失業に関する好循環/悪循環モデル

●Kent Matthews, Patrick Minford and Ruthira Naraidoo, “Vicious and Virtuous cycles ― the political economy of unemployment in interwar UK and US”（VOX, 9 July 2008）

The main hypothesis advanced in this column is that prolonged bouts of high unemployment and low unemployment occur through a process of political economy. We argue that the structure of the economy (particularly the supply side) alters in response to shocks to the economy.

The mechanism by which demand shocks get translated into reinforcing supply-side interventions is through the political process. Shocks that cause sharp cyclical demand swings generate political reactions from public opinion and vested interest groups, which in turn influence the supply-side and therefore the natural rate of unemployment.

In this way, negative demand shocks produce reinforcing distortionary supply-side responses through an increase in the political demand for social protection. These distortions produce an equilibrium with a higher natural rate of unemployment which in turn creates a further rise in the political demand for social protection and so on until an equilibrium is reached where the bad effects are so bad that there is no further additional demand for social protection.

Similarly, a run of positive demand shocks produces a more liberal supply-side policy as people are less nervous about potential misfortune. This in turn generates a self-reinforcing political process in favour of supply-side reform and the economy moves in a virtuous circle to a low-unemployment high output equilibrium.

Richard Baldwinによる要約（＝“Luck and unemployment rates”（Free exchange, 8 July 2008））も参照のこと。