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Using Lexis, Westlaw & Bloomberg Law

What does it mean when people ask if a case or statute is still "good law"?

Photo credits: Carlos Alberto Gómez Iñiguez, David Guenther, and Ximena Ibañez on Unsplash

Imagine this: you file a brief that relies heavily on the Washington State Court of Appeals case Bigfoot v. Sasquatch. The facts and holding of Bigfoot essentially mean that your client wins. However, during oral argument the judge pointedly asks you why you are relying on Bigfoot when it was overruled by the Washington Supreme Court in Skunk Ape v. Yeti. You had no idea that Bigfoot was overruled and, as such, have no good counter-argument and ultimately lose the case. This unhappy scenario illustrates the importance of verifying that any authority you rely upon, whether it be a case, statute, or regulation, is still valid. Check out this real life example of how important it is to validate.

As demonstrated above, the question of whether a case, statute, or regulation is "good law" is of utmost importance when you are making legal arguments. Primary authority are no longer considered "good law" when:

  • For cases, they are reversed or overruled by a subsequent court opinion or legislative action
  • For statutes, they are repealed or amended by the legislature or invalidated by court opinion
  • For regulations, they are repealed or amended by an executive agency or invalidated by court opinion or legislative action

So where do you go to determine this information? Enter the citator.

An introduction to citators

A citator is a research tool that identifies sources that refer to a particular case, statute, or regulation.

Citators have two main functions: validation and research. The validation function helps you determine the current status of a case, statute, or regulation - i.e., whether or not is is still "good law." The research function helps you find other legal materials (cases, statutes, secondary sources, etc.) to help answer your research question. Below are some examples of these functions:


  • Finding direct history
    • For cases, this includes prior and subsequent history
    • For statutes, this includes reversal, amendment, or pending legislation
  • Finding negative treatment (e.g. your case has been overruled or your statute has been amended)
  • Finding positive treatment (e.g. another case agreeing with the analysis in yours)


  • Finding parallel citations
  • Finding citing references (cases that cite your case, statute, or regulation)
  • Finding relevant secondary sources

The two major online citation services are KeyCite (on Westlaw) and Shepard's (on Lexis). A third and more recent addition to the citation service options is Bloomberg Law's BCite. All three of these services use symbols to visually indicate certain things about a case or statute, wuch as whether it has positive or negative subsequent treatment. Note that while Westlaw's KeyCite and Lexis' Shepard's are available for both cases and statutes, Bloomberg's BCite currently only exists for case law.

Details about each platform's citator are discussed in the sections that follow. For additional information about using citators, check out the following CALI lessons (visit the law student restricted databases page if you need the CALI authorization code):


Shepard's is the citation service offered through Lexis. Shepard's relies on a variety of symbols to act as visual cues regarding the status of a cases, statutes, or regulations. Below are explanations of what each symbols means (as set forth by Lexis):

Additional information about Shepard's on Lexis is available in the Shepard's Signal Indicators and Treatments brochure.


KeyCite is the citation service offered through Westlaw. KeyCite relies on a variety of symbols to act as visual cues regarding the status of a case, statute, or regulation. Below are explanations of what each symbols means (as set forth by Westlaw):

Yellow Flag

  • Cases & Administrative Decisions - some negative treatment, but not reversed or overruled
  • Statutes & Regulations - proposed legislation or rule available, court decision has questioned validity, or prior version received negative treatment from a court

Red Flag

  • Cases & Administrative Decisions - no longer good for at least one point of law
  • Statutes & Regulations - amended, repealed, superseded, or held unconstitutional or preempted in whole or in part
  • RESEARCH NOTE: even if a case, statute, or regulation has a red flag it does NOT mean that the entire authority is no longer "good law." It may only be invalid for one or a few points of law, which is why it is extremely important that you actually read the case or legislation that invalidated your law to see which point(s) are no longer good.

Striped Flag

  • Indicates a document has been appealed to the U.S. Courts of Appeals or the U.S. Supreme Court (excluding appeals originating from agencies)

Orange Circle

  • Indicates that a document may no longer be good for at least one point of law based on its reliance on an overruled or otherwise invalid prior decision (Overruling Risk indicator)

For a brief introduction to KeyCite,check out this video:


BCite is Bloomberg Law's citator for case law. BCite's Indicators exist at both the "Composite Analysis" and "Case Analysis" levels. The "Composite Analysis" is a "visual representation of the Direct History and Case Analysis portions of BCite, displaying the overall status of the case." The "Case Analysis" "summarizes the analysis of the main opinion by cases that subsequently cite the opinion." Below are charts outlining the available indicators for each.

For additional instruction on finding court opinions on Bloomberg Law and using BCite, see this page or check out the following tutorial video: