In the short run (and possibly in the long run), markets may find a temporary equilibrium at a price and quantity that does not correspond with the long term market clearing equilibrium. For example, in the theory of "efficiency wages", a labor market can be in equilibrium above the market-clearing wage, since each employer has the incentive to pay wages above market-clearing to motivate their employees on the job. In this case, equilibrium wages (where there is no endogenous tendency for wages to change) would not be the same as market-clearing wages (where there is no classical unemployment).