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Jennifer La’O, Ph.D.

Columbia University, New York, USA

Author: Jennifer La’O

Abstract: I construct a dynamic economy in which agents are interconnected: the output produced by one agent is the consumption good of another. I show that this economy can generate recessions which resemble traffic jams. At the micro level, each individual agent waits for his own income to increase before he increases his spending. However, his spending behavior affects the income of another agent. Thus, the spending behavior of agents during recessions resembles the stop-and-go behavior of vehicles during traffic jams. Furthermore, these traffic jam recessions are not caused by large aggregate shocks. Instead, in certain parts of the parameter space, a small pertubation or individual shock is amplified as its impact cascades from one agent to another. These dynamics eventually result in a stable recessionary equilibrium in which aggregate output, consumption, and employment remain low for many periods. Thus, much like in traffic jams, agents cannot identify any large exogenous shock that caused the recession.  Finally, I provide conditions under which these traffic jam recessions are most likely to occur.

Full Text:  “A Traffic Jam Theory of Recessions”