Intensive longitudinal studies are becoming increasingly popular because of their potential for studying the individual dynamics of psychological processes. However, measures used in such studies are quite susceptible to measurement error due to the short lengths and therefore their psychometric properties, such as reliability, are of great concern. Most existing approaches for assessing reliability are not appropriate for the intensive longitudinal data (ILD) because of the conflation of inter- and intra-individual variations or the difficulty in handling interindividual differences. In addition, measurement models are always relegated or omitted in the ILD modeling approaches. Therefore, in this article, we introduce a two-level random dynamic measurement (2RDM) model for ILD, which takes into account measurement models for key variables of interest. Then we discuss how to derive the within-person and between-person reliabilities for items and scales in the context of the 2RDM model. A small simulation study is presented to illustrate the implementation of the 2RDM model and reliability estimation. An empirical study is then provided to demonstrate the application of the proposed approach for multidimensional scales, in which we calculated the within- and between-person reliabilities for both items and subscales of a short version of the Perceived Stress Scale and found large individual differences in the within-person reliabilities. We conclude by discussing the advantages and considerations of the proposed approach in practice. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

中文翻译：

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在密集纵向研究中评估个体内和个体内的可靠性：基于两级随机动态模型的方法。

密集的纵向研究变得越来越受欢迎，因为它们具有研究心理过程的个体动态的潜力。然而，此类研究中使用的测量由于长度短而很容易出现测量误差，因此其心理测量特性（例如可靠性）受到极大关注。大多数现有的可靠性评估方法不适合密集纵向数据（ILD），因为个体间和个体内差异的合并或难以处理个体间差异。此外，测量模型在 ILD 建模方法中总是被降级或省略。因此，在本文中，我们介绍了 ILD 的两级随机动态测量（2RDM）模型，该模型考虑了感兴趣的关键变量的测量模型。然后我们讨论如何在 2RDM 模型的背景下导出项目和量表的人内和人间可靠性。提出了一个小型仿真研究来说明 2RDM 模型和可靠性估计的实现。然后提供了一项实证研究来证明所提出的方法在多维量表中的应用，其中我们计算了短版感知压力量表的项目和子量表的人内和人际可靠性，并发现了巨大的个体差异人体内的可靠性。最后，我们讨论了所提出的方法在实践中的优点和考虑因素。（PsycInfo 数据库记录 (c) 2023 APA，保留所有权利）。