The question of what caused the Great Depression - and, separately, why it lasted as long as it did - remains one of the most contested in economic history. Despite roughly a century of subsequent scholarship, economists and historians have not converged on a single accepted account. The dispute is not merely about emphasis; competing schools disagree about basic causal mechanics, about whether the 1920s boom was itself unsustainable, about whether the Federal Reserve's errors were errors of omission or commission, and about whether government intervention in the 1930s shortened or lengthened the contraction. The disagreement is sharpened by the fact that the period serves as a proving ground for rival schools of macroeconomics more broadly, so interpretations of the 1929-1941 episode tend to track, and reinforce, prior theoretical commitments.

This article presents the major competing explanations as their proponents argue them, without adjudicating between them. See great-depression-new-deal-recovery-mechanisms-debate for the related dispute over whether New Deal policies hastened or delayed recovery, and great-depression-new-deal-revisionist-economics-viewpoint for one specific revisionist account of New Deal effects.

The monetarist account, most fully developed by Milton Friedman and Anna Schwartz in *A Monetary History of the United States, 1867-1960* (1963), holds that the Great Depression was caused, and its severity determined, by a collapse in the money supply that the Federal Reserve had the power to prevent and failed to exercise. Proponents of this view argue that the initial 1929 downturn was unremarkable by the standards of prior American business cycles, and that what converted an ordinary recession into a decade-long catastrophe was a sequence of policy failures at the Fed: a tightening of monetary policy beginning in 1928 to curb stock market speculation, the failure to act as lender of last resort during the banking panics of 1930-1933, and a passive acceptance of a roughly one-third contraction in the money stock between 1929 and 1933. Advocates of this view point to the failure of the Bank of the United States in December 1930 - which Friedman characterized as a solvent institution brought down by a self-justifying run - as a turning point that the Fed could have arrested through liquidity injections but did not. On this account, the Fed's passivity reflected institutional confusion following the 1928 death of Benjamin Strong, the New York Fed governor who had previously provided de facto leadership, combined with a misplaced “liquidationist” doctrine, associated with Treasury Secretary Andrew Mellon, holding that allowing weak banks and firms to fail was a necessary precondition for recovery. Under this view, sound monetary policy was both necessary and sufficient to have prevented the Depression's severity, and the episode is read as a demonstration of the dangers of discretionary central banking rather than of any inherent instability in market economies. See Great Depression - Monetarist Viewpoint.

The Austrian school, developed most extensively for this period by Murray Rothbard in *America's Great Depression* (1963) drawing on the business cycle theory of Ludwig von Mises and Friedrich Hayek, locates the cause of the Depression not in the Fed's actions after 1929 but in its actions during the preceding boom. On this account, the Federal Reserve's expansion of bank credit during the 1920s - interest rates held below their natural market level - financed an unsustainable pattern of investment, distorting the allocation of capital between current consumption and long-term production in ways that could not be sustained once the artificial credit expansion stopped. The resulting recession is understood not as a malfunction to be reversed but as a necessary liquidation: the market's mechanism, on this account, for correcting the malinvestments and reallocating the resources that proponents argue were misdirected during the boom back to economically viable uses. Proponents of this view argue that the severity and length of the Depression resulted from interventions - by the Federal Reserve, the Hoover administration, and later the New Deal - that prevented prices, wages, and capital structures from adjusting, thereby prolonging the liquidation that would otherwise have been comparatively brief. Where the monetarist account treats the Fed's error as one of excessive passivity after 1929, the Austrian account treats the more consequential error as excessive activism before it. See Great Depression - Austrian Viewpoint.

The Keynesian account, developed contemporaneously by John Maynard Keynes in *The General Theory of Employment, Interest and Money* (1936) and later elaborated by economic historians including Peter Temin, holds that the Depression resulted from an autonomous collapse in aggregate demand - a falloff in consumption and especially investment spending - that a market economy lacked any automatic mechanism to correct. On this view, the 1929 stock market crash destroyed household wealth and confidence, while over-leveraged installment buying, an already-fragile agricultural sector, and income inequality that had concentrated purchasing power among savers rather than spenders left consumption demand exceptionally vulnerable to a shock. Proponents argue that wages and prices did not fall quickly enough, or far enough, to clear markets, particularly because nominal wage rigidity prevented the labor market from adjusting, so that the contraction in spending translated directly into unemployment rather than being absorbed by falling prices. Where monetarists treat the money supply collapse as the central causal variable, Keynesians within this tradition generally treat it as one channel among several through which a prior collapse in demand and confidence was transmitted and amplified, and argue that fiscal policy - government spending sufficient to substitute for the missing private demand - was the necessary corrective tool, a role monetary policy alone could not fill once interest rates approached their lower bound. See Great Depression - Keynesian Viewpoint.

