The partners in the Locally Initiated Research Partnerships share responsibility throughout the course of the project. They jointly select a topic of interest to the police agency and collaborate on the research design, its implementation, and the interpretation of the study findings. The NIJ partnership program in policing began in 1995 and currently consists of 41 research projects. Factors that increase the chance of success of partnerships between police agencies and researchers include a foundation of trust and open communication, good working relationships, efforts by researchers to understand the local police culture, the use of graduate students, information systems, local research products that fit their audience, and retention of the same core group of staff over a multiyear project. Measures of success include whether the department changes as a result of the research, whether information systems have been developed or improved, and whether the partnership continues beyond the life of the initial research project. The partnership forged in Seattle to improve police handling of domestic violence exemplifies the way locally initiated research can change a police agency's approach to reducing crime. Case examples, discussions of the action research model and new research areas, figure, list of projects, and notes