Statistical methods in epidemiology. IX. Survival (failure-time) models.
OBJECTIVE
This article introduces readers to survival (failure-time) models, with a focus on Kaplan-Meier curves, Cox regression and sample size estimation.


METHODS
An example is used to show readers how to calculate a Kaplan-Meier curve from first principles.


RESULTS
What makes survival data unique is censoring. Readers should understand censoring before undertaking an analysis of survival data.


CONCLUSIONS
The Cox model continues to set the standard for survival models, and will continue well into the future.
Rigby
Alan S
AS
Academic Cardiology, University of Hull, and Hull York Medical School, Kingston-upon-Hull, UK. asr1960@hotmail.com
Zhang
Jufen
J
Goode
Kevin M
KM
D004812:Epidemiologic Methods; D006801:Humans; D015233:Models, Statistical; D016016:Proportional Hazards Models; D018401:Sample Size; D016019:Survival Analysis