ABSTRACT
This chapter describes survival concepts for a single outcome or event type and discusses absolute risk in the presence of competing risks. An important issue in survival analysis is the choice of time scale. In clinical studies a natural choice may be time-on-study, namely the time since a particular event that marks the beginning of study observation. For example, one may be interested in the time from diagnosis and treatment of breast cancer to a subsequent event, such as breast cancer recurrence or death from breast cancer. In cohort studies of disease etiology or incidence, subjects without a given disease are followed up to detect the time of occurrence of that disease. The Kaplan-Meier or product limit estimator is the limit of the life-table estimator when intervals are so small that at most one distinct failure time occurs within an interval.
