[Survival analysis--the method used to analyze the follow-up data].

In clinical research, the collected data covers a kind of special data that named follow-up data. However, long time's follow-up is necessary when to evaluate the effect of certain drugs or operations on the patients. During this process, various kinds of outcome and different follow-up times will be found among patients. Survival analysis is a kind of statistical methods that connect outcome with survival time and co-analyze them. This statistical method is used to analyze completed data and uncompleted data at the same time, which can make the best use of the information in medical research to evaluate and compare the follow-up data more exactly. This review introduces the basic principle and method of survival analysis.