How has the Northwest Region of Kaiser Permanente (KPNW) continued to offer both a standard M+C option with limited prescription drug coverage and a Social HMO (SHMO) after more than 18 years? The researchers studied how KPNW markets the options to beneficiaries, as well as whether there is evidence of adverse selection between the two options based on enrollee characteristics and acute care utilization. The researchers also analyzed how expanded care has been financed, what it has cost and how services and case management have been used. The objective of the study was to inform the debate about how to serve chronically ill and disabled Medicare beneficiaries within managed care arrangements.