Natural rate of unemployment is the lowest rate of unemployment that an economy can sustain over the long run. Keynesians believe that a government can lower the rate of unemployment (i.e. employ more people) if it were willing to accept a higher level of inflation (the idea behind the Phillips Curve). However, critics of this say that the effect is temporary and that unemployment would bounce back up but inflation would stay high. Thus, the natural, or equilibrium, rate is the lowest level of unemployment at which inflation remains stable. Also known as the "non-accelerating inflation rate of unemployment" (NAIRU). When the economy is said to be at full employment, it is at its natural rate of unemployment. Economists debate how the natural rate might change. For example, some economists think that increasing labor-market flexibility will reduce the natural rate. Other economists dispute the existence of a natural rate altogether.
[Source:
http://www.investopedia.com/terms/n/naturalunemployment.asp]
Sayed Farrukh Ahmed
Assistant Professor
Faculty of Business & Economics
Daffodil International University
