His research is focused on understanding the value and quality of care delivered to vulnerable populations with an emphasis on the role of the informal and formal long-term care system. To that end, he has prospectively and retrospectively evaluated the cost-effectiveness of nondrug interventions aimed at helping older adults and caregivers. In addition, he has evaluated the effect of dementia on Medicare expenditures, he has conducted systematic reviews on the quality and effectiveness of interventions to prevent cognitive decline, and he has developed a novel microsimulation that predicts dementia progression and associated costs.