Skip to Main Content

Federal Tax Research: Basic Resources

Online and print resources to research federal tax.
Hierarchy of Authority for IRS Guidance and Other

Text description of the hierarchy of authority for IRS guidance in the image. A pyramid showing the Internal Revenue Code (the statutes) just above and more authoritative that the IRS "guidance" category of documents. Just under the statute are the first of two levels of the pyramid considered by the IRS as guidance The first of these levels is the Treasury (tax) Regulations, which are the laws that interpret the statutes. Just less authoritative that the regulation at the center level of the pyramid and the only other level considered by the IRS as guidance are the documents contained in the Internal Revenue Bulletin as follows: Revenue Rulings, Revenue Procedures, Notices, and Announcements. These documents are are not the law, but they must be followed by the IRS. Just less authoritative than these IRS Guidance are two kinds of documents called Written Determinations as follows: Private Letter Rulings and the Technical Advice Memoranda. These are only binding on the specific taxpayer to whom they are addressed. At the lowest and least authoritative level of the pyramid are 5 categories of resources called Other IRS Publications and Information as follows: 1 Forms and Publications, 2 News Releases and Fact Sheets, 3 FAQs, 4 Online Help and Resources, and 5 Videos. These are sources of general information but should not be cited as authority for an interpretation of the law.


Statutes are created by the legislative branch of government and organized be subject in the Unites States Code. Statutes are also accessible in some research databases. Here are links to a few access points.

Internal Revenue Code

The Internal Revenue Code (United States Code, Title 26) contains the statutes dealing with income, estate, gift, excise, and employment taxes. The first IRC was passed in 1939, with subsequent revisions in 1954 and 1986. Tax law can also be found in the Bankruptcy (Title 11) and Criminal Law (Title 18) sections of the USC. 

Access Points