We assessed the efficacy of materials that integrated comparative information on cost, benefits, and quality for employer-based retiree health plans and Medicare Advantage plans in a randomized experiment to test the impact of content and format. Results indicate that older consumers who received the intervention materials found the materials easier to use, gained greater knowledge about Medicare from them, were more likely to value comparative quality information, were more likely to select higher quality plans, and were more likely to choose a plan that reflected the dimensions they found most important compared to older consumers receiving the control materials.