Box 9.2.a: Calculation of risk ratio (RR), odds ratio (OR) and risk difference (RD) from a 2×2 table
The results of a clinical trial can be displayed as a 2×2 table:
where S_{E,} S_{C,} F_{E} and F_{C} are the numbers of participants with each outcome (‘S’ or ‘F’) in each group (‘E’ or ‘C’). The following summary statistics can be calculated: |