PolicyEngine UK is PolicyEngine's microsimulation model of the UK tax-benefit system. It uses the PolicyEngine Core microsimulation framework, which is based on OpenFisca.

The elements are described in different folders. All the modelling happens within the policyengine_uk folder.

• The rates and other system parameters are in the parameters folder.
• The formulas and inputs are in the variables folder.
• This country package comes also with reforms in the reforms folder.

The files that are outside from the policyengine_uk folder are used to set up the development environment. Installation instructions are located along with other documentation in the docs folder.

The model supports multiple different input datasets provided by the user, one of which is the Family Resources Survey,¹ containing microdata on household incomes across the UK. PolicyEngine UK enhances this dataset by fusing it to other surveys and reweighting it to minimize a comprehensive loss metric that measures the difference from an array of administrative totals.

1. Run pip install policyengine-uk

2. Run policyengine-uk and go through the prompt to setup microdata.

The primary maintainer for PolicyEngine UK is Nikhil Woodruff, co-founder and CTO of PolicyEngine (nikhil@policyengine.org).

You may cite the source of your analysis as "PolicyEngine UK release #.#.#, author's calculations."