Quantitative Methods 2017

Excess Risk

Develop Disease

Doesn’t

Exposed

a

b

Unexposed

c

d

 Excess Absolute Risk: difference in risk between exposed and unexposed (control) populations

Excess Absolute Risk = a / (a+b) - c / (c + d)

 Excess Relative Risk: proportion of Relative Risk (RR) due to exposure

a / (a+b) - c / (c + d)

Excess Relative Risk = Relative Risk -1 =

c / (c+d)

FMB