PolicyEngine
ResearchModelAPIPython
Donate
PolicyEngineModel
Overview
Behavioral responses

The engine

How microsimulation works

PolicyEngine's microsimulation model combines three ingredients to estimate the impact of any tax or benefit reform on every household in the country.

Policy rules

Tax codes, benefit formulas, and eligibility rules encoded as executable logic. Over 55 federal, state, and local programs.

Household data

A representative microdata sample of the population, with income, demographics, and program participation for each household.

Behavioral dynamics

Elasticities capturing how people adjust their labor supply and income in response to tax and benefit changes.

A representative sample of households, each with their own characteristics.

HouseholdEarningsChildren
Household A$30,0002
Household B$75,0001
Household C$120,0000
Household D$50,0003
Household E$200,0001

Current versions

PolicyEngine's country models are open-source Python packages, published to PyPI with every release.

policyengine-us...policyengine-uk...
PolicyEngine

PolicyEngine 2026

Compare
PolicyEngine US with…
Pick one or more peers to switch this model page into side-by-side view.