Section III of the Diagnostic and Statistical Manual of Mental Disorders (5th edi.; DSM–5; American Psychiatric Association, 2013) contains a system for diagnosing personality disorder based in part on assessing 25 maladaptive traits. Initial research suggests that this aspect of the system improves the validity and clinical utility of the Section II Model. The Computer Adaptive Test of Personality Disorder (CAT-PD; Simms et al., 2011) contains many similar traits as the DSM–5, as well as several additional traits seemingly not covered in the DSM–5. In this study we evaluate the convergent and discriminant validity between the DSM–5 traits, as assessed by the Personality Inventory for DSM–5 (PID-5; Krueger et al., 2012), and CAT-PD in an undergraduate sample, and test whether traits included in the CAT-PD but not the DSM–5 provide incremental validity in association with clinically relevant criterion variables. Results supported the convergent and discriminant validity of the PID-5 and CAT-PD scales in their assessment of 23 out of 25 DSM–5 traits. DSM–5 traits were consistently associated with 11 criterion variables, despite our having intentionally selected clinically relevant criterion constructs not directly assessed by DSM–5 traits. However, the additional CAT-PD traits provided incremental information above and beyond the DSM–5 traits for all criterion variables examined. These findings support the validity of pathological trait models in general and the DSM–5 and CAT-PD models in particular, while also suggesting that the CAT-PD may include additional traits for consideration in future iterations of the DSM–5 system.