The Kaplan-Meier curve is a statistical tool used to estimate the survival function from lifetime data. It provides a visual representation of the probability of survival over time, allowing researchers to analyze the time until an event occurs, such as death or disease recurrence. The curve is particularly useful in clinical studies to compare the survival rates of different groups. The curve is constructed by plotting the proportion of subjects who survive at each time point, taking into account censored data, which refers to individuals who leave the study or are lost to follow-up. This method helps in understanding the effectiveness of treatments and the impact of various factors on survival.