PURPOSE Individuals with spinal cord injury (SCI) may experience both positive (posttraumatic growth, PTG) and negative (posttraumatic depreciation, PTD) psychological changes following the injury. PTG and PTD were assessed using the 10-item short form of the Posttraumatic Growth Inventory (PTGI-SF) and 10 matched negatively worded items for PTD (selected from the PTGI-42) within the Swiss Spinal Cord Injury Cohort Study (SwiSCI). This item selection is henceforth called PTG/D-SF. The objective of this study was to test the metric properties of the PTG/D-SF to determine the best strategy to derive reliable sum scores and to test the validity of several different structural conceptualizations. METHOD Using cross-sectional data (N = 278), a series of unidimensional and multidimensional Rasch analyses of the PTG/D-SF (N = 20) were performed. Rasch analyses were conducted separately for the items or by domains to investigate dimensionality, monotonicity, item and model fit, and local item dependency of the instrument. RESULTS The separate PTG and PTD items or their domains can be summated to form a unidimensional scale. Aggregation into domains improved the score distribution and increased the scope of the instruments. The reliability of the sum score for PTG was good (Person Separation: 0.81); the one for PTD was admissible (Person Separation: 0.77). CONCLUSION PTG and PTD should be understood as distinct constructs rather than two ends of a continuum. Findings support the use of a PTG total score and to some degree the PTD total score. Future work could adapt the PTD items to improve the performance of the scale. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

中文翻译：

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测量脊髓损伤后的创伤后生长和贬值：Rasch 分析。

目的 脊髓损伤 (SCI) 患者在受伤后可能会经历积极的（创伤后成长，PTG）和消极的（创伤后贬值，PTD）心理变化。在瑞士脊髓损伤队列研究 (SwiSCI) 中，使用 10 个项目的创伤后成长量表 (PTGI-SF) 的简写形式和 10 个匹配的 PTD 负面措辞项目（选自 PTGI-42）评估 PTG 和 PTD。此项目选择此后称为 PTG/D-SF。本研究的目的是测试 PTG/D-SF 的度量属性，以确定获得可靠总分的最佳策略，并测试几种不同结构概念的有效性。方法 使用横截面数据 (N = 278)，对 PTG/D-SF (N = 20) 进行了一系列单维和多维 Rasch 分析。Rasch 分析分别针对项目或按领域进行，以研究工具的维度、单调性、项目和模型拟合以及局部项目依赖性。结果 可以将单独的 PTG 和 PTD 项目或其域相加以形成一维量表。聚合到域中改善了分数分布并增加了工具的范围。PTG 总分的信度较好（Person Separation：0.81）；PTD 的一个是可以接受的（人的分离：0.77）。结论 PTG 和 PTD 应该被理解为不同的结构，而不是一个连续体的两端。结果支持使用 PTG 总分，并在某种程度上支持使用 PTD 总分。未来的工作可以调整 PTD 项目以提高量表的性能。（PsycINFO 数据库记录 (c) 2019 APA，保留所有权利）。