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Table 1 Individual vs. ecologic data

From: Bias magnification in ecologic studies: a methodological investigation

 

Individual (interior cells)

Ecologic (margins)

 

exposed

unexposed

sum

exposed

unexposed

sum

cases

16

12

28

?

?

28

noncases

24

48

72

?

?

72

total

40

60

100

40

60

100

risks

0.4

0.2

 

X

0.40

 

RD

0.2

  

Y

0.28

 
    

n

100

 
  1. Individual-level information on exposure and outcome are shown by the interior of a two-by-two table; they are summarized by the risks in the unexposed and exposed and the risk difference (RD). Ecologic studies possess only the margins of the table, summarized by the average exposure X, average risk Y and group size n.
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Environmental Health

ISSN: 1476-069X