University of Waikato, School of Psychology, Hamilton, New Zealand.
Centre for Healthy Brain Ageing (CHeBA), Discipline of Psychiatry & Mental Health, School of Clinical Medicine, University of New South Wales, Sydney, Australia.
J Affect Disord. 2023 Jun 1;330:117-124. doi: 10.1016/j.jad.2023.02.116. Epub 2023 Mar 1.
The 10-item Kessler Psychological Distress Scale (K-10) is a widely applied distress measure; however, its psychometric properties were not established with older populations using advanced methodology. The aim of this study was to examine psychometric properties of the K-10 through application of Rasch methodology and if possible, develop an ordinal-to-interval conversion to improve its reliability in older populations.
The Partial Credit Rasch Model was applied to analyse K-10 scores of the sample including 490 participants (56.3 % females) aged 70 to 90 years and without dementia from the Sydney Memory and Ageing Study (MAS).
The initial analysis of the K-10 showed poor reliability and significant deviation from the expectations of the Rasch model. The best model fit was evident after correcting disordered thresholds and creating two testlet models to address local dependency between items (χ(35) = 29.87, p = 0.71). The modified K-10 demonstrated strict unidimensionality, enhanced reliability and scale invariance across personal factors, such as sex, age, and education and permitted development of ordinal-to-interval transformation algorithms.
Ordinal-to-interval conversion can only be applied for older adults with complete data.
The K-10 satisfied principles of fundamental measurement defined by Rasch model after minor modifications. Clinicians and researchers can transform K-10 raw scores into interval-level data using converging algorithms published here without altering the original scale response format, which increases reliability of the K-10.
10 项 Kessler 心理困扰量表（K-10）是一种广泛应用的困扰量表；然而，其心理测量特性并未通过使用先进方法对老年人进行确立。本研究的目的是通过应用 RASCH 方法来检验 K-10 的心理测量特性，并在可能的情况下开发出一种有序到区间的转换，以提高其在老年人中的可靠性。
部分信用 RASCH 模型应用于分析包括 490 名（56.3%为女性）年龄在 70 至 90 岁且无痴呆症的悉尼记忆和衰老研究（MAS）参与者的 K-10 评分。
K-10 的初步分析显示可靠性差，且明显偏离 RASCH 模型的预期。在纠正无序阈值并创建两个测试项模型以解决项目之间的局部依赖性（χ(35) = 29.87，p = 0.71）后，最佳模型拟合变得明显。修正后的 K-10 表现出严格的单维性，提高了可靠性和跨个人因素（如性别、年龄和教育）的量表不变性，并允许开发有序到区间的转换算法。
有序到区间的转换只能应用于具有完整数据的老年人。
经过微小修改，K-10 符合 RASCH 模型定义的基本测量原则。临床医生和研究人员可以使用此处发布的收敛算法将 K-10 原始分数转换为区间水平数据，而无需改变原始量表的响应格式，从而提高 K-10 的可靠性。
