An additive frailty model for correlated life times.

A frailty model for multivariate correlated life times is considered. The model both extends, in a rather straight-forward way, ordinary survival analysis with its emphasis on hazard modeling and incorporates well-known variance components models to account for the dependence between events of related individuals. Different approaches to estimation and inference are considered. An example from an ongoing study of genetic and environmental influences on premature death in adults serves to motivate and illustrate the model. Multivariate frailty models offer a conceptually simple and promising framework for analysis of correlated event times data, even if current knowledge is too sparse for such models to be tested critically.