Kaplan-Meier Survival Analyzer

Survival Analysis Fundamentals

Survival analysis studies the time until an event of interest occurs. Unlike standard statistical methods, it handles censoring — the incomplete observation of event times.

Key concepts: • Survival function S(t): Probability of surviving beyond time t • Hazard function h(t): Instantaneous event rate at time t, given survival to t • Censoring: Right-censoring (most common) occurs when follow-up ends before the event • At-risk set: Subjects still being observed at each time point

Clinical and Preclinical Applications

Kaplan-Meier analysis is used in:

• Clinical trials: Primary endpoint for overall survival, progression-free survival, disease-free survival • Preclinical studies: Tumor growth delay, time-to-event in animal models • Device reliability: Time-to-failure analysis for medical devices • Behavioral research: Latency to first response, time to criterion performance

The log-rank test is the standard method for comparing treatment vs. control survival curves in randomized trials.