Escalators and Elevators: A Phillips Curve for Keynesians
构建了一个理论模型，用自动扶梯和电梯的比喻解释凯恩斯经济中名义需求增长如何降低失业，而新古典经济中调整瞬时完成，政策引发的需求增长反而可能扰乱经济。
The negatively sloped long-run Phillips curve remains an issue of contention. This paper presents a theoretical model of the Phillips curve in which nominal demand growth reduces unemployment caused by stochastic shifts of demand between sectors.' The model can be understood through the following metaphor. Keynesian economies are economies in which markets adjust back to equilibrium slowly, so that nominal demand growth presents a means of speeding up the escalator process. Contrastingly, new classical economies, as set forth by e.g. Lucas (1973), are economies in which adjustment is instantaneous. Consequently, there is no role for nominal demand growth in the adjustment process, and to the extent that policy sponsored nominal demand growth is uncertain, it may actually disrupt the economy by sending the elevator to the wrong floor.