No one expects Landmark Medical Center in Woonsocket, RI, to suddenly shut down. Indeed a massive effort has been under way to assure its survival, in some form. The big question is what form that will be. It's a question made especially difficult by the absence of a statewide health plan. There is no consensus on which services are needed, in which locations, to best serve Rhode Islanders. Instead, the 11 acute-care hospitals compete based on their separate interests. All community hospitals in Rhode Island have been struggling financially. But Landmark is in an especially difficult position, serving many poor and elderly people with a high burden of illness. Half its revenue — an unusually high proportion — comes from the federal Medicare program for the elderly, which pays less than private insurers. Some 16% comes from the state Medicaid program for the poor, which pays even less. And for the minority of patients with private insurance, a state-sponsored study found that Landmark and other independent hospitals collect significantly lower rates than hospitals that are part of groups with clout.