Although the National Committee for Quality Assurance (NCQA) has been measuring health plan quality for more than a decade, consistent measures of cost have only recently been developed. In 2006, NCQA introduced new measures of health care resource utilization for six chronic conditions treated in various care settings. This project will look at more than 500 health plans to examine the relationship between the new cost measures and quality of care, as well as patients' experiences. The investigators will identify the factors associated with high performance, using existing data sources as well as new survey data on plan characteristics and operational processes. In addition, the project team will conduct case studies of five plans to explore additional factors that may contribute to high performance. NCQA is providing in-kind support for the project.