Kaplan-Meier estimation of the survival function

When analyzing the time to the AE, we need an analytic way to deal with these censored observations. Although we do not know what would have happened for these participants, we do know that they were at risk for some period of time and survived their time in the study without experiencing the AE. Accordingly, the main objective of this analysis is to describe how long participants survive without experiencing the event. 

The name survival analysis reflects one situation in which this type of analysis is used. When the participants in a clinical trial are very ill, the measurement of efficacy can be the length of time that they live, that is, death is the event.  

Chapter 8 Confirmatory clinical trials Safety data I 

The last day the participant was at risk for reporting the AE without having done so. This type of participant is labeled parenthetically as censored.  

This also leaves eight participants at risk on day 3. On day 3 no participant repotted the event. Of the eight participants who were at risk on day 4, one reported the AE and one dropped out (that is, was censored from the analysis). As before, the probability of an AE occurring is 

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The Kaplan-Meier estimate of the survival function at time t is ... 

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