In 2010, the Agency for Healthcare Research and Quality (AHRQ) charged the Oregon Evidence-based Practice Center with conducting a Comparative Effectiveness Review (CER) to assess the effectiveness of outpatient case management as an intervention strategy for chronic illness management. The Key Questions the review addressed were: Key Question 1. In adults with chronic medical illness and complex care needs, is case management effective in improving: 1a. Patient-centered outcomes, including mortality, quality of life, disease-specific health outcomes, avoidance of nursing home placement, and patient satisfaction with care? 1b. Quality of care, as indicated by disease-specific process measures, receipt of recommended health care services, adherence to therapy, missed appointments, patient self-management, and changes in health behavior? 1c. Resource utilization, including overall financial cost, hospitalization rates, days in the hospital, emergency department use, and number of clinic visits (including primary care and other provider visits)? Key Question 2. Does the effectiveness of case management differ according to patient characteristics, including but not limited to: particular medical conditions, number or type of comorbidities, patient age and socioeconomic status, social support, and/or level of formally assessed health risk? Key Question 3. Does the effectiveness of case management differ according to intervention characteristics, including but not limited to: practice or health care system setting; case manager experience, training, or skills; case management intensity, duration, and integration with other care providers; and the specific functions performed by case managers?