Grimaud, A., Salle, I., & Vermandel, G. (2024). A Dynare Toolbox for Social Learning Expectations. Journal of Economic Dynamics and Control,104984
Social learning (SL) is a behavioral model in which expectations and the resulting aggregate dynamics stem from the interactions of a large amount of heterogeneous agents. Nonetheless, this framework has so far lacked micro-foundations and a general-solution method. This paper bridges these two gaps with: (i) a micro-founded New Keynesian model with social learning expectations; (ii) a general solution method that we implement in a Dynare toolbox that solves any linear state-space model with SL expectations. The resulting framework provides a self-contained tool to contrast policy analysis under SL and rational expectations. As an illustration, optimal monetary policy rules are studied under the two expectation regimes.
Arifovic, J., Grimaud, A., Salle, I., & Vermandel, G. (2025), Social Learning and Monetary Policy at the Effective Lower Bound. Journal of Money, Credit and Banking, 57: 439-475.
This paper develops a model that jointly accounts for the missing disinflation in the wake of the Great Recession and the subsequently observed inflation-less recovery. The key mechanism works through heterogeneous expectations that may durably lose their anchoring to the central bank (CB)'s target and coordinate on particularly persistent below-target paths. The welfare cost associated with persistent low inflation may be reduced if the CB announces to the agents its target or its own inflation forecasts, as communication helps coordinate expectations. However, the CB may lose its credibility whenever its announcements become decoupled from actual inflation.
Gasteiger, E., & Grimaud, A. (2023). Price setting frequency and the Phillips Curve. European Economic Review, 104535.
We develop a New Keynesian (NK) model with endogenous price setting frequency. Whether a firm updates its price is a discrete choice: when expected benefits outweigh expected costs, prices are reset optimally. The model gives rise to a non-linear Phillips curve as prices are more flexible during demand-driven expansions and less so during demand-driven recessions. Monetary policy can have substantial real effects despite the model having a state-dependent pricing component. Our quantitative analysis shows that contrary to the standard NK model, the assumed price setting behaviour: (i) is consistent with micro data on price setting frequency; (ii) generates a direct effect of the time-varying price setting frequency on inflation; (iii) creates time-variation in the Phillips curve slope that explains shifts in the Phillips curve associated with different historical episodes; (iv) explains inflation dynamics without relying on implausible high cost-push shocks and nominal rigidities inconsistent with micro data; (v) reconciles the NK model with observed inflation moments.