Laurence M. Ball (2009), "Hysteresis in Unemployment: Old and New Evidence" (Cambridge, MA: NBER Working Paper No. 14818, March):
Abstract: This paper argues that hysteresis helps explain the long-run behavior of unemployment. The natural rate of unemployment is influenced by the path of actual unemployment, and hence by shifts in aggregate demand. I review past evidence for hysteresis effects and present new evidence for 20 developed countries. A central finding is that large increases in the natural rate are associated with disinflations, and large decreases with run-ups in inflation. These facts are consistent with hysteresis theories and inconsistent with theories in which the natural rate is independent of aggregate demand.