ABSTRACT
The product-limit (PL) estimator, developed by Kaplan and Meier, estimates the survival function, S, using right-censored data. It has a similar definition to the actuarial estimator, except that the interval endpoints are no longer fixed; the intervals comprise the spaces between the data as they are observed. Some of the data may be censored and some of the data may be uncensored. The chapter examines the hand calculation, software calculation and graphical calculation of the PL-estimator of the survival function. The heavy censoring pattern especially at the top of the distribution, makes long-term survival prospects difficult to ascertain without the assistance of the PL-estimator. Consider a set of observed right-censored survival data plotted along a time axis, using different notations to differentiate between the censored data points and the uncensored data points. The diagram uses a standard notation for this representation: hollow dots for right-censored observations; filled-in dots for uncensored observations.
