In health research interest often lies in modeling a failure time process but in many cohort studies failure status is only determined at scheduled assessment times. While the assessment times may be fixed upon study entry, individuals may become lost to follow‐up and miss visits subsequent to the time of loss to follow‐up. We consider a three‐state model to characterize a joint failure and loss to follow‐up process, and use it to investigate the impact of dependent loss to follow‐up on standard parametric, nonparametric, and semiparametric analysis. The effect of dependent loss to follow‐up is mitigated by fitting the joint model. The performance of standard methods is studied using the asymptotic theory of misspecified models, and the finite sample performance is examined for the standard and joint analyses through simulation studies. An application to data from a youth smoking prevention study is presented for illustration.

中文翻译：

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故障时间研究，间歇性观察和后续损失

在健康研究中，兴趣通常在于对故障时间过程进行建模，但是在许多同类研究中，故障状态仅在计划的评估时间确定。虽然评估时间可能会在研究进入时确定，但个人可能会失去随访的机会，并在失去随访时间之后错过探访机会。我们考虑了一种三态模型来表征关节失灵和后续随访过程的损失，并使用它来研究因后续随访而引起的相关损失对标准参数，非参数和半参数分析的影响。通过拟合联合模型，可以减轻因损失对随访的影响。使用错误指定模型的渐近理论研究标准方法的性能，并通过模拟研究检查标准和联合分析的有限样本性能。