Rasch analysis of the firefighters’ critical incident inventory questionnaire

BACKGROUND: The Critical Incident Inventory (CII) was developed to assess stressful exposures in firefighters and emergency service workers. The CII includes six subscales: trauma to self, victims known to fire-emergency worker, multiple casualties, incidents involving children, unusual or problematic tactical operations, and exposure to severe medical trauma. OBJECTIVES: To examine the construct validity of all subscales of the Critical Incident Inventory (CII) by assessing the unidimensionality of the scales, and the interval properties of CII subscales by examining fit to the Rasch model and ordering of item thresholds. METHODS: This was a secondary data analysis based on survey data collected from a sample of 390 firefighters. RESULTS: Item 4 and Item 20 were removed with the confirmation of unacceptable fit residual. This revised version of the CII showed satisfactory fit to the Rasch model by non-significant Chi-square test and acceptable level of item fit. We rescored the CII original version and considered all items as only dichotomous response options where 0 represented the original no experience, and 1 presents the combination of experiencing 1, 2, 3 cases. CONCLUSION: The re-appraisal of the revised version CII indicated a satisfactory level of Rasch model fit.