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Running a Preemption Check: Home

Preemption checking is the process for determining whether there is any pertinent legal or specialized literature on your topic that has been already been previously published by someone else.

Step One: Books and Chapters

Look for books on your subject in LEAGLE, the Pence Law Library catalog, and on WorldCat, an online database containing most books published in the U.S. and Europe.  Use both to find a book or book chapter that may have been published about your topic.  Search these databases using both keyword searches and subject searches to locate books that might address your topic.  Both are available on the library website ( under Research Tools.

Step 2: Law Periodicals

Look for journal articles on your subject.  DO NOT RELY ONLY ON journals and law reviews (JLR or TP-ALL) on Westlaw or "U.S. Law Reviews and Journals, Combined" or "U.S. Law & Canadian Law Reviews, Combined" on Lexis.  These databases cover only a fraction of the law reviews, newsletters, legal newsletters, and bar journals published in the U.S.  Use these indexes (available on the Research Tools page) to search law journals instead:

Step 3: Current Awareness and Topical Sources

Major legal and non-legal newspapers and websites, including American Lawyer, National Law Journal, New York Times, Washington Post, Slate, Politico, Law360, and BloombergLaw are helpful at this stage of the pre-emption check.  Additional important resources will include:

Beginning your Research

Get organized!  Create a research log, whether in paper, on a spreadsheet, or in a word-processing document.  You will need to keep track of the sources you consult and use for your paper in order to provide complete citations and full bibliographic information of every source you cite or use generally.  Be thorough!

Source Gathering.  If you need a source that is not available at the Pence Law Library, you can obtain it through interlibrary loan (ILL).  Be sure to leave enough time to obtain your source through ILL--it may take as long as two weeks to get your material.

Updating your Research

UPDATE YOUR RESEARCH!  always be sure to use the most current information available.  Use Shepard's and Keycite to insure that the cases you use are still good law, and consult the most recent version of applicable statutes and regulations to determine if they are still in force and have not been amended.

Concluding your Research

Ask yourself the following:

  • Did you answer the question you originally started with?
  • Have you checked and updated all the sources you used and cited?
  • Are you seeing the same sources every time you attempt to do further research?

If you answer yes to these questions, you are probably finished researching--especially if your deadline is approaching.


More questions?  Still looking for a source?  Consult an expert reference librarian!  Come to the Reference Desk in the library or e-mail use at  If it takes you longer than ten minutes to find something, you are better off asking the experts--your librarians!