The internal consistency of the moral injury event scale

The Moral Injury Event Scale (MIES) is a tool for measuring exposure to potentially morally injurious event(s) and distress. Although it reported acceptable psychometric properties in its initial development studies, it has since been used in multiple contexts and populations without assessment of its changing properties. A reliability generalization of the MIES and its Sub-Scales was therefore undertaken. A systematic search of electronic databases (PsychINFO; PTSD Pubs; MEDLINE; Scopus; Web of Science) identified 42 studies reporting internal consistencies (Cronbach’s α) up to April 2022. Unfortunately, few studies reported any other form of reliability or validity metric (e.g., test-retest, inter-rater reliability). A random effects model with a Bayesian analytic framework and the DerSimonian-Laird (1986) estimate was used. The review found the MIES to be an internally consistent tool based on α estimates at both Full-scale (α = .88; 95% CI [.87–.89]) and Sub-scales (α = .82–.92; 95% CI [.79–.93]). The review uncovered high heterogeneity and inconsistencies in its administration and modification although figures generally remained above acceptable levels (α ≥ .70). Based on the review, the MIES represents an internally reliably tool for measuring potentially morally injurious events and distress at both Full and Sub-Scales according to pooled Cronbach’s α estimates.