This is the documentation for PolicyEngine Core, the open-source Python package powering PolicyEngine’s tax-benefit microsimulation models. It is a fork of OpenFisca-Core, developed and maintained by OpenFisca.
PolicyEngine Core does not simulate any specific tax-benefit policy: instead, it is a general framework for building tax-benefit microsimulation models. It is currently used by PolicyEngine UK and PolicyEngine US, which each define the custom logic, parameters and data required to simulate the tax-benefit systems of the UK and the US respectively.
The country models each provide:
A set of entity types (e.g.
A set of parameters (e.g.
parameters.tax.flat_tax.rate). Parameters are global data points that have different values for different time periods.
A set of variables (e.g.
income_tax). Variables are properties of entities that can be dependent on entities (including other variable values), parameters and the time period.
PolicyEngine Core then enables users to:
Calculate the value of a variable in a specific time period.
Trace the computation tree of a calculation.
PolicyEngine Core also includes many helper functions designed to simplify the process of modelling a country’s policy.