What is a preemption check?
Preemption check is the process of seeing whether your thesis has already been substantially covered by another publication. Your paper or note should be a piece of original scholarship so you want to make sure that no one else has already written the article that you want to write.
Don't be too quick to reject a topic as preempted. Preemption checking means looking for substantial treatment of your thesis. There may be many articles and books on your general topic, but that doesn't mean you can't write about it. You can still write on a topic that is well-covered if you are presenting a new take on the issue.
There are several recommended databases to search for articles, and you should search more than the Westlaw and Lexis Nexis databases. While they are good resources, they do not cover every law review and journal. Additionally, their databases do not include older issues of journals. To be thorough, your preemption check should include searching multiple databases, including the Index to Legal Periodicals.
Index to Legal Periodicals (ILP) an index of articles dating back to 1908
HeinOnline: Search in the Law Journal Library
LexisNexis: Search in the Law Reviews & Journals database under Secondary Legal.
Westlaw: Search in Journals and Law Reviews under Secondary Sources
If your topic is likely to be covered in non-legal publications, you should also search in EBSCOhost's Academic Search Complete, a multi-disciplinary database with indexing and abstracts for more than 11,900 journals.
For tips on searching in these databases, check out the Finding Articles section of this guide.
The editorial process for journals and law reviews can take up to a year, so there may be very recent articles on your topic that have been accepted by a journal but have not been published yet. A search in Index to Legal Periodicals, Lexis or Westlaw will not find articles that have not been published yet, but you should search in the following databases to locate working papers or articles that have been accepted for publication.
Many scholarly books consist of essays or articles by different authors that are compiled by an editor. As part of your preemption check you will want to see if there has been a book or a chapter from a book written on your topic. Begin your search in WorldCat.org, a database of library collections from around the world. Entries for many books will include the table of contents, so a keyword search will look for titles of books as well as chapters in books.
For tips on locating books, see the Finding Books section of this guide.
Preemption checking is not a one-time event. You should continually check throughout the entire research and writing process to see if something new has been written. You can set up alerts in LexisNexis, Westlaw and Index to Legal Periodicals to notify you when something new is published.