But, whatever the reason, policymakers face considerable uncertainty about the level of NAIRU. Thus, they still face a trade-off between pushing unemployment too low, and setting off an episode of inflation, and not pushing hard enough, resulting in an unnecessary waste of economic resources.
教育水平、工会和生产效率的变化可以部分解释这种不稳定性。但是，不管是出于什么原因，政策制定者还是很难寻觅到一个合适的NAIRU水平。于是，他们还是要作出权衡，即把失业率推得过低会带来一段时间的通货膨胀，而如果不过分追求低失业率，又会造成经济资源不必要的浪费。