The natural rate of unemployment is a concept of economic activity developed in particular by Milton Friedman and Edmund Phelps in the 1960s, both recipients of the Nobel prize in economics. In both cases, the development of the concept is cited as a main motivation behind the prize.It represents the hypothetical unemployment rate consistent with aggregate production being at the "long-run" level. This level is consistent with aggregate production in the absence of various temporary frictions such as incomplete price adjustment in labor and goods markets. The natural rate of unemployment therefore corresponds to the unemployment rate prevailing under a classical view of determination of activity. It is mainly determined by the economy's supply side, and hence production possibilities and e