This document tells you how to begin contributing to Tax-Calculator by reporting a bug, improving the documentation or making an enhancement to the Python source code. If you only want to use Tax-Calculator, you should begin by reading the user documentation that describes how to use Tax-Calculator on your own computer (without doing any programming) and how to use the Tax-Calculator web application called TaxBrain. If you want the most flexibility in using Tax-Calculator on your own computer, start by reading our Cookbook of Tested Recipes for Python Programming with Tax-Calculator.

Tax-Calculator simulates the US federal individual income tax system. In conjunction with micro data that represent the US population and a set of behavioral assumptions, Tax-Calculator can be used to conduct revenue scoring and distributional analyses of tax policies. Tax-Calculator is written in Python, an interpreted language that can execute on Windows, Mac, or Linux.

Results will change as the underlying models improve. A fundamental reason for adopting open source methods in this project is so that people from all backgrounds can contribute to the models that our society uses to assess economic policy; when community-contributed improvements are incorporated, the model will produce different results.

If you want to report a bug, create a new issue here providing details on what you think is wrong with Tax-Calculator.

If you want to request an enhancement, create a new issue here providing details on what you think should be added to Tax-Calculator.

If you want to propose code changes, follow the directions in the Contributor Guide on how to clone the Tax-Calculator git repository. Before developing any code changes be sure to read completely the Contributor Guide and then read about our coding style and testing procedures. The Tax-Calculator release history provides a summary of past and current development work.

If you are relying on Tax-Calculator capabilities in your own project, be sure to read the definition of the Tax-Calculator Public API.

Please cite the source of your analysis as "Tax-Calculator release #.#.#, author's calculations." If you wish to link to Tax-Calculator, http://open-source-economics.github.io/Tax-Calculator/ is preferred. Additionally, we strongly recommend that you describe the input data used, and provide a link to the materials required to replicate your analysis or, at least, note that those materials are available upon request.