Analysis of dependent survival data applied to lifetimes of amalgam fillings.

When studying lifetimes of amalgam fillings, one is faced with the fact that each patient may contribute multiple survival data. This creates a dependence problem, and some methods for solving it are presented here. Analysis for individual patients with simple approaches for combining data is discussed first. Then a parametric frailty model is applied to analyse variation within and between patients. The results are presented in the form of an empirical Bayes estimate for each patient.