The Fundamental Surplus
指出，各种重新设计的匹配模型通过降低基本剩余份额（即无形之手可用于创造职位空缺的产出比例上限）来放大失业对生产率变动的响应，商业周期和福利国家动态均通过这一共同渠道运作。
To generate big responses of unemployment to productivity changes, researchers have reconfigured matching models in various ways: by elevating the utility of leisure, by making wages sticky, by assuming alternating-offer wage bargaining, by introducing costly acquisition of credit, by assuming fixed matching costs, or by positing government-mandated unemployment compensation and layoff costs. All of these redesigned matching models increase responses of unemployment to movements in productivity by diminishing the fundamental surplus fraction, an upper bound on the fraction of a job's output that the invisible hand can allocate to vacancy creation. Business cycles and welfare state dynamics of an entire class of reconfigured matching models all operate through this common channel.