This document contains the testimony of Linda Blumberg before the Joint Economic Committee in September 2004. She provides her views on adverse selection in health insurance and its implications when expanding consumer choice. She emphasizes that further segmentation of risk will not improve social welfare in the US. Addressing the health care needs of all Americans and protecting access to needed services for the most vulnerable populationsthose with serious health problems and those with modest incomesrequires broad-based subsidization of both those with high medical costs and income-related protection for those unable to afford an average priced insurance policy.