Published in Nursing Research, the following study assesses the effectiveness of a violence-prevention intervention, on the basis of social cognitive theory to increase knowledge, self-efficacy, and skills, and to decrease assaults. The intervention participants showed significant increases in knowledge, self-efficacy, and violence-prevention skills. The intervention had a significant effect on the incidence of assaults for nursing assistants who had fewer than 6 incidents pre-intervention. Significant relationships between assaults and the covariates, age, state anger, and the number of residents assigned, were found.