Kaplan-Meier analysis is largely used in nephrology to estimate a population survival curve from a sample. If patients are followed-up until death, the survival curve can be estimated simply by computing the fraction survival at each time point. Kaplan-Meier analysis allows the estimation of survival over time, even when patients drop out or are studied for different lengths of time. In Kaplan-Meier analysis, the comparison between two survival curves is made by the log-rank test.