John Williams recently gave a speech on teaching about monetary theory and policy after the financial crisis. Here is the basic thesis:
When I was an undergraduate at Berkeley in the early 1980s, much of the monetary economics that I learned was based on theories from the 1950s or even earlier. These included the quantity theory of money, Keynes’s LM curve, Milton Friedman’s monetarism, and the Baumol-Tobin theory of money demand, to name a few examples. Now, there’s no question that Keynes, Friedman, and Tobin were among the greatest monetary theorists of all time. Their theories are elegant statements of fundamental economic principles. As such, they deserve to be taught for a long time to come. But viewing them as definitive in today’s world is like thinking that rock and roll stopped with Elvis Presley. The evolution of money and banking since the 1950s is at least as dramatic as what’s happened with popular music—not that I want to compare the Fed with Lady Gaga. The theories of that era need to be adapted to the brave new world in which we now live.
I am not sure what this means, however, given the remainder of the speech. Despite the fact that Williams claims that the work of Friedman, Tobin, and Keynes represent “elegant statements of fundamental economic principles”, he subsequently goes on in the speech to largely disparage this work; in particular, the quantity theory of money and the Baumol-Tobin inventory-theoretic model of money demand. While I share Williams view that we need to understand modern innovations in economic thinking, I also think that it is important to understand and appreciate contributions of the likes of Friedman, Tobin, Keynes, and others. There is much that we can learn from the history of economic thought and, in this respect, it is important to read primary sources of the literature and not second-hand accounts (note: this is a general statement, not a knock against Williams). Thus, while I share Williams’ view that we need to appreciate recent contributions, I think that it is important to give fair treatment to earlier important contributions as well. I will elucidate this point below.
Williams seems to disparage the quantity theory of money by pointing to a fairly standard objection:
There have been a number of attempts to find a broader measure of “money” that has a stable relationship with nominal spending — that is, a constant velocity.
He then proceeds to detail differences in different monetary aggregates and their growth rates during the crisis. Differing growth rates and changes in velocity over the past few decades are then cited as evidence that using using the money supply to forecast nominal spending or inflation is a fool’s errand. This reasoning is flawed for two reasons. First, constant velocity is a straw man as Thomas Sowell details in On Classical Economics:
The idea that the price level is rigidly linked to the quantity of money by a velocity of circulation which remains constant through all transitional adjustment processes cannot be found in any classical, neoclassical, or modern proponent of the quantity theory of money. Changes in the velocity of circulation — short run and/or long run — were analyzed by David Hume, Adam Smith, Henry Thornton, T.R. Malthus, David Ricardo, Nassau Senior, John Stuart Mill, Alfred Marshall, Knut Wicksell, Irving Fisher, and Milton Friedman.
As I have illustrated before, velocity is not constant, but appears to be a stable function of the interest rate. (See Allan Meltzer’s graph.)
The second flaw in the analysis is that Williams is relying on simple sum aggregates, which are theoretically flawed and often produce puzzling empirical results. The question surrounding the quantity theory of money is essentially whether or not money can forecast inflation and nominal income growth and the answer is yes especially using longer time horizons and low frequency data.
Williams similarly caricatures analysis of the money multiplier:
The breakdown of the standard money multiplier has been especially pronounced during the crisis and recession. Banks typically have a very large incentive to put excess reserves to work by lending them out.
I assume that what Williams means by “the standard money multiplier” is the framework put forward in Phillips’ (1920) Bank Credit in which the money multiplier is a parameter. This view of the multiplier might be taught in principles, but I don’t think that it is used beyond that point. Even in Mishkin’s Money and Banking text, which does include analysis of the multiplier, there are explicit references to changes in the underlying factors that determine such a multiplier. Indeed, the literature on monetary theory has long recognized that the money multiplier could not be viewed as fixed coefficient. In the post-war era, this view was recognized by Gurley and Shaw (1960) and Tobin (1963). In addition, Brunner and Meltzer (e.g. JPE, 1968; JPE, 1972) explicitly modeled the money multiplier as a function of interest rates.
Jurg Niehans (1978: 274) elaborates on the points above:
While this fixed-coefficient approach, though perhaps pedestrian, is often useful and , for certain purposed, illuminating, it is also subject to serious limitations. Taken at face value it seems to say that money is very different from other things, inasmuch as demand has no influence on the quantity available; the quantity seems to be purely supply-determined. However, this is a superficial impression. It is well recognized that the coefficients appearing in the multiplier are not, in fact, technological constants, but depend, in turn, on interest rates (Brunner and Meltzer, 1968).
In addition, as Niehans (1978: 274) details, the general equilibrium approach in which interest rates are jointly determined with the money supply was developed by Tobin (1963), but actually has “its long ancestry in the pre-Phillips tradition of money supply theory.” Those who have used the money multiplier in discussions of the crisis have, by and large, recognized these points as well.
Like Williams, I agree that the financial crisis and the broader recession pose important questions for monetary theorists and teachers. However, I believe that there is much to be learned in both the present literature and the past literature on issues of monetary analysis and central banking (see Perry Mehrling’s The New Lombard Street, for example). And I wish that Tobin and Friedman would have received fairer treatment from Williams.