Confirmatory factor analysis of the Injustice Experience Questionnaire in an Australian compensable population

This study examined the factor structure of the Injustice Experience Questionnaire (IEQ; Sullivan et al. in J Occup Rehabil 18:249-261, 2008) using confirmatory factor analysis (CFA). Two models were proposed for analysis: a single factor and a two-factor model.

A total of 150 participants (81 males and 69 females, mean age = 45.48 years, SD = 10.71), with a chronic work-related musculoskeletal disorder (53 % back condition), and a mean duration of work disability of 4.34 years (SD = 5.14), completed the IEQ and measures of depression and anger. CFA was performed on the IEQ data using the maximum likelihood estimation method.

Neither proposed model provided an acceptable fit; however, a good fitting model with two highly correlated factors and one error covariance was derived through post hoc model fitting. The two-factors were differentially correlated to depression and duration of work disability, but not anger.

The IEQ appears to be a useful tool to support the comprehensive psychosocial assessment of injured workers with long-term disability secondary to a musculoskeletal disorder. In addition to identifying perceived injustice, the IEQ may also be used to inform the choice of psychological interventions. The IEQ has construct validity and generalizability across different populations of injured workers.