Introductory text
Box 9.2.a: Calculation of risk ratio (RR), odds ratio (OR) and risk difference (RD) from a 2ยด2 table
9.2.2.1 Risk and odds
9.2.2.2 Measures of relative effect: the risk ratio and odds ratio
9.2.2.3 Warning: OR and RR are not the same
9.2.2.4 Measures of absolute effect: the risk difference
9.2.2.5 What is the event?