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If exchange rates are random walks, then almost everything we say about monetary policy is wrong


  • Fernando Alvarez
  • Andrew Atkeson
  • Patrick J. Kehoe


The key question asked by standard monetary models used for policy analysis is, How do changes in short-term interest rates affect the economy? All of the standard models imply that such changes in interest rates affect the economy by altering the conditional means of the macroeconomic aggregates and have no effect on the conditional variances of these aggregates. We argue that the data on exchange rates imply nearly the opposite: the observation that exchange rates are approximately random walks implies that fluctuations in interest rates are associated with nearly one-for-one changes in conditional variances and nearly no changes in conditional means. In this sense, standard monetary models capture essentially none of what is going on in the data. We thus argue that almost everything we say about monetary policy using these models is wrong.

Suggested Citation

  • Fernando Alvarez & Andrew Atkeson & Patrick J. Kehoe, 2008. "If exchange rates are random walks, then almost everything we say about monetary policy is wrong," Quarterly Review, Federal Reserve Bank of Minneapolis, issue Jul, pages 2-9.
  • Handle: RePEc:fip:fedmqr:y:2008:i:jul:p:2-9:n:v.32no.1

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    References listed on IDEAS

    1. Brandt, Michael W. & Cochrane, John H. & Santa-Clara, Pedro, 2006. "International risk sharing is better than you think, or exchange rates are too smooth," Journal of Monetary Economics, Elsevier, vol. 53(4), pages 671-698, May.
    2. Cheung, Yin-Wong & Chinn, Menzie D. & Pascual, Antonio Garcia, 2005. "Empirical exchange rate models of the nineties: Are any fit to survive?," Journal of International Money and Finance, Elsevier, vol. 24(7), pages 1150-1175, November.
    3. Meese, Richard A. & Rogoff, Kenneth, 1983. "Empirical exchange rate models of the seventies : Do they fit out of sample?," Journal of International Economics, Elsevier, vol. 14(1-2), pages 3-24, February.
    4. David K. Backus, 2001. "Affine Term Structure Models and the Forward Premium Anomaly," Journal of Finance, American Finance Association, vol. 56(1), pages 279-304, February.
    5. Fernando Alvarez & Andrew Atkeson & Patrick J. Kehoe, 2009. "Time-Varying Risk, Interest Rates, and Exchange Rates in General Equilibrium," Review of Economic Studies, Oxford University Press, vol. 76(3), pages 851-878.
    6. Fama, Eugene F., 1984. "Forward and spot exchange rates," Journal of Monetary Economics, Elsevier, vol. 14(3), pages 319-338, November.
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    Cited by:

    1. Stéphane GOUTTE & Benteng Zou, 2011. "Foreign exchange rates under Markov Regime switching model," CREA Discussion Paper Series 11-16, Center for Research in Economic Analysis, University of Luxembourg.
    2. repec:kap:iaecre:v:18:y:2012:i:3:p:299-314 is not listed on IDEAS
    3. Christopher J. Gust & David López-Salido, 2009. "Portfolio inertia and the equity premium," International Finance Discussion Papers 984, Board of Governors of the Federal Reserve System (U.S.).
    4. Stephanos Papadamou & Thomas Markopoulos, 2012. "The Monetary Approach to the Exchange Rate Determination for a “Petrocurrency”: The Case of Norwegian Krone," International Advances in Economic Research, Springer;International Atlantic Economic Society, vol. 18(3), pages 299-314, August.
    5. Granger, Clive W.J., 2012. "Useful conclusions from surprising results," Journal of Econometrics, Elsevier, vol. 169(2), pages 142-146.
    6. Heipertz, Jonas & Mihov, Ilian & Santacreu, Ana Maria, 2017. "The Exchange Rate as an Instrument of Monetary Policy," Working Papers 2017-28, Federal Reserve Bank of St. Louis.
    7. Jones, Callum & Kulish, Mariano, 2013. "Long-term interest rates, risk premia and unconventional monetary policy," Journal of Economic Dynamics and Control, Elsevier, vol. 37(12), pages 2547-2561.
    8. Carlos Eduardo Castillo-Maldonado & Fidel Pérez-Macal, 2013. "Assessment of models to forecast exchange rates: The quetzal–U.S. dollar exchange rate," Journal of Applied Economics, Universidad del CEMA, vol. 16, pages 71-99, May.
    9. Hyunjoo Ryou & Cristina Terra, 2015. "Exchange Rate Dynamics under Financial Market Frictions," THEMA Working Papers 2015-03, THEMA (THéorie Economique, Modélisation et Applications), Université de Cergy-Pontoise.
    10. A. Craig Burnside & Jeremy J. Graveline, 2012. "On the Asset Market View of Exchange Rates," NBER Working Papers 18646, National Bureau of Economic Research, Inc.
    11. Oleg Itskhoki & Dmitry Mukhin, 2017. "Exchange Rate Disconnect in General Equilibrium," NBER Working Papers 23401, National Bureau of Economic Research, Inc.
    12. Akito Matsumoto, 2011. "Global Liquidity; Availability of Funds for Safe and Risky Assets," IMF Working Papers 11/136, International Monetary Fund.


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