# Calculate Relative Risks to compare incidence in treatment groups versus a control

Check this option to compute the ratio of incidence in treatment groups versus a control group (for example, the relative risk of an adverse event).

A specific control value can be specified using the Treatment Control Level option. If that field is left blank, the default level is either Placebo or Pbo if this is found (case insensitive). Otherwise, it is the last sorted level. The relative risks for each treatment group are then reported in the output data table results along with an additional Treatment Only Occurrence Flag column that indicates whether a given event only occurred in (one of the) treatment group(s).

Note: If there was no occurrence of an event in the control or placebo group, the relative risk values will be missing since the comparison cannot be computed.

The computed column variables are shown in the results and can be used in the data filter (in the case of more than two treatment arm values, a maximum treatment relative risk value is available for filtering).

Note: If only one treatment group level is found, this option is ignored.