The clinical and financial impact of diabetes-related interventions and policies may not be quantifiable without the use of simulation models that reflect the long-term course of disease and its complications. Models of diabetes complications are used by healthcare delivery systems and policymakers to calculate the cost-effectiveness of new tests, therapies, and policies. Most models are based on findings from the U.K. Prospective Diabetes Study, conducted in the 1980s and 1990s. These models often lack transparency and have not been updated to reflect contemporary treatments or course of diabetes, the ethnic diversity of the United States, or the importance of outcomes such as hypoglycemia. This project involves development and validation of a transparent, contemporary model of diabetes complications based on a multi-ethnic U.S. cohort (Kaiser Permanente Northern California members) that can be used by healthcare delivery systems and policymakers to guide decisions regarding optimal approaches to diabetes management.