### GIGAMIND

Folder:
113 Math
File:
113.020.020.30 Survival analysis - Pros and cons

# Survival Analysis - Pros and Cons

## Bottom-line:

• Kaplan-Meier is simple, but overly simple and doesn't work well for estimation b/c it is non-parametric and you can't easily estimate numbers that in-between times.
• Weibull is an exponential model which has a hazard that can increase proportionally as time (t) progresses, which is not always realistic
• Proportional Hazards is most accurate b/c the Hazard can fluctuate as Time goes on, but it's also the most complicated and you can't estimate the survival function.

# Models

## Kaplan Meier

• Pros
• Simple
• You can estimate the survival
• Cons
• No functional form - no simple mathematical function that describes it
• Can not estimate the hazard ratio
• Can only include a few categorical `x`'s

## Exponential

• Pros
• Can estimate `S(t)` and HR
• Cons
• Not always realistic
• Weibull (parametric) allows HAZ to increase/decrease proportionally with time, but this isn't realistic all the time either
• Assumes a constant hazard, which is bad. E.g.
• as humans our risk of dying increases as we get older
• as babies we have a low risk, then higher risk as teens (risky behavior), then lower again at 30-40, then higher again as we go >60-70

• Me