Monetarism (Friedman)

The quantity theory, sharpened

Monetarism builds on the quantity theory of money:

M × V = P × Y

where M is the money supply, V is velocity (how often a dollar changes hands per period), P is the price level, and Y is real output. The identity is uncontroversial — it always holds by accounting. Monetarism turns it into an empirical theory by adding two claims:

1. V is roughly stable in the long run, varying with technology and institutions but not with monetary policy.
2. Y is determined by real factors in the long run — capital, labor, productivity — independent of M.

Combine these and growth in M directly produces growth in P × Y, which (with stable V) is mostly inflation when Y is at its long-run path. Print money, get inflation. Don't print, don't.

The corollary is also strong: the central bank cannot permanently boost real output by printing money. Surprise injections can shift output briefly while agents are confused about whether nominal price changes are real, but the trick fades as agents learn. In the long run, money is neutral with respect to real variables.

This neutrality claim is what divided monetarism from postwar Keynesianism. Keynes had argued that monetary policy could prop up demand and cure unemployment. Friedman countered that beyond a brief horizon, monetary policy moves prices, not output.

The 1963 Monetary History

Friedman's most consequential argument wasn't theoretical — it was historical. In A Monetary History of the United States, 1867-1960 (with Anna Schwartz, 1963), he traced US monetary aggregates over nearly a century. The book ran 860 pages with extensive appendices, but its rhetorical center was Chapter 7, "The Great Contraction, 1929-1933".

The chapter laid out the data: M2 in the United States fell roughly 33% between 1929 and 1933. Banks failed in waves, depositors hoarded currency, and the Federal Reserve — newly created and structurally cautious — let the contraction run. Friedman and Schwartz argued that the Fed could have stopped it: by lending freely to solvent banks, by buying Treasury bonds, by cutting reserve requirements. Instead, it raised rates in 1931 to defend the gold standard. The Great Depression, on this telling, was a policy disaster, not a market failure.

The argument was contested for decades, but it gradually won. Ben Bernanke's 2002 speech to Friedman's 90th birthday — "Regarding the Great Depression. You're right, we did it. We're very sorry" — became the canonical Federal Reserve admission. The 2008 response, in which the Fed expanded its balance sheet aggressively rather than letting it contract, was explicitly Friedman-influenced. Bernanke later acknowledged the Monetary History as the intellectual blueprint for that response.

The Monetary History's broader impact was to put monetary aggregates at the center of macro policy and to show that the case for stable monetary growth could be made empirically, not just theoretically.

The 1970s vindication: Phillips curve breakdown

In December 1968, Friedman gave the American Economic Association presidential address that introduced the natural rate hypothesis. The argument:

1. The Phillips curve as observed in the 1950s-60s — a stable trade-off between inflation and unemployment — was an artifact of expectations adapting slowly to a generally low-inflation environment.
2. Workers and firms care about real wages. If inflation rises and they expect it to persist, nominal wages will adjust to restore real wages, eliminating the unemployment benefit.
3. So in the long run, unemployment returns to its "natural rate" — determined by search frictions, minimum wages, demographics, unionization — regardless of inflation. The long-run Phillips curve is vertical.
4. Attempts to exploit the trade-off don't just fail; they ratchet inflation higher. Each round of expansion requires a larger surprise to outpace expectations.

The 1970s tested the prediction. The US unemployment rate averaged 4.8% in the 1960s with inflation under 3%. By the late 1970s, unemployment was 7%+ and inflation 11%+. Stagflation — the simultaneous rise of both — was supposed to be impossible under the original Phillips curve. Friedman's framework predicted it precisely. The natural rate hypothesis became consensus by 1980; Phelps independently developed it the same period and shared credit.

The policy implication followed: long-run disinflation requires accepting a temporary unemployment cost (the "sacrifice ratio"), then living with the natural rate. Volcker's 1979-82 disinflation, which raised the federal funds rate above 19% and produced the worst recession since the 1930s, was the clearest application. Inflation fell from 13.5% in 1980 to 3.2% in 1983. The cost was real; so was the durable disinflation that followed.

