The last step of legal research requires you to make sure your findings are still good law. The big problem with legal research is related to the porous nature of law. Often in law there is no clear answer. There is no rock to be located as in geology or a new insect to be described as in entomology. When do you know that what you have is the answer to your query? What represents the law? Is it a statute, a case, an administrative rule, or all of them? Is there a Supreme Court decision that has declared your findings unconstitutional?

Assuming that you have decided what the responsive answer to your question is, the final question remains, is it still binding? Is it still the law of the land? Has the Supreme Court held it unconstitutional? Has it been amended or reversed?

All these questions will be further addressed when we discuss researching the law in more detail. We will talk about updating each type of legal research – statutory, case law, and administrative - in those particular sections.

This wiki focuses on legal research that is free-of-charge. Lawyers cannot use only free-of-charge resources, as of the date this wiki is written, because there is no comprehensive way of doing correct case law research for free, and both statutory and administrative law research requires case law research to be complete. For that reason, attorneys need to use Lexis, or Westlaw, and BloombergLaw.com, or cheaper alternatives, usually offered through state bar associations, to perform case law searches and implicitly update their legal research.

The three digital aggregates, Lexis, Westlaw and Bloomberglaw have developed their own updating service: Lexis uses Shepard’s, Westlaw uses KeyCite, and BloombergLaw.com, B-CITE. For a fee, those services will reliably update the source whose citation you type in the appropriate search box in a matter of seconds.
In the appropriate chapters, this wiki will explain to what extent updating services can be substituted through free-of-charge full text searches.