Development and validation of a daily Injustice Experience Questionnaire.

BACKGROUND

Patterns of cognitive appraisal related to chronic pain may manifest differentially across time due to a variety of factors, but variability of injustice appraisals across time has not been examined. The current study details the validation of a brief, daily version of the Injustice Experience Questionnaire (IEQ), which measures injustice appraisals related to the experience of pain and disability.

METHODS

Injustice Experience Questionnaire items were adapted for daily use and evaluated using cognitive interviews, and the resulting measure was administered for 10 days to two Internet-based samples of US adults with chronic lower back pain.

RESULTS

Study 1 (N = 126) refined the 12-item IEQ measure into a six-item short form; exploratory factor analyses suggested optimal model fit for the two-factor model established in the original IEQ. Using confirmatory factor analyses, Study 2 (N = 131) replicated the two-factor structure and demonstrated significant correlations of the Daily IEQ with other relevant constructs to chronic pain, such as pain catastrophizing, pain intensity, pain-related activity and social interference, depressed mood and anxiety. Daily IEQ items showed a significant degree of clustering (intraclass correlations ranging from .577 to .735) but demonstrated sufficient variability at the daily level to allow for daily-level analysis.

CONCLUSIONS

Injustice appraisals show a sufficient degree of daily variability to warrant their measurement as a time-varying construct. Further examination of antecedents and correlates of daily injustice appraisals, as well as their potential role as mechanisms of effect, may better explain the dynamics of affective and behavioral responses to chronic pain.

SIGNIFICANCE

The current study presents a validation of a daily version of the Injustice Experience Questionnaire in chronic low back pain. Results indicate that injustice appraisals vary significantly from day to day, and daily variability in injustice perception shows robust associations with pain intensity, pain-related interference in physical and social activity, and mood in chronic low back pain. These results emphasize the importance of assessing injustice perception as a time-varying, rather than stable construct in future empirical and clinical studies.