Basic Concept


Survival time

Generally it refers to the time elapsed from the start of a certain

Starting event to the end of an event. The unit of measurement can be year, month, day, hour, etc., as indicated by the common symbol t.

Censored data

It refers to the data that failed to obtain the exact time of survival of the study individuals for some reasons during the research, such as individuals who died in the middle of an accident, and survived after the test time expired.

Survival probability

The probability that an individual in the subject will still survive the beginning to the end of a unit time.

Survival function

Also named the survival curve, it is mainly used to describe the probability distribution of the object failure time and it is a monotonous non-increasing function.

Dangerous function

Also named the risk function, it refers to the probability of instantaneous death of an individual surviving at a certain moment during the survival analysis.