现代医学科研常对病人或研究对象作随访观察,对随访资料经常计算生存率来评价治疗方法的优劣、疾病预后的好坏和保健措施的成效等。常用计算生存率的方法有两种,直接法和寿命表法。直接法计算ｎ年生存率仅能利用活满ｎ年的人数和观察满ｎ年的人数,对于在随访期间死于非研?.. Modern medical research often makes follow-up observations on patients or subjects. The survival rate is often calculated for follow-up data to evaluate the pros and cons of treatment methods, the prognosis of the disease, and the effectiveness of health care measures. There are two methods commonly used to calculate the survival rate, direct method and life table method. The direct method to calculate the n-year survival rate can only use the number of people who have lived n years and the number of people who have observed n years, and died during non-research during the follow-up period..