The Tax-Calculator simulates federal individual income and payroll taxes for each tax filing unit in a sample. For revenue estimation, that sample must be representative of the US population.
This project commonly relies on a micro dataset that closely reproduces the multivariate distribution of income, deduction and credit items in 2009, extrapolated to 2015-2026 levels in accordance with CBO forecasts available in Spring 2016. It is intended to match similar but confidential data used by the Congressional Joint Committee on Taxation. The underlying dataset must be purchased from the Statistics of Income division of the Internal Revenue Service. Additional information on non-filers is taken from the March 2013 Current Population Survey.
The open source TaxData model implements the extrapolation and statistical match.