Department of Education and Psychology, Campus Universitário de Santiago, University of Aveiro, Aveiro, Portugal.
Sleep Medicine Centre, Coimbra University Hospital Centre (CHUC), Coimbra, Portugal.
J Sleep Res. 2023 Aug;32(4):e13835. doi: 10.1111/jsr.13835. Epub 2023 Feb 3.
The aim of the current study was to conduct a reliability generalisation (RG) meta-analysis of Cronbach's alpha for the Insomnia Severity Index (ISI). A systematic search of three databases (PubMed, Scopus, and Web of Science) from inception to 12 March 2021 was performed. Publications that reported Cronbach's alpha for the total ISI score were included. Only psychometric-focussed studies were considered. Meta-analysis was carried out using a random-effects model to derive a pooled estimate of Cronbach's alphas. The number of participants in the included publications ranged from 25 to 12,056, with 33 studies (42 estimates) comprising internal consistency coefficients, and a combined sample size of N = 29,688. The age range of the included publications was from 13.4 to 74.3 years. Data extraction implied 33 publications out of 706 found through the database search. Cronbach's alphas ranged from 0.65 to 0.92. The majority of the reported coefficients were ≥0.7 and presented a low risk of bias (n = 32). The pooled alpha coefficient was 0.83 (IC [0.81-0.85]; SE = 0.009) with high heterogeneity among the included publications (I = 97%). Subgroup analyses including moderators such as continent, setting, risk of bias, and age did not affect significantly the overall result. In general, the cumulative estimate of Cronbach's alpha for the ISI is good. However, this finding should be interpreted with caution since there is a high heterogeneity level and some of the studies might not have checked the assumptions underlying Cronbach's alphas.
本研究旨在对失眠严重程度指数（ISI）的克朗巴赫α进行可靠性综合（RG）元分析。从建库到 2021 年 3 月 12 日，对三个数据库（PubMed、Scopus 和 Web of Science）进行了系统检索。纳入报告 ISI 总分克朗巴赫α的出版物。仅考虑注重心理测量的研究。使用随机效应模型进行元分析，得出克朗巴赫α的汇总估计值。纳入出版物的参与者人数从 25 到 12056 不等，有 33 项研究（42 项评估）包括内部一致性系数，综合样本量为 N=29688。纳入出版物的年龄范围为 13.4 至 74.3 岁。数据提取意味着从数据库搜索中发现的 706 篇文章中提取了 33 篇。克朗巴赫α值范围从 0.65 到 0.92。报告的系数大多为≥0.7，偏倚风险低（n=32）。汇总的α系数为 0.83（IC [0.81-0.85]；SE=0.009），纳入的出版物之间存在高度异质性（I 2=97%）。包括大陆、环境、偏倚风险和年龄等调节因素的亚组分析并没有显著影响总体结果。总体而言，ISI 的克朗巴赫α累积估计值较好。然而，由于存在高度的异质性，并且一些研究可能没有检查克朗巴赫α所依据的假设，因此该发现应谨慎解释。
