A very interesting article, in STAT News, on the need for every state to have an all-payer claims database. California policy makers are taking another look at developing an all-payer claims database. This is a large database that collects and aggregates health care claims from public and private payer sources, everyone from Medicare and Medicaid to UnitedHealth Group and Anthem. States use these databases to examine market dynamics, build consumer transparency tools, and better understand trends in health and the use of health care. About 20 states have built, or are in the process of building, all-payer claims databases. A few others, including California, have multipayer claims datasets. These often cover only a portion of the state, and never include all of its payers.