The Alternative Model of Personality Disorders (AMPD) in Section III of the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, text revision includes trait-based diagnostic criteria for six personality disorders (PDs). This study evaluates the predictive validity of the AMPD trait diagnostic criteria for these six PDs in capturing their Section II PD counterparts and examines whether modifications informed by meta-analytic findings (Watters et al., 2019) improve incremental validity. In community (N = 238) and community mental health samples (N = 289), we assessed Section III traits using the Personality Inventory for Diagnostic and Statistical Manual of Mental Disorders, fifth edition and Section II PDs using three different measurement methods-structured clinical interview, self-report, and informant report. A series of hierarchical regressions tested the extent to which proposed traits predicted their Section II counterparts and whether the inclusion of nondesignated traits or removal of proposed traits enhanced predictive validity. Findings confirmed that Section III proposed traits significantly predicted their corresponding Section II PDs. Results also revealed that some proposed traits failed to significantly contribute to their assigned PDs, while certain nonproposed traits improved predictive validity. Based on these results, we propose targeted, empirically informed modifications to the AMPD diagnostic trait sets to improve construct validity and clinical utility, particularly for avoidant, borderline, narcissistic, and obsessive-compulsive PDs. These findings underscore the need to refine the AMPD trait model to better capture the complexity of personality pathology. (PsycInfo Database Record (c) 2026 APA, all rights reserved).