Matching inter-temporal marginal propensities to consume

19-12-2024

This paper solves the issue of matching inter-temporal MPC in a one agent setting by combining consumption habits with reference consumption regarding liquid income (a "hand-to-mouth" term).

Abstract

This note proposes a new model to explain the persistence of high marginal propensities to consume (MPCs) observed following one-time transfers, which traditional business cycle models struggle to match. Unlike standard approaches that rely on a mix of Ricardian and hand-to-mouth agents, this model uses a representative agent framework with consumption habits and a "hand-to-mouth factor"- a fraction of liquid income spent in each period. This setup generates a high on-impact MPC, spread over several periods, aligning with empirical data. The model has two key advantages with regards to implementation in the MAKRO CGE model: it replaces ad-hoc consumption frictions with optimizing behavior, ensuring persistence in MPCs, and simplifies the model by removing hand-to-mouth agents, reducing both complexity and calibration effort.