This workshop will bring together researchers from economics, sociology, medicine, epidemiology, law, and statistics, as well as public officials, to examine factors affecting the diffusion of medical technologies and to explore the implications of technology diffusion for health care quality and spending. Previous research has found wide variation across geographic regions and providers in both healthcare spending and health outcomes, but surprisingly little correlation between the two. A key hypothesis is that patterns of technology diffusion, whether for highly cost-effective treatments or less cost-effective treatments, may play an important role in the observed variation. This is an area of research which has enormous implications for understanding the determinants of quality and value in health care. Research has been advancing both in the medical community and among health economists, and this workshop will bring these streams together to explore what we know and to discuss next steps for advancing the research agenda.