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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.


This guide identifies different kinds of laws and secondary sources relevant to federal tax matters, and it points out access points to these materials for researchers.

Learn How to Research Federal Tax Law

Tax Law Research

Some authority carries more weight than other authority. The mandatory authority has the most weight; it is the law in the jurisdiction that applies to the facts of a matter before the court, and it must be addressed by the court. Other authority can still be is persuasive authority; it is made up of laws and secondary sources that can by very persuasive or not persuasive at all to a court. A court may, but need not, address persuasive authority. Unique to tax situations is substantial authority, which is made up of both the law and certain very special and very persuasive secondary sources. See IRC § 6662 for more information on secondary authority.

Statutes, like those codified in the Internal Revenue Code, followed by Regulations, like those from the Treasury Department arranged in the Code of Federal Regulations, are two types of law that can be relevant to a tax research matter. Judicial Opinions make up the third type of law that can be relevant.

Some documents from the IRS, an agency under the Treasury Department that deals with tax issues, can be exceptionally persuasive secondary sources. Opinions written by the U.S. Tax Court are given particular weight as well because the judges on the court are experts in dealing with tax matters.

Other secondary sources like treatises and articles on tax issues help one interpret and understand the law properly and refer one to relevant law and IRS documents.