## 10.4 Time and censoring

time is the number of days from surgery until either the occurrence of the event (death) or the last time the patient was known to be alive. For instance, if a patient had surgery and was seen to be well in a clinic 30 days later, but there had been no contact since, then the patient’s status would be considered alive at 30 days. This patient is censored from the analysis at day 30, an important feature of time-to-event analyses.