Factor structure and psychometric properties of the Insomnia Severity Index in Mainland China

We explored the factor structure and psychometric properties of the Insomnia Severity Index (ISI) using 3 samples totaling 2,066 Mainland Chinese undergraduates. All participants completed the ISI and Sample 2 completed 3 other related measures. Their responses were processed using exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and multiple group analyses. The EFA results revealed a 2-factor structure, whereas the CFA results supported a 3-factor solution, the latter of which was further confirmed by the results of multiple group analyses. The Chinese version of the ISI had a satisfactory Cronbach's alpha coefficient of internal reliability, 2-week test–retest reliability, and criterion validity. Overall, we found that the ISI is a reliable, valid, and psychometrically sound measure of insomnia for use with Mainland Chinese undergraduates.