Estimation of the Average Hazard Ratio
针对删失失效时间数据的两样本问题，提出了平均风险比的简单估计量，并与比例风险类中的偏似然估计量进行比较，发现当风险比不太大时效率通常较好。
Simple estimators of the average hazard ratio are obtained for the two sample problem with censored failure time data. These estimators are compared with estimators arising out of the partial likelihood within the proportional hazards class. Efficiency results are found to be generally quite favourable provided the hazard ratio is not too large. Some comments are made on extensions to the k sample problem.