论文标题
通过加权z差异来测量加权倾向得分分析的协变量平衡
Measuring covariate balance in weighted propensity score analyses by the weighted z-difference
论文作者
论文摘要
近年来，在评估非随机研究中的治疗效果时，倾向评分（PS）方法已越来越多地使用。在统计方法方面，开发了许多新的PS加权方法，并且表明它们可以在不同仿真设置中的治疗效应估计效率上匹配PS的表现。为了评估治疗组中协变量的平衡，PS加权方法通常使用加权标准化差异，尽管此措施的某些不足，例如，例如，根据样本量和权重分布，加权标准化差异的分布。我们将加权Z差异作为PS加权分析中的平衡度量引入，并在模拟研究中证明了其用法，并将其应用于心脏手术的示例。加权z差异在计算上很简单，可以针对连续，二进制，序数和名义协变量计算。通过使用Q-Q曲线，我们可以将PS加权样品的平衡与完美匹配的PS样本中的平衡以及在随机试验中的预期平衡中进行比较。
Propensity score (PS) methods have been increasingly used in recent years when assessing treatment effects in nonrandomized studies. In terms of statistical methods, a number of new PS weighting methods were developed, and it was shown that they can outperform PS matching in efficiency of treatment effect estimation in different simulation settings. For assessing balance of covariates in treatment groups, PS weighting methods commonly use the weighted standardized difference, despite some deficiencies of this measure like, for example, the distribution of the weighted standardized difference depending on the sample size and on the distribution of weights. We introduce the weighted z-difference as a balance measure in PS weighting analyses and demonstrate its usage in a simulation study and by applying it to an example from cardiac surgery. The weighted z-difference is computationally simple and can be calculated for continuous, binary, ordinal and nominal covariates. By using Q-Q-plots we can compare the balance of PS weighted samples immediately to the balance in perfectly matched PS samples and to the expected balance in a randomized trial.
