论文标题
通过功能校准，异步和容易出错的纵向数据分析
Asynchronous and Error-prone Longitudinal Data Analysis via Functional Calibration
论文作者
论文摘要
在许多纵向设置中，时间变化的协变量可能不会与响应同时测量，并且通常容易出现测量误差。幼稚的最后观察前向方法会产生估计偏差，现有的基于内核的方法的收敛速率缓慢和差异很大。为了应对这些挑战，我们提出了一种新的功能校准方法，以基于稀疏功能数据和测量误差的稀疏功能数据有效地学习纵向协变量。我们的方法来自功能性主成分分析，从观察到的异步和容易出现错误的协变量值中校准未观察到的同步协变量值，并广泛适用于异步纵向回归与时间传播或时间变化的系数。对于随时间不变系数的回归，我们的估计量是渐近的，无偏的，根-N一致的，并且渐近地正常。对于时变系数模型，我们的估计器具有最佳的变化系数模型收敛速率，而校准的渐近方差膨胀。在这两种情况下，我们的估计器呈现渐近特性优于现有方法。拟议方法的可行性和可用性通过模拟和全国妇女健康研究的应用来验证，这是一项大规模的多站点纵向研究，对中年妇女健康。
In many longitudinal settings, time-varying covariates may not be measured at the same time as responses and are often prone to measurement error. Naive last-observation-carried-forward methods incur estimation biases, and existing kernel-based methods suffer from slow convergence rates and large variations. To address these challenges, we propose a new functional calibration approach to efficiently learn longitudinal covariate processes based on sparse functional data with measurement error. Our approach, stemming from functional principal component analysis, calibrates the unobserved synchronized covariate values from the observed asynchronous and error-prone covariate values, and is broadly applicable to asynchronous longitudinal regression with time-invariant or time-varying coefficients. For regression with time-invariant coefficients, our estimator is asymptotically unbiased, root-n consistent, and asymptotically normal; for time-varying coefficient models, our estimator has the optimal varying coefficient model convergence rate with inflated asymptotic variance from the calibration. In both cases, our estimators present asymptotic properties superior to the existing methods. The feasibility and usability of the proposed methods are verified by simulations and an application to the Study of Women's Health Across the Nation, a large-scale multi-site longitudinal study on women's health during mid-life.
