The model protocol is designed for adoption or modification by police departments throughout Pennsylvania. It was developed by an interdisciplinary task force consisting of law enforcement professionals and other representatives of government and private agencies, victim advocates, and academics. The overview presents definitions of domestic violence, an explanation of its scope and nature, characteristics of perpetrators and victims, causation and dynamics, the response of the criminal justice system, and responses of other government agencies. The protocol's central feature is the provision that police should arrest the assailant in domestic violence cases whenever arrest is authorized. Responding officers who do not make arrests should include in their reports a detailed explanation of why an arrest was not made. Police should also identify the victim. The protocol outlines dispatch procedures, the initial police officer response, the arrest decision, the handling of the arrest, the procedure when an arrest is not authorized or made, other on-scene assistance to victims and dependents, the processing of the accused, encouragement of follow-through by victims, and the written report and data collection. Recommendations for each group of criminal justice professionals responsible for implementing the protocol and 294 reference notes.