Which statement is an explicit advantage of the Kaplan-Meier estimator over actuarial life tables?

• A. It avoids the assumption that withdrawals occurred uniformly throughout the interval
• B. It assumes withdrawals occur uniformly within intervals
• C. It cannot handle censored observations
• D. It requires a constant hazard over time

Answer: (A)

Kaplan-Meier is a nonparametric way to estimate the survival function that uses the exact times of events and properly accounts for censored observations. Its explicit advantage over actuarial life tables is that it does not rely on the assumption that withdrawals (events) are uniformly distributed within each interval. By updating the survival probability only at observed event times and using the number at risk just before each event, Kaplan-Meier provides a stepwise estimate that can adapt to how events actually occur, rather than smoothing them uniformly across intervals. Actuarial life tables often impose that uniform-within-interval assumption, which can bias estimates if withdrawals cluster at certain times. In addition, Kaplan-Meier handles censoring naturally and does not require a constant hazard over time, so those aspects are not the specific advantage in question.