How financing changes the fiscal multiplier

A government spends one more dollar during a slump. How much does GDP rise? This page lets you explore the answer from my M.Sc. thesis (HEC Montréal, 2023), which compares paying with a lump-sum tax, a labor tax, or debt, in normal times and when interest rates are stuck at zero (a liquidity trap).

1. Simple model: live calculation

This version has a formula for the multiplier, so your browser computes it as you move the sliders. Its assumption: the tax ends the moment the trap ends. The sliders open at the thesis calibration; other settings go beyond the thesis.

Financing
Normal times
Liquidity trap

2. Full dynamic model: thesis results

This version drops the shortcut: the trap ends on its own and the tax can linger after it. That reverses the ranking under a balanced budget. These results come from model runs (Dynare), not live calculation.

Normal times, total effect
Liquidity trap, total effect

Show as a table
MeasureNormal timesLiquidity trap

All values here are thesis scenarios, recomputed with free tools. Total effect means the present-value multiplier over 500 quarters.