Objective: The Level of Stability Index for Children (LSIC) is a multidimensional, self-report, rapid assessment instrument for assessing emotional and behavioral tendencies children may exhibit toward self or others. The LSIC describes children's propensity toward depression, suicidal ideation, anger, and aggression. Method: Self-report survey instruments, including the LSIC and two measures for construct validation, were administered to a purposive sample of 426 children from various school and agency settings. Results: Strong evidence was found for reliability, content, and factorial validity. Alpha coefficients ranged from 0.74 to 0.87 for LSIC subscales. Confirmatory factor analyses were conducted using the multiple group method and structural equation modeling. Convergent and discriminant analyses produced preliminary evidence for LSIC construct validity. Conclusion: The LSIC showed strong evidence of reliability and validity for younger children (7-12) and adolescents (13-18). Assessment tools can shed light on the complex mental health issues that social workers encounter when working with children in care. (Contains 7 tables and 1 figure.)