Nearly 20 years ago, health economist Henry Aaron characterized the US health care system as “an administrative monstrosity, a truly bizarre mélange of thousands of payers with payment systems that differ for no socially beneficial reason, as well as staggeringly complex public systems with mind-boggling administered prices and other rules expressing distinctions that can only be regarded as weird.”^1(p801) However, Aaron insisted, our weird system exists for a well-understood set of political reasons, “including a pervasive popular distrust of centralized authority, a federalist governmental structure, insistence on individual choice (even when, as it appears to me, choice sometimes yields no demonstrable benefit), the continuing and unabated power of large economic interests, and the virtual impossibility of radically restructuring the nation’s largest industry.”^1(p802) We do not get radical restructurings in the United States. Instead, we get incremental changes. Sometimes these incremental changes have the effect that their proponents intended. At other times, they have unintended and surprising consequences. Sometimes they have both. Often, it is hard to figure out the specific effects of specific policy changes.

将近20年前，卫生经济学家亨利·亚伦（Henry Aaron）将美国卫生保健系统定性为“行政怪兽，成千上万的付款人的真正怪异混合物，其付款系统没有任何对社会有益的原因而有所不同，以及令人震惊的复杂公共系统，令人费解的管理价格和其他规则，这些差异只能被视为怪异的。” ^{1 （p801）}然而，亚伦坚持认为，我们的怪异制度之所以存在，是出于一系列政治上容易理解的政治原因，“包括普遍对中央集权机构的不信任，联邦制政府结构，坚持个人选择（即使在我看来，有时候不会产生明显的利益），巨大的经济利益持续不断且不受削弱的力量，以及根本不可能对美国最大的产业进行彻底重组的事实。” ^{1 （p802）}我们在美国没有进行根本性的重组。相反，我们得到了增量更改。有时，这些增量更改会产生其支持者想要的效果。在其他时候，它们会带来意想不到的后果。有时他们两者都有。通常，很难弄清具体政策变化的具体影响。