M. Inkelas et al., Dimensionality and reliability of the Civilian Mississippi Scale for PTSD in a postearthquake community, J TRAUMA ST, 13(1), 2000, pp. 149-167
This study examines psychometric properties of the Civilian Mississippi Sca
le for posttraumatic stress disorder when administered in a community surve
y of 656 persons following the 1989 Loma Prieta earthquake. Internal consis
tency was lower (Cronbach's alpha = .73) than for previous analyses of civi
lian and combat versions of the Mississippi Scale. The analysis produced on
e strong factor composed of 25 items with regular wording and a second weak
er factor composed of 10 items with reversed wording. Internal consistency
was higher when the 10 reversed items were removed (Cronbach's alpha = .86)
; the two factors were negatively correlated Traumatic experiences and psyc
hological distress measures explained more variance in the 25-item factor t
han in the 35-item scale. Further studies should focus on content analysis
and performance of the reversed items.