Phillip David Cagan (April 30, 1927 – June 15, 2012) was an American scholar and author. He was Professor of Economics Emeritus at Columbia University.

Born in Seattle, Washington, Cagan and his family moved to Southern California shortly thereafter. Cagan joined the U.S. Navy at age 17 and fought in World War II. After the war, Cagan decided to go to college, and earned his B.A. from UCLA in 1948. Cagan received his M.A. in 1951, and his Ph.D. in Economics in 1954 from the University of Chicago.^[2]

After graduate school, Cagan joined the National Bureau of Economic Research (NBER) in New York City where he worked for two years. Then Cagan re-entered academia, teaching at the University of Chicago for three years, and at Brown University for seven years. In 1966 Cagan was hired by Columbia University, where he taught economics for nearly thirty years — save for fifteen months spent in Washington, D.C., when he was on the staff of the Council of Economic Advisors (CEA).

During his time at Columbia, Cagan was also associated with the American Enterprise Institute (AEI) in Washington, D.C., writing on public policy issues.

Cagan lived in Palo Alto, California during his last years.

Cagan's work focused on monetary policy and the control of inflation. Cagan has published over 100 books, journal articles, reviews, reports, and pamphlets on these and other topics in macroeconomics. He is perhaps best known for Determinants and Effects of Changes in the Stock of Money, 1875–1960, a work that sought to identify the "causal relationships between changes in money, prices and output."^[3] The book, part of the NBER series that contained Milton Friedman and Anna J. Schwartz's Monetary History of the United States, 1867–1960, was praised for its "careful empirical work" and called "the most complete study in the area."^[4]

Cagan's most important contribution to economics, however, is the article included in Milton Friedman's edited volume Studies in the Quantity Theory of Money (1956), entitled "The Monetary Dynamics of Hyperinflation,"^[5] a work that became an "instant classic" in the field.^[2]

The article, which contained "extensive manipulation of differential equations and an ingenious use of exponentially weighted averages",^[6] analyzed seven hyperinflations and found that "the parameters of money demand functions estimated during hyperinflation generally satisfy the condition of dynamic stability that precludes the inflation from being self-generating, or displaying period-to-period oscillations."^[7]

After its publication, Cagan's article generated a significant body of work, as a number of leading macroeconomists either reexamined or extended Cagan's model, most notably "Barro (1970), Sargent and Wallace (1973), Frenkel (1975, 1976a, 1976b, 1977, 1979), Sargent (1977), Abel et al. (1979), Salemi (1979), and Salemi and Sargent (1979)."^[8] In addition, monetary economists today often refer to a "Cagan demand function" when modeling the real value of money.^[9][10]

Because of the impact that this groundbreaking work had upon the economics profession, Cagan was elected Fellow of the Econometric Society (the most prestigious society in the field),^[11] and was mentioned as a possible candidate for the Nobel Prize in Economics.^[12] However, following his death in 2012, he is no longer eligible for a Nobel Prize.

