Development and Validation of the Simplified Chinese Version of the Injustice Experience Questionnaire with Cross-Cultural Adaptation

In the context of pain and pain-related disability, perceived injustice is conceptualized as an appraisal process characterized by a tendency to view one’s losses as severe and irreparable and attribute blame for one’s suffering to others. Previous research measured perceived injustice using the Injustice Experiences Questionnaire (IEQ). However, a Simplified Chinese language version of the IEQ (IEQ-SC) is required for the population who use Simplified Chinese. This study aimed to develop the IEQ-SC and examine its psychometric properties. The IEQ-SC was administered to 212 patients with musculoskeletal injury aged 21–83 years who visited the hospital. Participants completed several patient-reported outcome measures: the IEQ-SC, the Pain Catastrophizing Scale (PCS), the Brief Pain Inventory (BPI) pain intensity measured by a numerical rating scale (NRS), and the BPI pain interference. The factor structures of the IEQ-SC were investigated using exploratory and confirmatory factor analysis. Construct validity was assessed between the IEQ-SC and PCS, NRS, and BPI pain interference using Pearson’s correlation coefficients. Internal consistency was evaluated with Cronbach’s α, and test–retest reliability was evaluated with intraclass correlation coefficients (ICC). The two-factor model, which was identical to the IEQ-SC factor structure and had good fit indices, differs from both the original two-factor model and the three-factor model identical to the Japanese version. The IEQ-SC demonstrated adequate construct validity and high internal consistency and reliability (Cronbach’s alpha = 0.92; ICC = 0.97). Preliminary analyses suggest the IEQ-SC is a reliable and valid measure of pain-related injustice perceptions among Chinese patients with musculoskeletal injury.