Editing Survival analysis (section)

===Definitions of common terms in survival analysis===

The following terms are commonly used in survival analyses:

*Event: Death, disease occurrence, disease recurrence, recovery, or other experience of interest
*Time: The time from the beginning of an observation period (such as surgery or beginning treatment) to (i) an event, or (ii) end of the study, or (iii) loss of contact or withdrawal from the study.
*Censoring / Censored observation: Censoring occurs when we have some information about individual survival time, but we do not know the survival time exactly. The subject is censored in the sense that nothing is observed or known about that subject after the time of censoring. A censored subject may or may not have an event after the end of observation time.
*[[Survival function]] S(t): The probability that a subject survives longer than time t.