A confirmatory factor analysis of the Impact of Event Scale using a sample of World War II and Korean War veterans

This study assessed the factor structure of the Impact of Event Scale (IES), a measure of intrusion and avoidance, using a sample of World War II and Korean War veterans who had experienced combat 40-50 years earlier. A series of 3 confirmatory factor analytic models were specified and estimated using LISREL 8.3. Model 1 specified a 1-factor model. Model 2 specified a correlated 2-factor model. Model 3 specified a 2-factor model with additional cross-factor loadings for Items 2 and 12. Model 3 was found to fit the data. In addition, this model was found to be a better explanation of the data than the other models. Also in addition, the correlations between the Intrusion and Avoidance factors and the 4 subscales of the 28-item General Health Questionnaire were examined to determine the distinctiveness of the two IES factors.

Gender differences in the reliability of the EPQ? A bootstrapping approach

Reliability indicates the degree of stability or homogeneity of a measurement, but also places an upper limit on the degree of association with other variables. Various methods are available to estimate the reliability of a measurement scale. However, an issue that has rarely been examined is that the reliability of a measurement, as estimated by coefficient alpha, may differ between groups. If a measurement has a different reliability for groups within a sample, spurious moderator effects may occur. The present study examines the reliability of the four subscales of a widely used psychological measurement instrument, the Eysenck Personality Questionnaire-Revised (EPQ-R), across gender. A bootstrapping methodology is employed which allows empirically derived standard errors to be calculated, and therefore tests of significance of difference to be computed. No significant differences were found in the reliability of the EPQ-R across sexes.