景気循環ABC


集計すると見えなくなってしまう何かを掴もうとして、一次元経済学*1に抗おうとして、書かれた力作に連想して、何度も読み返す僕の枕元から引用したいと思った。


Business Cycles and Equilibrium

Business Cycles and Equilibrium

In my theory, business cycles are caused in part by shifting tastes and shifting technology--by shifting demand and supply curves. Labor markets provide the simplest example. When demand for shoe machine operators declines and demand for computer operators rises, people will shift out of the first group and into the second. Some people will shift directly, but most of the shifts will be indirect. The people who leave shoe machinery will not be the same as those who go into computers. Some people will shift without a break in employment, but some will be unemployed between jobs. The more shifting there is, the more unemployment there will be.


If the world were static, people would settle into their jobs, and employers would learn about their skills. There would be no reason for employees to want to change jobs and no reason for employers to want them to change. But there are continual changes in people's tastes for consumer goods and services and constant changes in the economy's ability to supple various combinations of goods and services.


Business cycle peak occur when there is a good match between the types of skills wanted and the types of skills available or between the types of physical capital wanted and the types of physical capital available. Business cycle troughs occur when there is a poor match between wants and skills. The peaks and troughs occur within a path that is itself subject to random influences; new discoveries may shift an economy onto a higher path, while bad weather or war may shift it onto a lower path. These random influences are not always large, either; an accumulation of small shocks will have the same impact as one large shock.


A mismatch will occur when investments in physical or human capital do not pay off as expected or when actual wants turn out to differ from expected wants. Something as simple as the decision to produce a new toy is the raw material of the business cycle. If demand for the toy turns out to be high, or if production cost turn out to be low, that will be good for economy. If demand for the toy turns out to be low, or if production cost turn out to be high, that will be bad for the economy. The accumulation of these correct and incorrect decisions creates the business cycle. In this sense, the business cycle is due to errors--errors in forecasting tastes or errors in forecasting technology. But these are unavoidable errors; the investment decisions made are the best ones possible in the light of the information available when they made.


Unemployment is voluntary in the sense that it is a shift from a low-wage sector to a higher wage sector. It's involuntary in the sense that many people making this shift will wish they had made investments earlier that would have put them into higher wage sectors. But at the time they made them, their investments were correct.


Unemployment is not just job search. People who have been laid off and waiting for recall are also counted as unemployed. They are unemployed because they are worth less to their employers now than they probably will be in the future. They are not willing to work at a wage that would be low enough to induce employers to keep them on the job.


Inflation normally plays no role in this theory. The correct or incorrect allocation of skills to sectors can occur at any rate of inflation. Rapid advances (or retreats) in technology (or tastes) can occur at any rate of inflation. The one exception is when inflation turns negative--when it turns to substantial deflation, as it did in the 1930s. Substantial deflation can make things worse.

https://www.jstor.org/stable/4478501


もちろん（一般均衡とは言い難いが）埋蔵金を貯め込んだ中央銀行が、永遠には続けようもない低利誘導を繰り出せば、ブラックの世界にも一時的な影響を与えることになる。それらは、どのようなものか。僕らはきっと、体験を通じて、よく知っているはずだ。

*1:http://d.hatena.ne.jp/equilibrista/20151220/p1