Irving Fisher's debt-deflation theory, formulated in the 1930s and later extended by Ben Bernanke (1995) under the label of the “financial accelerator,” argues that the Depression's severity is best explained by the interaction between high levels of nominal debt accumulated during the 1920s and the unanticipated deflation that followed the 1929 crash. On this account, falling prices increased the real burden of debts fixed in nominal terms, forcing distressed selling of assets and inventory by debtors attempting to maintain solvency, which in turn drove prices down further, increasing real debt burdens still more in a self-reinforcing spiral. Proponents argue that this mechanism operated independently of, and in addition to, the contraction in the money supply emphasized by monetarists: even holding monetary policy fixed, an economy that entered the crash heavily leveraged would experience deeper and more protracted distress than one that had not, because bank and firm balance sheets - not merely the aggregate money stock - transmitted and amplified the shock to the real economy. This view is frequently paired with an emphasis on the credit-market disruptions caused by the wave of bank failures themselves, treated as a distinct channel of harm beyond their effect on the money supply.

A body of work most associated with Barry Eichengreen, particularly *Golden Fetters* (1992), and with Ben Bernanke's research on the international transmission of the Depression, argues that the central cause was the structure of the interwar gold standard itself, and that the Depression cannot be understood as a primarily domestic American event. On this account, countries that adhered most rigidly to gold, and for the longest period, suffered the deepest and most prolonged contractions, while countries that abandoned the gold standard earlier - Britain in 1931, the United States in 1933 - recovered correspondingly sooner, a correlation proponents argue is too consistent across countries to be coincidental. Adherents of this view emphasize that the gold standard forced contractionary monetary policy on countries simultaneously and synchronously, transmitting deflationary pressure across borders regardless of each country's individual circumstances, and that France's accumulation of gold reserves beginning in 1927 placed deflationary pressure on the rest of the gold-linked world independent of any single central bank's domestic errors. On this account, the Federal Reserve's tightening cannot be evaluated in isolation from the international monetary architecture that constrained its choices, and the proper unit of analysis is the gold standard as a system rather than the policy decisions of any one central bank.

A more recent body of work, associated with economists including Harold Cole and Lee Ohanian, argues that while monetary contraction may explain the initial 1929-1933 downturn, it cannot account for the failure of the economy to recover fully through the remainder of the 1930s, and that this latter puzzle requires a separate explanation centered on labor markets and policy. On this account, New Deal-era policies - including the National Industrial Recovery Act's encouragement of industry cartels and above-market wages, and later labor legislation strengthening collective bargaining - kept real wages elevated above market-clearing levels and suppressed the competitive pressure that would otherwise have restored employment, producing a decade of suppressed output even as the monetary contraction itself was being reversed. Proponents of this view treat the 1937-38 recession within the Depression as evidence that contractionary forces persisted independent of monetary policy, since that downturn followed years of monetary expansion. This explanation focuses less on the origin of the initial contraction, on which its proponents are frequently agnostic, and more on explaining the unusual depth and duration of the subsequent stagnation. See great-depression-new-deal-revisionist-economics-viewpoint.

Despite substantial disagreement over root causes and the appropriate corrective response, most participants in this debate agree on several empirical points: that the money supply contracted by roughly one-third between 1929 and 1933; that approximately one-fifth of American commercial banks failed during the contraction; that nominal and real wages did not fall in a manner that cleared labor markets, resulting in sustained high unemployment rather than rapid price adjustment; and that the Depression was a genuinely international phenomenon affecting most countries on the gold standard, even where its severity and timing varied. There is also broad, though not universal, agreement that the 1928 tightening of Federal Reserve policy in response to stock market speculation played some contributing role in the initial downturn, even among scholars who assign it secondary rather than primary causal weight.

• Great Depression
• Great Depression - History
• Great Depression - Monetarist Viewpoint
• Great Depression - Austrian Viewpoint
• Great Depression - Keynesian Viewpoint
• great-depression-new-deal-recovery-mechanisms-debate
• great-depression-new-deal-revisionist-economics-viewpoint

1. Milton Friedman and Anna Jacobson Schwartz, *A Monetary History of the United States, 1867-1960* (Princeton, NJ: Princeton University Press, 1963).
2. Ben S. Bernanke, “Money, Gold, and the Great Depression” (H. Parker Willis Lecture in Economic Policy, Washington and Lee University, Lexington, VA, March 2, 2004), Federal Reserve Board, Washington, DC.
3. Murray N. Rothbard, *America's Great Depression*, 5th ed. (Auburn, AL: Ludwig von Mises Institute, [1963] 2000).
4. John Maynard Keynes, *The General Theory of Employment, Interest and Money* (London: Macmillan, 1936).
5. Peter Temin, *Did Monetary Forces Cause the Great Depression?* (New York: W. W. Norton, 1976).
6. Irving Fisher, “The Debt-Deflation Theory of Great Depressions,” *Econometrica* 1, no. 4 (1933): 337-357.
7. Ben S. Bernanke, “The Macroeconomics of the Great Depression: A Comparative Approach,” *Journal of Money, Credit and Banking* 27, no. 1 (1995): 1-28.
8. Barry Eichengreen, *Golden Fetters: The Gold Standard and the Great Depression, 1919-1939* (New York: Oxford University Press, 1992).
9. Harold L. Cole and Lee E. Ohanian, “New Deal Policies and the Persistence of the Great Depression: A General Equilibrium Analysis,” *Journal of Political Economy* 112, no. 4 (2004): 779-816.
10. Lee E. Ohanian and John B. Taylor, *Government Policies and the Delayed Economic Recovery* (Stanford, CA: Hoover Institution Press, 2012).