This study is designed to answer two research questions: (I) How do Medicare beneficiaries use comparative quality information when choosing a health plan? and (2) Does providing comparative quality information affect Medicare beneficiaries' choice of health plan? Cognitive interviews utilizing a concurrent, think aloud approach will be conducted with a sample of Medicare beneficiaries to answer the first research question. Subjects will be asked to imagine that they are choosing a health plan for themselves using cost, benefit and quality information provided to them by the Medicare program. To answer the second research question, a laboratory experiment with a sample of Medicare beneficiaries will be conducted. Subjects, who will be randomly assigned to either a control group or treatment groups, will be asked to imagine that they are choosing a health plan for themselves. The control group will receive cost and benefit information only while the treatment groups will receive cost, benefit and quality information. Subjects will choose one of three fictitious health plans and complete a questionnaire. Logistic and multinomial logistic regression will be utilized to determine the effects of providing comparative quality information on Medicare beneficiaries' health plan choices. Both understanding how Medicare beneficiaries use various types of information when choosing a health plan and determining whether comparative quality information affects their health plan choices, can help guide the development and improvement of comparative quality information for them. Ultimately, this research may benefit Medicare beneficiaries if it leads to the development and dissemination of effective information that helps them choose plans that best meet their needs.