Survival Analysis

Survival Analysis is a branch of statistics for analyzing the expected duration of time until one or more events happen, such as death in biological organisms and failure in mechanical systems.

Core Concepts

• Time-to-Event: The duration from a defined starting point (e.g., surgery) to the event of interest (e.g., recurrence).
• Censoring: Occurs when we don't know the exact survival time of a subject (e.g., study ends, patient lost to follow-up). Survival analysis specifically handles this data instead of discarding it.
• Hazard Function: The instantaneous rate of occurrence of the event.

Choose Your Analysis Method

1. Kaplan-Meier Analysis →

Non-parametric method used to estimate the survival function from lifetime data. Best for visualizing survival curves and comparing two groups (Log-rank test).

2. Cox Proportional Hazards Regression →

Semi-parametric method used to investigate the effect of several variables (covariates) on the time a specified event takes to happen.