Re: Cohen's ecologic study questions

["Field, R. William" <bill-field@UIOWA.EDU>]

Dr. Cohen,


We have given you many specific examples.  


For example, we have previously stated that you are performing your

stratifications based on confounders at the individual level, not the

group level.  Use aggregate level confounders for stratification if

you want to improve your ecologic studies.


Regards, Bill Field


R. William Field, M.S,

Ph.D.

College of Public Health

Research Scientist - Department of Epidemiology

Adjunct Professor - Department of Occupational and Environmental

Health

Graduate Faculty - College of Public Health 

N222 Oakdale Hall

University of Iowa

Iowa City, Iowa  52242


319-335-4413 (phone)

319-335-4748 (fax)

mailto:bill-field@uiowa.edu



At 12:48 PM 01/22/2002 -0500, BERNARD L COHEN wrote:

> 2) They continue to say that cross-level bias and inter county variability
> caused your findings.  Do you really have the data to show this is not the
> case?

        --I need a specific example -- see above. If a specific example is
offered, it is up to me to supply the data required.

> My most important question about the Field and Smith paper:  Are adjustments
> made using aggregate data (smoking, education, etc.)usually used to adjust
> for confounding at the individual level - sufficient for use in adjusting at
> the county level?

        --I do not "adjust" my data for anything. I treat confounding by
my method of stratification which is very much superior.

>  From reading their papers they say you may never find
> your answer because your data are lacking.  Can you really say you have
> tested all the possibilities if you do not have the data you need to adjust
> for aggregate confounding?

        --Providing the data is my problem. What I need is a
specific suggestion for which data are needed.

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