Step 4 of 4 · Learn to buildHow-to guide
LearnDo it with open toolsRun a tax policy simulation
Run a tax policy simulation
Show what a rate or threshold change does to households and to revenue, with the rules in the open.
A route to listed tools, not a lesson, and not tax advice: a person decides.
Open it
The steps, at a high level
- Install the country package: policyengine-us or policyengine-uk (pip), or openfisca-france; each holds the rules as code with parameters and formulas.
- Describe a household or load the survey microdata, define the reform as a parameter change, and compute the outcomes before and after.
- Report the aggregate and distributional results with the package version and the parameter you changed, so the run can be repeated.
Check before you rely on it
- PolicyEngine's READMEs say direct microsimulation through the packages is deprecated in favour of the managed policyengine.py bundle; results are estimates.
- These are tax-benefit models for households; none models corporate provision or Pillar Two.
- AGPL-3.0: a service built on them must publish its source.
Where these tools sit on the map
- Tax policy & stakeholder engagementCompany tax department › Tax Policy & Stakeholder Engagement
- Reform costing & microsimulationTax authority › Policy, Legislation & Revenue Analysis