Dimensionality and Reliability of the Civilian Mississippi Scale for PTSD in a Postearthquake Community

This study examines psychometric properties of the Civilian Mississippi Scale for posttraumatic stress disorder when administered in a community survey of 656 persons following the 1989 Loma Prieta earthquake. Internal consistency was lower (Cronbach's α = .73) than for previous analyses of civilian and combat versions of the Mississippi Scale. The analysis produced one strong factor composed of 25 items with regular wording and a second, weaker factor composed of 10 items with reversed wording. Internal consistency was higher when the 10 reversed items were removed (Cronbach's α = .86); the two factors were negatively correlated. Traumatic experiences and psychological distress measures explained more variance in the 25-item factor than in the 35-item scale. Further studies should focus on content analysis and performance of the reversed items.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43098/1/10960_2004_Article_221433.pd