Schools of macroeconomic thought

	Keynesian	Monetarist	New Classical	New Keynesian	MMT	Austrian
Inflation cause	Demand-pull or cost-push	Money supply growth	Money + expectations	Money + frictions	Real-resource bottlenecks	Credit expansion
Long-run Phillips curve	Sloped	Vertical (NAIRU)	Vertical	Approximately vertical	Sloped (until full employment)	Rejects the framing
Money in long run	Affects output	Neutral	Neutral	Neutral	Endogenous	Distortive
Preferred policy rule	Active stabilization	k-percent money growth	Rules over discretion	Taylor rule	Job guarantee + fiscal	Free banking / gold
Great Depression cause	Demand collapse	Fed-induced money contraction	Real shocks + policy	Mix	Insufficient fiscal response	Prior credit boom
2008 lesson	Fiscal stimulus	Aggressive QE worked	Endogenous	Forward guidance	Fiscal too small	Bailouts worsened it

Counterarguments

Velocity is not stable. The empirical foundation of monetarism was that V was predictable. Financial deregulation in the 1980s — money market funds, credit cards, electronic banking, sweep accounts — destabilized velocity. By the late 1980s, the relationship between M2 and inflation had broken down enough that the Fed abandoned monetary targets. This is widely viewed as the operational defeat of monetarism, though Friedman himself argued the right aggregate (broader than M2) would still work.

Liquidity trap. Japan after 1990 and the US/Eurozone after 2008 pushed nominal interest rates to zero with massive monetary expansion and got little inflation. Money grew dramatically; prices barely budged. Defenders argue: the relevant aggregate is the broad money supply, which grew much less than the monetary base; or that velocity collapsed in a non-monetarist way; or that the policy was simply not maintained long enough. Critics see a clean refutation.

Endogenous money. Post-Keynesian and MMT critics argue that the money supply is not exogenously controlled by central banks but emerges from credit creation in response to demand. If true, "controlling M" isn't really an option — banks create deposits when borrowers want loans, and the central bank accommodates.

Cost-push and supply shocks. The 1970s oil shocks, and the 2021-23 post-pandemic inflation, both involved supply disruptions that monetarism's pure demand-side framing handles awkwardly. Most contemporary central-bank thinking acknowledges supply-side inflation alongside monetary inflation.

Variants and successors

• K-percent rule: Friedman's original proposal — fix money growth at k%, no discretion. Tried in the late 1970s and early 1980s. Abandoned when velocity destabilized.
• NGDP level targeting: Modern variant proposed by Scott Sumner and others. Target nominal GDP at a stable growth path, allowing the central bank to use whatever instrument hits that target. Inherits monetarism's framing of money's role but drops the rigid aggregate target.
• Inflation targeting: The dominant practice since the 1990s (New Zealand 1990, then UK, Sweden, Canada, ECB, Fed by 2012). Focuses directly on inflation outcomes rather than money supply. Generally credited as the practical heir to monetarism's anti-inflation discipline.
• The Taylor rule: Sets the policy rate as a function of the inflation gap and output gap. Combines monetarist concern with inflation discipline and Keynesian concern with output stabilization. Currently the framework most central banks describe themselves as approximating.
• Helicopter money: Friedman's 1969 thought experiment for ending deflation — the central bank prints money and distributes it directly to households. Discussed seriously after 2008 and in the 2020 stimulus debate; never deployed in pure form.
• Market monetarism: A 2010s movement applying NGDP targeting and emphasizing market-implied expectations. Sumner is the public face.

Common pitfalls

• Treating M × V = P × Y as a theory. The equation is an accounting identity. Monetarism becomes a theory only when V and Y are taken as roughly independent of M.
• Conflating monetarism with austerity. Friedman supported countercyclical money creation in deep contractions (his 1969 helicopter money paper) and praised the post-2008 Fed expansion through Bernanke's reading of the Monetary History. The k-percent rule is about removing discretion, not about being passive.
• Reading "money is neutral" as "money doesn't matter". Money is neutral in the long run — but bad money policy can devastate the short run, as Friedman and Schwartz argued the Fed did from 1929-33.
• Picking the wrong monetary aggregate. Modern macro distinguishes M0, M1, M2, M3, MZM, broad credit. The correlation with inflation differs across measures and across decades. Monetarist arguments often founder on aggregate selection.
• Ignoring the credibility channel. Much of monetarism's success came not from monetary aggregates per se, but from making central banks credible inflation-fighters. Inflation expectations, not money growth alone, anchor outcomes — which is why most central banks switched to inflation targeting while keeping the monetarist diagnosis.