Which statement about life-table methods is false?

• A. They group events into intervals to estimate interval survival probabilities.
• B. They produce cumulative survival probabilities only at the end of each calendar year.
• C. They require detailed event times for all individuals.
• D. They are used to estimate survival probabilities at specific event times without intervals.

Answer: (D)

Life-table methods summarize survival by grouping follow-up time into predefined intervals and estimating the probability of surviving each interval, then combining those interval probabilities to obtain the overall survival up to any time point. This approach relies on counts within each interval—how many events occurred and how many were at risk at the start—rather than exact event times for every individual. As a result, you typically obtain survival estimates for the end of each interval (or for the interval’s boundaries) rather than at precise, individual event times.

The statement that life-table methods are used to estimate survival probabilities at specific event times without intervals is not correct because, by design, they rely on interval-based information and provide interval-end survival probabilities. If you need survival probabilities at exact event times, you would use a method that incorporates the precise event times, such as the Kaplan–Meier estimator.