ABSTRACT
Survival analysis is the phrase used to describe the analysis of times from some time origin until an end point marked by the occurrence of an event. If the end point is the death of an individual, the resulting data are literally survival times. However, data of a similar form can be obtained when the end point is not fatal, such as the relief of pain, and the methods described apply equally to these end points. Although this book focusses on biomedical applications, there are many other areas where survival data are encountered. Some of these are described in this introductory chapter. This is followed by a description of censoring, which occurs when the end point of a study is not observed for some individuals. After a summary of different types of censoring, some examples of survival data are given that are used throughout the book to illustrate the methods. The chapter also introduces the survivor and hazard functions, and their interrelationships, that are central to the analysis of survival data.
