Rasmussen et al. (2019) described the proliferation of factors for posttraumatic stress disorder (PTSD) measures and raised concerns about the construct validity of factors that include two or three items. In this brief report, we describe how the pattern of covariation among the responses to items of well-established measures, such as the PTSD Checklist for DSM-5 (PCL-5), can give the appearance of multidimensionality. We evaluated whether the structure of the 20-item PCL-5 is unidimensional, using the methods of multidimensional item response theory (MIRT) and the concept of a testlet. These analyses were done using a sample of trauma-exposed urban firefighters. A unidimensional and a bifactor model, which includes a general factor composed of all items and four specific factors mirroring the DSM-5 conceptualization, were evaluated for both Likert-type multiple-category and binary coding system of the PCL-5 item response data. Seven testlets were created from the 20 PCL-5 items following the seven-factor model (Armour et al., 2015) presented in Table 1 of Rasmussen et al. (2019). Findings using the unidimensional nominal item response theory model for the seven testlets indicated that the PCL-5 may be considered unidimensional with a single score representing individual differences on a continuum that ranges from low to high. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

中文翻译：

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多维性的出现：使用消防员样本探索 DSM-5 PTSD 检查表的单维性案例。


拉斯穆森等人。 (2019) 描述了创伤后应激障碍 (PTSD) 测量因素的激增，并对包含两个或三个项目的因素的构建有效性提出了担忧。在这份简短的报告中，我们描述了对既定测量项目（例如 DSM-5 的 PTSD 检查表（PCL-5））的响应之间的协变模式如何呈现出多维性的外观。我们使用多维项目反应理论 (MIRT) 和 testlet 的概念来评估 20 项目 PCL-5 的结构是否是一维的。这些分析是使用受过创伤的城市消防员样本进行的。一维和双因素模型（包括由所有项目组成的一般因素和反映 DSM-5 概念化的四个特定因素）针对 PCL-5 项目响应数据的 Likert 型多类别和二进制编码系统进行了评估。根据 Rasmussen 等人的表 1 中所示的七因素模型（Armour 等人，2015 年），从 20 个 PCL-5 项目中创建了 7 个测试集。 （2019）。对七个小测试使用一维名义项目反应理论模型的结果表明，PCL-5 可以被认为是一维的，单个分数代表从低到高的连续体上的个体差异。 （PsycInfo 数据库记录 (c) 2024 APA，保留所有权利）。