Accurately measuring the quality of chronic illness care for older adults is essential to improving the organization and delivery of chronic illness care to this population. This dissertation focuses on measuring quality of care for individuals and groups. The first part of the dissertation measures the technical quality of osteoarthritis care for adults age 75 and older who were participating in an unrelated quality improvement initiative, Assessing Care of Vulnerable Elders -2 (ACOVE-2). Patients received 57% of recommended care for osteoarthritis. The second part of the dissertation tests for unintended negative or positive consequences of the same ACOVE-2 initiative to improve care for falls, incontinence, and cognitive impairment by measuring quality of care that was not targeted for improvement. There was no difference in change in the performance of non-targeted processes of care between intervention and control groups, suggesting neither unintended negative nor unintended positive consequences of the intervention for measured non-targeted indicators. The final section of the dissertation measures the costs and cost-effectiveness of a 6-month self-management intervention to improve glycemic control in older African-Americans and Latinos with diabetes. Intervention participants improved their hemoglobin A1c, a measure of glycemic control, by 0.4% more than control participants, at costs that were likely to be acceptable to society. The measurement methods detailed in this dissertation will serve policymakers by enabling a multidimensional assessment of the value of health services provided to individuals and groups.