The Money-Inflation Connection: It’s Baaaack!

Our St. Louis Fed colleague David Andolfatto declares it is time to bury the old saw that says when it comes to inflation, follow the money:

“One of the ideas that stuck in my head as an undergrad was the proposition that ‘inflation is always an[d] everywhere a monetary phenomenon.’ The idea is usually formalized by way of the Quantity Theory of Money (QTM)—or more precisely—the Quantity of Money Theory of the Price-Level. (QTM is not a theory of money, it is a theory of the price-level).

“In its simplest version, the QTM asserts that the equilibrium price-level is roughly proportional to the outstanding supply of money (however defined). As inflation is the rate of change in the price-level, the phenomenon of inflation is attributed primarily to excessive growth in the money supply (typically viewed as being controlled by the monetary or fiscal authority).”

Andolfatto goes on to note that the monetary base—the sum of currency in circulation and the banks’ reserve balances held at the Federal Reserve (at that page, search “reserves”)—more than doubled since fall 2008, while the rate of inflation fell.

That’s certainly true, though most versions of the quantity theory applied to monetary policy discussions lean on broader measures of money—for no better reason than those measures help the theory fit the facts. Specifically, since the 1980s the phrase “inflation is everywhere and always a monetary phenomenon” has in effect meant “inflation is everywhere and always a monetary phenomenon when we measure money by M2.”

And here’s an interesting thing. If you look at the relationship between M2 growth and core inflation over the past decade and a half, it appears that the money-inflation nexus has been gaining in strength:

Another way to see this relationship is to look at the correlation between M2 growth and core inflation over rolling 10-year windows:

Could it be that the death of the quantity theory has been greatly exaggerated?

There are plenty of reasons to be cautious. For one thing, it is oft-noted that any connection between money and inflation could be purely coincidental. In fact, if you stare hard at the picture it does appear that changes in inflation often precede changes in money growth. One interpretation is that the same factors that push trend inflation around also result in responses by policymakers or private market participants that ultimately cause the money supply to move in a sympathetic direction.

But even if causation does run from money to prices, the case is not quite solved. The monetary base measure that the Andolfatto post emphasizes has a lot to recommend itself, not least being that it is the measure of money that central banks actually control. The stark disconnect between the growth in currency and bank reserves (the quantity of which is determined by the Fed) and M2 growth (the quantity of which is determined by the decisions of banks to expand their balance sheets) raises legitimate questions about how policymakers would exploit an M2-inflation connection in an environment when the monetary base–M2 connection—the so-called “money multiplier”—has changed so dramatically.

There could be lots of answers to that question. The relatively new Federal Reserve policy of paying interest on bank reserves is one possibility. Andolfatto’s suggestion that all changes in money are not created equal might contain the germ of another explanation. For our part, we think the question is quite a bit more than academic.

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About David Altig 91 Articles

Affiliation: Federal Reserve Bank of Atlanta

Dr. David E. Altig is senior vice president and director of research at the Federal Reserve Bank of Atlanta. In addition to advising the Bank president on Monetary policy and related matters, Dr. Altig oversees the Bank's research and public affairs departments. He also serves as a member of the Bank's management and discount committees.

Dr. Altig also serves as an adjunct professor of economics in the graduate school of business at the University of Chicago and the Chinese Executive MBA program sponsored by the University of Minnesota and Lingnan College of Sun Yat-Sen University.

Prior to joining the Atlanta Fed, Dr. Altig served as vice president and associate director of research at the Federal Reserve Bank of Cleveland. He joined the Cleveland Fed in 1991 as an economist before being promoted in 1997. Before joining the Cleveland Fed, Dr. Altig was a faculty member in the department of business economics and public policy at Indiana University. He also has lectured at Ohio State University, Brown University, Case Western Reserve University, Cleveland State University, Duke University, John Carroll University, Kent State University, and the University of Iowa.

Dr. Altig's research is widely published and primarily focused on monetary and fiscal policy issues. His articles have appeared in a variety of journals including the Journal of Money, Credit, and Banking, the American Economic Review, the Journal of Economic Dynamics and Control, and the Journal of Monetary Economics. He has also served as editor for several conference volumes on a wide range of macroeconomic and monetary-economic topics.

Dr. Altig was born in Springfield, Ill., on Aug. 10, 1956. He graduated from the University of Iowa with a bachelor's degree in business administration. He earned his master's and doctoral degrees in economics from Brown University.

He and his wife Pam have four children and three grandchildren.

Visit: David Altig's Page

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