A preemption check is checking to see whether someone else has already written an article that:
Don't conclude you are preempted unless after reading those articles you find that you have no new, worthwhile insights to offer.
For help in the art of preemption checking, run the Preemption Checking CALI Exercise.
For a thorough preemption check, take the following steps:
Look for references to legal articles using legal periodical/journal indexes.
Search for legal articles using full-text periodical/journal databases.
Search for non-legal articles if your topic has an interdisciplinary slant.
Search for pre-publication postings of a work in progress on Social Science Research Network [SSRN].
Set up alerts to keep current on newly-published articles.
At each stage use a variety of sources and a variety of search techniques. The more sources and search techniques you use, the more confident you can be that you have found all of the articles related to your topic, and that you have not overlooked a preempting article.
Keep a log of the sources you checked and the searches you did, so that you don't accidentally skip a step — or repeat a step unnecessarily.
A thorough preemptive check verifies that no other article quite like yours exists.
You cannot say "there is no article like this" until you have checked everywhere that similar articles might be found, using every resource that exists for finding law review articles and using different types of searches. So, preemption checking requires an usual degree of thoroughness, and a tolerance for a certain amount of tedium
The payoff for the painstaking work of preemption checking is twofold. First, you can be reassured that you will not spend months researching and writing an article that cannot be published.
Second, you will come away with a portfolio of articles that will help you refine and research your topic.
Suppose you find an article very similar to the one you propose to write. Are you preempted? This is a hard question to answer.
Ask yourself — is there anything at all left to say on this topic? Are their new angles to explore? Can I craft a novel thesis?
Ask an editor or professor. Others may have a more objective view of whether your approach is sufficiently original to merit publication.
Check the following book. Chapter 2 ("Inspiration: Choosing a Subject & Developing a Thesis") has great advice on strategies for close reading of other articles to tease out original and meaningful theses for your own article.