OBJECTIVES: The Cribari Matrix Method (CMM) is the current standard to identify over/undertriage but requires manual trauma triage reviews to address its inadequacies. The Standardized Triage Assessment Tool (STAT) partially emulates triage review by combining CMM with the Need For Trauma Intervention, an indicator of major trauma. This study aimed to validate STAT in a multicenter sample. METHODS: Thirty-eight adult and pediatric US trauma centers submitted data for 97,282 encounters. Mixed models estimated the effects of overtriage and undertriage versus appropriate triage on the odds of complication, odds of discharge to a continuing care facility, and differences in length of stay for both CMM and STAT. Significance was assessed at p <0.005. RESULTS: Overtriage (53.49% vs. 30.79%) and undertriage (17.19% vs. 3.55%) rates were notably lower with STAT than with CMM. CMM and STAT had significant associations with all outcomes, with overtriages demonstrating lower injury burdens and undertriages showing higher injury burdens than appropriately triaged patients. STAT indicated significantly stronger associations with outcomes than CMM, except in odds of discharge to continuing care facility among patients who received a full trauma team activation where STAT and CMM were similar. CONCLUSIONS: This multicenter study strongly indicates STAT safely and accurately flags fewer cases for triage reviews, thereby reducing the subjectivity introduced by manual triage determinations. This may enable better refinement of activation criteria and reduced workload.