Noisetosignal ratio^{a}

Proportion of results where RR_{EDW} p >0.05 (%)

RR_{
ED
}_{
W
} (adjusted for confounder W)


Average

95 % Confidence Interval


0.10

100

0.99

0.97–1.01

0.25

100

0.98

0.96–1.00

0.50

91

0.96

0.94–0.98

0.55^{b}

78

0.95

0.94–0.97

0.60

56

0.95

0.93–0.97

1.0

0

0.91

0.90–0.92

10^{c}

0

0.83

0.83–0.83

 ^{a}ratio of variance of measurement error relative to variance of confounder
 ^{b}in practice, it is not possible to have such precise knowledge about the extent of measurement error, so any calculation of this sort is necessarily approximate and is meant as a guideline for selection of suitable method to measure a confounder, but we can say that error variance should be closer to 0.5 than to 0.6
 ^{c}empirically determined to correspond to error in confounder hypothesized to exist in the data (F_{
obs
}) and resulting in failure to control cofounding effect of RR_{EDFobs} = 0.83 for exposure to mercury