Input Data

SimPaths needs a starting population, tax-benefit donor data, and model parameters. These serve different purposes and should be versioned together for each research application.

Input	Purpose	Where to start
Initial population	Individuals, benefit units and households at the simulation's start year	Initial Population (UK)
Tax-benefit donors	Precomputed UKMOD outcomes used to impute taxes and benefits	Tax-Benefit Donors (UK)
Parameters and targets	Regression coefficients, alignment targets, projections and scenario assumptions	Model Parameterisation

Training and research data

The repository includes initial-population training data and donor training data. Use these with the first-simulation guide to check the installation. Training results are not suitable for substantive analysis.

UK research populations are derived from Understanding Society (UKHLS), with additional sources including the Wealth and Assets Survey. Tax-benefit donors are produced with UKMOD using licensed survey inputs. Access conditions apply to the underlying data and derived records; do not upload restricted data or outputs to the public repository.

Use data releases supported by the compilation scripts for your code revision. A newer survey release is not automatically compatible with an older pipeline.

Obtain data for the initial population

Follow Initial Population (UK) for access, compilation and setup. The Repository Guide explains the pipeline stages and estimation inputs.

Obtain data for tax-benefit donors

Follow Tax-Benefit Donors (UK) to prepare compatible policy-year outputs. Running UKMOD requires Windows; SimPaths can read the resulting precomputed files on other supported platforms.