Radboud University Nijmegen, Institute for Management Research, The Netherlands.
J Psychosom Res. 2013 Aug;75(2):167-72. doi: 10.1016/j.jpsychores.2013.03.013. Epub 2013 Apr 25.
Several authors proposed a shortened version of the State scale of the State-Trait Anxiety Inventory (S-STAI) to obtain a more efficient measurement instrument. Psychometric theory shows that test shortening makes a total score more vulnerable to measurement error, and this may result in inaccurate and biased research results and an increased risk of making incorrect decisions about individuals. This study investigated whether the reliability and the measurement precision of shortened versions of the S-STAI are adequate for psychological research and making decisions about individuals in clinical practice.
Secondary data analysis was used to compare reliability and measurement precision between twelve shortened S-STAI versions and the full-length 20-item S-STAI version. Data for the 20-item version came from a longitudinal study performed previously in the Netherlands and included 377 patients and 375 of their family members. This was our master data set. A literature study was conducted to identify shortened S-STAI versions that are used in research and clinical practice. Data for each shortened version were obtained from the master data set by selecting the relevant items from the 20-item version. All analyses were done by means of classical test theory statistics.
The effect of test shortening on total-score reliability was small, the effect on measurement precision was large, and the effect on individual diagnosis and assessment of individual change was ambiguous.
We conclude that shortened versions of the S-STAI seem to be acceptable for research purposes, but may be problematic in clinical practice.
一些作者提出了状态特质焦虑量表（STAI）的缩短版，以获得更高效的测量工具。心理测量理论表明，测试缩短会使总分更容易受到测量误差的影响，这可能导致不准确和有偏见的研究结果，并增加对个体做出错误决策的风险。本研究旨在探讨缩短版 STAI 的可靠性和测量精度是否足以进行心理研究和对临床实践中的个体做出决策。
我们使用二次数据分析来比较 12 种缩短版 STAI 版本与全长 20 项版 STAI 版本之间的可靠性和测量精度。20 项版本的数据来自先前在荷兰进行的一项纵向研究，包括 377 名患者及其 375 名家庭成员。这是我们的主数据集。我们进行了一项文献研究，以确定在研究和临床实践中使用的缩短版 STAI 版本。通过从 20 项版本中选择相关项目，从主数据集中获取每个缩短版的数据。所有分析均采用经典测试理论统计方法进行。
测试缩短对总分可靠性的影响较小，对测量精度的影响较大，对个体诊断和个体变化评估的影响则不确定。
我们的结论是，STAI 的缩短版似乎可以接受用于研究目的，但在临床实践中可能存在问题。
