In the most widely analyzed type of efficiency wage model of involuntary unemployment, firms pay wages in excess of market clearing to give workers an incentive not to shirk. Such payments in excess of market clearing and the resultant equilibrium unemployment act as a worker discipline device....

This paper explains upward job mobility and observed patterns of unemployment by skill as an economy recovers from a recession. Skilled unemployment is due to rational waiting by workers looking for long-term jobs when there is a "lock-in" effect. Lock-in occurs if the conditions in the labor...