3  See, for example, Paul R. Krugman, “It’s Baaack: Japan’s Slump and the Return of the Liquidity Trap,” Brookings Papers on Economic Activity, 1998 (2); 137–205; David Reifschneider and John C. Williams, ‘‘Three Lessons for Monetary Policy in a Low-Inflation Era,’’ Journal of Money, Credit and Banking, 32 (4) Part 2, 2000: 936–66; Gauti B. Eggertsson and Michael Woodford, “The Zero Bound on Interest Rates and Optimal Monetary Policy,” Brookings Papers on Economic Activity, 2003 (1); 139–211; and Michael Woodford, “Methods of Policy Accommodation at the Interest-Rate Lower Bound,” Speech delivered at the 2012 Economic Policy Symposium, Federal Reserve Bank of Kansas City, 2012.
4  BIS central bankers’ speeches  Open-ended, calendar-based, and state-contingent forward guidance Forward guidance can take various forms. For example, it can be applied solely to the policy interest rate or to a broader set of monetary stimulus measures including the policy rate and asset purchases. It can be categorized as open-ended, calendar-based, or state-contingent (or threshold-based).