The Monetary Policy Effect
In recent years, a good deal of research effort has been directed at the estimation of the responses of different kinds of spending to changes in monetary policy. The expenditures that are most likely to be affected by monetary policy are those financed to a substantial extent by the use of credit.
These include business investment in new plant and equipment; inventory investment; residential construction; consumer purchases of durable goods such as automobiles, electrical appliances, and furniture; and capital outlays by state and local governments. The paper by Michael J. Hamburger surveys a number of econometric studies that have been made of each of these categories of expenditures.
These studies have uncovered considerable evidence that residential construction and business investment in plant and equipment are significantly affected by monetary policy. There are also indications of significant effects on consumer purchases of durable goods and on state and local government expenditures; although less research has been directed at the responses of these sectors. There is more uncertainty about the effects of monetary policy on inventory investment.
A few studies suggest significant effects, but a number of investigators have been unsuccessful in isolating any monetary influences.
Two generalizations can be made concerning these studies. First, to the extent that monetary influences affect the various types of expenditures, the effects appear to work primarily through interest rates. Second, as was mentioned above, there are substantial time lags between changes in interest rates and the resulting changes in expenditures, although the lags seem to vary somewhat from one category of expenditures to another.
The results of this kind of investigation thus far can hardly be characterized as conclusive. In some cases, such as business investment in plant and equipment, in which a number of independent investigations have been carried out, the different investigators have used somewhat different models.
While all of the recent studies indicate that monetary policy has significant effects on investment which operate with substantial lags, both the magnitude of the effect and the length of the lag vary considerably from one study to another. Clearly, much further study will be needed before we can predict the effects of monetary policy with very much confidence.
The survey in the Hamburger paper, discussed above, relates to the initial impacts on investment-defined broadly to include not only business investment but investment by households in new homes and durable goods and capital outlays by state and local governments. In a concluding section, Hamburger discusses briefly some results obtained by computer simulations using two large econometric models of the U.S. economy.
These simulations provide estimates of the total effects on the economy of certain changes in monetary policy, including not only the initial impacts but also the secondary multiplier and accelerator effects. These simulations suggest that monetary policy has important effects but that the bulk of these effects are felt only after a considerable amount of time has elapsed following the initiation of a change in policy.