wiki上这样讲的。

Single-payer systems may contract for healthcare services from private organizations (as is the case in Canada) or may own and employ healthcare resources and personnel (as is the case in the United Kingdom). The term single-payer thus only describes the funding mechanism—referring to health care being paid for by a single public body from a single fund—and does not specify the type of delivery, or who doctors work for. Although the fund holder is usually the government, some forms of single-payer employ a public-private system.