Should changes in consumption be predictable?

The classical consumption models (Modigliani’s Life-Cycle hypothesis and Friedman’s Permanent Income hypothesis) tell us that consumption is dependent on life-time income. This is based on the assumptions of credit market access (so we don’t have liquidity constrained individuals) and certainty. In short this means that consumption will only change if income changes, and a temporary income change will cause consumption to rise by less (i.e. MPC is low) than a permanent income change (i.e. MPC is close to 1).

Due to the theory of consumption smoothing – whereby individuals prefer to have similar incomes over two periods (or a lifetime) than extremities in either period – we would expect change in consumption to be low over a lifetime. [...]

Search Markets

Economic theory may initially have us believe that firms shouldn’t offer a higher wage than the reservation wage of workers. If they did so then another firm could enter the market, charge below the reservation wage, have lower costs, sell output at a lower price and capture the market. Yet the theory of efficiency wage provides another story, that higher productivity can offset the cost of higher wages (so that a firm offering w>w* isn’t competed out of the market), and more importantly that a firm must offer a wage greater than the reservation wage in order to operate.