Internal and external validity of the BIDR was examined in college students and with forensic clients. The study also investigated the equivalence of the original format of the BIDR and the revised (the PDS). Results showed the IM scales of the BIDR and the PDS can be regarded as equivalent, but the SDE scales can not. Correlations with concurrent validity scales were generally stronger for the IM scale than the SDE scale. For both groups, the SDE and IM scales were substantially correlated with each other. Analyses of the undergraduate data did not support Paulhus' intention of two major factors for either the BIDR or the PDS; but did show this pattern for forensic data.