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The Effects of Foreign Shocks when Interest Rates are at Zero M. Bodenstein, C. J. Erceg, L. Guerrieri. Discussion by Ricardo Mestre. Macroeconomic Modelling Workshop Jerusalem, 28-29 October 2009. Structure of presentation. Brief description of goals of paper
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The Effects of Foreign Shocks when Interest Rates are at ZeroM. Bodenstein, C. J. Erceg, L. Guerrieri Discussion by Ricardo Mestre Macroeconomic Modelling Workshop Jerusalem, 28-29 October 2009
Structure of presentation • Brief description of goals of paper • Remarks on stability properties under the ZLB • Some issues on the exercise • Some issues on the model • Great job done by authors!
Summary of paper • The paper analyses foreign demand shocks in ZLB times • Using a two-bloc DSGE model of the US & the RoW • Issue: trade spillovers with & w/o ZLB event • Conclusion: trade spillover much higher in ZLB • Why? Due to non-reaction of monetary policy
Dynamics in the ZLB • The interest rate does no longer stabilise • In most cases, the ZLB leads to multiple equilibria • Is this the case in SIGMA?
Dynamics in the ZLB • Multiple equilibria: one forward (unstable) root becomes backward (stable) root • A return to the stable region is assured in the exercise • Variables affected jump downward, then return to base • The jump is (in models of this kind) expectation-driven • Hence, importance of managing expectations • Demand shocks matter! • What about fiscal in the paper?
Solution method • The solution method seems as implemented in Troll • End point: why not long simulations? • Risks of non-linear models & steady state (Benhabib et al., 2001): deserves a comment
Monetary policy rule • Gradualism vs. activism: persistent rule may avoid the ZLB • Reasons given in paper are not convincing • How does it work? • Low rate mobility reduces the likelihood of hitting the ZLB (but worsen output, inflation) • BUT: if ZLB hit, chances are that output, inflation will worsen • Avoiding the ZLB matters! • Ergo: important to simulate with alternative γi (see previous point)
Model: price elasticity • Demand elasticity at firm level same for domestic production and exports (0.1) • Sure, demand is simpler to model, but: • Is this the evidence? • Import content of consumption and investment goods is the same: • Again, is this the best empirical choice?
Model: pricing mechanisms • Model is symmetric LCP • What about asymmetric PCP(US)/LPC(RoW)? • US exporters are PCP: higher impact on exports • RoW exporters are LPC: less transmission to US imports & US prices • Isn’t this the empirically relevant setup?
Minor points • Why using inot in the rule? • Justification seems weak: • Little extra delay in exiting the ZLB • Use of inot implies odd kind of policy! • Why are spillovers not returning to non-ZLB case when the ZLB does not bind?