Survival curve (time-to-event curve) plotting the estimated proportion of subjects that have not yet had an outcome of interest (eg, death) as a function of time. Every time a subject dies (or has the event occur), the curve steps downward. The proportion of individuals alive (or event-free) and not censored at a given time yields an estimate of the probability of survival to that time. The time at which 50% of subjects have died is the median survival time.
Courtesy of Dr. Donald Noah.