Some argue that arresting people for minor acts of domestic violence will only increase the seriousness and frequency of the violence. Others argue that arresting suspects of domestic violence will reduce the suspects' use of violence. Three police responses to simple assault were systematically assigned: arrest, 'advice' or informal mediation, and an order to the suspect to leave for 8 hours. The behavior of the suspect was traced for 6 months after the police intervention with a variety of measures. Preliminary analysis of the official recidivism measures suggests that the arrested suspects manifested significantly less violence than those who were ordered to leave and less violence than those who were advised but not separated. Other interpretations of the results are possible, but if this one is correct, it suggests that police should reverse their current practice of rarely making arrests and frequently separating the parties. The findings suggest that other factors being equal, arrest may be the most effective approach and separation may be the least effective approach. However, since other factors are not usually equal, it cannot be concluded that arrest should be mandatory in all cases of simple domestic assault. Figures and 28 references are supplied. (Author abstract modified)