This is an archived version. For the current version, please go to training.cochrane.org/handbook/current.

If it is possible to extract the total number of events in each group, and the total amount of person-time at risk in each group, then count data can be analysed as rates (see Chapter 9, Section 9.4.8). Note that the total number of participants is not required for an analysis of rate data but should be recorded as part of the description of the study.