• Cagan, Phillip (1956). "The Monetary Dynamics of Hyperinflation". In Friedman, Milton (ed.). Studies in the Quantity Theory of Money. Chicago: University of Chicago Press. ISBN 0-226-26406-8..
• ______, "Why Do We Use Money in Open Market Operations?" The Journal of Political Economy, Vol. 66, No. 1 (Feb., 1958), pp. 34–46. [1]
• ______, "The Demand for Currency Relative to the Total Money Supply," The Journal of Political Economy, Vol. 66, No. 4 (Aug., 1958), pp. 303–328, [2]
• ______, Determinants and Effects of Changes in the Stock of Money, 1875–1960, New York: Columbia University Press (1965).[3]
• ______, "The Non-Neutrality of Money In the Long Run: A Discussion of the Critical Assumptions and Some Evidence," Journal of Money, Credit and Banking, Vol. 1, No. 2, Conference on Money and Economic Growth (May, 1969), pp. 207–227. [4]
• ______, Persistent Inflation: Historical and Policy Essays, New York: Columbia University Press (1979).[5]
• ______, "Reflections on Rational Expectations," Journal of Money, Credit and Banking, Vol. 12, No. 4, Part 2: Rational Expectations (Nov., 1980), pp. 826–832. [6]
• ______, "The Choice Among Monetary Aggregates as Targets and Guides for Monetary Policy," Journal of Money, Credit and Banking, Vol. 14, No. 4, Part 2: The Conduct of U.S. Monetary Policy (Nov., 1982), pp. 661–686. [7]
• ______, "Does Endogeneity of the Money Supply Disprove Monetary Effects on Economic Activity?" Journal of Macroeconomics, Vol. 15, (Summer 1993).
• Phillip Cagan and William G. Dewald, "The Conduct of U.S. Monetary Policy: Introduction," Journal of Money, Credit and Banking, Vol. 14, No. 4, Part 2: The Conduct of U.S. Monetary Policy (Nov., 1982), pp. 565–574. [8]
• Phillip Cagan and Arthur Gandolfi, "The Lag in Monetary Policy as Implied by the Time Pattern of Monetary Effects on Interest Rates," The American Economic Review, Vol. 59, No. 2, Papers and Proceedings of the Eighty-first Annual Meeting of the American Economic Association (May, 1969), pp. 277–284 [9]
• Phillip Cagan and Anna J. Schwartz, "Has the Growth of Money Substitutes Hindered Monetary Policy?" Journal of Money, Credit and Banking, Vol. 7, No. 2 (May, 1975), pp. 137–159. [10]
• ______, "The National Bank Note Puzzle Reinterpreted," Journal of Money, Credit and Banking, Vol. 23, No. 3, Part 1 (Aug., 1991), pp. 293–307. [11]

• Monetarism

• Van Overtveldt, Johan (2007). The Chicago School: How the University of Chicago Assembled the Thinkers Who Revolutionized Economics and Business. Chicago: Agate Publishing. ISBN 978-1-932841-14-5.
• Snowdon, Brian; Vane, Howard R., eds. (2002). "Phillip Cagan". An Encyclopedia of Macroeconomics. Cheltenham, UK: Edward Elgar Publishing. p. 105..
• Engsted, Tom (1993). "Cointegration and Cagan's Model of Hyperinflation under Rational Expectations". Journal of Money, Credit and Banking. 25 (3). Blackwell Publishing: 350–360. doi:10.2307/2077767. JSTOR 2077767.
• Salemi, Michael K.; Thomas J. Sargent (1979). "The Demand for Money During Hyperinflation under Rational Expectations: II". International Economic Review. 20 (3). Blackwell Publishing: 741–758. doi:10.2307/2526270. JSTOR 2526270.
• Frenkel, Jacob A. (1977). "The Forward Exchange Rate, Expectations, and the Demand for Money: The German Hyperinflation". International Economic Review. 67 (4): 653–670. ISSN 0002-8282. JSTOR 1813397.
• Sargent, Thomas J. (1977). "The Demand for Money During Hyperinflation under Rational Expectations: I". International Economic Review. 18 (1). Blackwell Publishing: 59–82. doi:10.2307/2525769. JSTOR 2525769.
• Sargent, Thomas J.; Neil Wallace (1973). "Rational Expectations and the Dynamics of Hyperinflation". International Economic Review. 14 (2). Blackwell Publishing: 328–350. doi:10.2307/2525924. JSTOR 2525924. S2CID 153883996.
• Hu, Teh-wei (1971). "Hyperinflation and the Dynamics of the Demand for Money in China, 1945–1949". Journal of Political Economy. 79 (1): 186–195. doi:10.1086/259733. JSTOR 1837395. S2CID 153790758.
• Barro, Robert J. (1970). "Inflation, the Payments Period, and the Demand for Money" (PDF). The Journal of Political Economy. 78 (6): 1228–1263. doi:10.1086/259707. JSTOR 1830622. S2CID 67760257.

• Faculty Emeriti, Department of Economics, Columbia University
• Major works of Phillip Cagan, New School's CEPA Website
• Overview of Monetarism, New School's CEPA Website
• Thayer Watkins, "Episodes of Hyperinflation," Archived 2012-12-07 at the Wayback Machine San José State University Department of Economics