The Devereux Student Strengths Assessment Mini (DESSA-Mini; Naglieri, LeBuffe, & Shapiro, 2011/2014) was designed to overcome practical obstacles to universal prevention screening. This article seeks to determine whether an entirely strength-based, 8-item screening instrument achieves technical accuracy in routine practice. Data come from a district-wide implementation of a new social emotional learning (SEL) initiative designed to promote students' social-emotional competence. All students, kindergarten through Grade 8, were screened using the DESSA-Mini. A random 5 students per classroom received additional assessment. Concurrent and predictive criterion studies were conducted using the full DESSA as well as administrative records of serious disciplinary infraction. The DESSA-Mini showed excellent internal reliability, exceeding .90. Negligible to small differences were found between scores on the DESSA-Mini screen and the DESSA full assessment. Classification consistency between the DESSA-Mini and the DESSA was high (87%-94%) in routine practice, with sensitivity and specificity estimates exceeding Glascoe's (2005) standards. Finally, predictive validity of the DESSA-Mini was reliable; students screened as having a Need for SEL Instruction at the beginning of the year were 4.5 times more likely to have a record of serious disciplinary infraction at the end of the school year compared with those who were not identified (p < .001). These findings compare quite favorably with other instruments used in schools to screen entire student populations, in cases where such analyses have been conducted, and is consistent with a practice preference of identifying, but not overidentifying, students for accelerated preventative interventions for mental, emotional, and behavioral problems. (PsycINFO Database Record