The Principal Research Core (PRC) of the Center for Research to Improve Mental Health Care in the Social Services (C-RIMMS) will support the generation, implementation, and maturation of a research agenda that addresses the most pressing issues in current health policy: quality of mental health care, quality for vulnerable populations, and quality improvement through settings with the highest potential to reduce racial and ethnic disparities. Our practice and systems research will be conducted in partnership with social service agencies, where prevalence of mental disorder is high and the most vulnerable of clients predominate. Five proposed pilot studies will address three aims: (1) understand what constitutes quality of care for mental disorders in the social services from the perspective of key stakeholders; (2) within the context of competing demands, assess practice variation in quality of care and identify provider, client, and system ecostructure influences (including financing) on that variation; and (3) working "trench to bench and back to trench," develop and test a menu of quality improvements for mental health care in social service agencies. Led by muttidisciplinary teams, each pilot study will use resources of the Operations Core, employ mixed methods in sequence or concurrently, benefit from agency partnerships and stakeholder networks developed in the Research Network Development Core, and be informed by methods teams in the Research Methods Core. All pilots will lead to NIMH R01, R03, R21, and R34 grant proposals. The incorporation of"local knowledge" from setting-specific clients and contexts (i.e., payers, administrators, front-line providers, consumers, family members, mental health advocates) will guide our efforts to develop acceptable and durable quality improvements. Leveraging social service settings to reach and treat persons with mental disorder has high potential to ensure treatment to persons whose disorder currently goes undetected, to improve care for those now poorly served, and to reduce disparities in care. This agenda is highly responsive to priorities reflected in the President's New Freedom Commission Report on Mental Health, IOM Quality of Care, Surgeon General's and Bridging Science and Services reports.