Ecologic versus Case-Control Studies

["R. William Field" <bill-field@uiowa.edu>]

Jim Muckerheide made the statement that the "power of the statistics of
even a small ecological study is much more powerful than any human case
control study"  

Jim,  

1. What is your definition of power of a study?  

2. In your opinion do you see any differences between the "power of the
statistics" and the "power of the study".

2.  Are you really saying ecologic studies have more power to detect an
association (or lack of one) than case-control studies?   

3.  You asked, What is Dr. Cohen's data suffering from?  Could his results
be suffering from cross level bias within his ecologic stratifications?  Is
this at all possible in your opinion?  If no, why not?

Bill Field
bill-field@uiowa.edu



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R. William Field, Ph.D.
Division of Epidemiology
Department of Preventive Medicine
  and Environmental Health
N222 Oakdale Hall
University of Iowa
Iowa City, Iowa 52242
319-335-4413 (phone)
319-335-4747 (fax)
mailto:bill-field@uiowa.edu
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