This is an incomplete collection of the forms and instructions that were used in the creation of the Taxsim calculator and have been copied to our website for easier access. Pre 2009 forms are stored as original hardcopies at the NBER offices. Not all directories have content and this collection is somewhat haphazard.

FTA Links to DOR form pages.
The State of Wisconsin has a biennial "Individual Income Tax Provisions in the States" that summarize state individual income tax laws for all states. We only learned about these in 2024, so they have not been used in the coding of Taxsim yet, but will be of interest to some users of Taxsim, and to us in the future.
2021
2019
2017
2015
2013
2011
2009
2007
2005
2003
2001

Daniel Feenberg