbilt.edu

Subject: RE: Risks of low level radiation - New Scientist Article





Mr. Dukelow,



Are you a statistician?  Larger populations are good if you have good 

underlying data to describe the population.  Unfortuantely, it is very hard 

to derive good data from surrogate ecologic measurmements such as sales tax 

on cigarettes (used to infer smoking).



The other study I provided a link to did use data from individuals as Dr. 

King suggested.



As I told Dr. Cohen a few weeks ago, I agree with the papers by Smith et al. 

that describe the limitations of Dr. Cohen's work.  The smoking data he uses 

is so bad, it can only predict a little over 30% of the the lung cancers in 

the counties. If there was no confounding, it should be able to predict 85% 

or so.  I do not call that good control of confounding.



Jim



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



"Are you a statistician?"  Ah, the subtle appeal to authority.  I am as much of

a statistician as the average epidemiologist.  My education is in mathematics

and nuclear engineering, with an MA and ABD in Math and an MS in Nuclear

Engineering.  In my career in the nuclear business I have worked primarily as a

risk and safety analyst.  Risk analysis, of course, is essentially probabilistic

and statistical.  Before my mid-life crisis and switch to nuclear engineering, I

taught math full- and part-time in universities and colleges in the U.S. and

Venezuela.  Since 1986, I have been on the adjunct faculty in Computer Science

at the local campus of Washington State University -- and more recently adjunct

faculty in Mathematics, teaching on the order of 12-15 courses during that time

-- all of them mathematics, sometimes lightly disguised as computer science.  I

have taught Baby Statistics and upper division Probability and Statistics a

number of times.



That said, I consider myself a mathematician and engineer rather than a

statistician.  I know enough statistics to be dangerous to myself and others and

have, on various occasions, demonstrated both sides of that assertion.



I am familiar with Bill Field's Iowa radon study and with his criticisms of

Cohen's work and have discussed both with him.  I am unpersuaded.  For the

moment, I think we are agreeing to disagree.



You make an interesting assertion about Cohen's data that I cannot check

immediately, as I am in the process of unpacking my office from a recent carpet

replacement.  My strong impression/memory of his papers is that his control for

confounding is very strong, much more so than any of the papers Field's cites,

including his own.



Are you a statistician, Mr. Nelson?



Best regards.



Jim Dukelow

Pacific Northwest National Laboratory

Richland, WA

jim.dukelow@pnl.gov



These comments are mine and have not been reviewed and/or approved by my

management or by the U.S. Department of Energy.

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