Advertisement
Published in:
2017 | OriginalPaper | Chapter
4. Simple Frailty Models
Authors : Il Do Ha, Jong-Hyeon Jeong, Youngjo Lee
Published in: Statistical Modelling of Survival Data with Random Effects
Publisher: Springer Singapore
Activate our intelligent search to find suitable subject content or patents.
Select sections of text to find matching patents with Artificial Intelligence. powered by
Select sections of text to find additional relevant content using AI-assisted search. powered by
Abstract
The concept of frailty was first introduced by Vaupel et al. (1979) (Demography 16:439–454, 1979) to account for the impact of individual heterogeneity in univariate (independent) survival data. In this chapter, we introduce the frailty model, an extension of the Cox PH model, for analyzing correlated survival data. The frailty is modeled by an unobserved random effect acting multiplicatively on the individual hazard rate to describe the individual heterogeneity and the correlation (dependency) among survival data from the same subject or cluster (Clayton 1978 (Clayton DG in Biometrika 65:141–151, 1978); Hougaard 2000 (Hougaard P in Analysis of multivariate survival data. Springer, New York, 2000); Duchateau and Janssen 2008 (Duchateau L, Janssen P in The frailty model. Springer, New York, 2008)). Even if heterogeneity and correlation are different concepts, they can both be modeled by frailties.