Comparison of Three Psychological Defense Mechanism Questionnaires

The Defense Mechanisms Inventory (DMI), the Coping Operations Preference Enquiry (COPE), and the scales developed by Joffe and Naditch (J&N) were compared using multitrait-multimethod logic. Convergent validity was tow as measures of the same defense were not highly correlated across instruments. Similar patterns of correlations occurred within instruments but the J&N scales, and particularly the DMI scales, had high interscale correlations so overall discriminant validity was limited. These results suggest that either the defense constructs or at least some of the defense scales studied lack validity. Another possibility is that the scales are valid, but assess different parameters of defensiveness (e.g., intensity versus breadth of use of mechanisms). Comparisons of the scales' predictive validity should help resolve these points.