The Protocol Assessment Tool (PAT) was developed to evaluate changes in the quantity and quality of ED partner violence protocols between 1992 and 1997. This study reviewed and scored 271 written protocols from EDs in California and a national sample. Project staff members scored each protocol based on the PAT. Findings indicated significant improvement in written partner violence protocols in 1996 to 1997 compared to those of 1992 to 1993. There is room for further improvement. In the 1996 to 1997 study, the percentage of EDs with protocols were still short of the target of 90 percent set by Healthy People 2000, and on average, most of the protocols did not meet the criteria established in the PAT. It appears likely that the California laws have impacted EDs’ response to abused patients. Compliance rates in California EDs protocols submitted in 1996 to 1997 were high, particularly the requirement to report partner violence victims to the police. This suggests that a legal requirement that carries a specific penalty may be an effective tool to mold the policies and practices of health care organizations. Mandatory reporting laws are intended to improve documentation and data collection, increase the awareness and response of health care providers and law enforcement officials, hold perpetrators accountable, and increase patient safety. However, abused women have expressed several concerns about mandatory reporting. Laws without specific penalties appear to have less influence on protocol content and health care practice. This study suggests that education and advocacy efforts have improved ED protocols, although the effects of the protocols on actual patient care or patient outcomes have not been assessed. The study results are consistent with the notion that a coordinated, interdisciplinary effort with specific goals may over time improve institutional responses to partner abuse. 3 tables, appendix, 5 notes, 24 references