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Shepard’s Outshines KeyCite as Reliable Citation Service for Legal Research

May 16, 2024 (5 min read)

By: Karen Hay

The foundation of accurate legal research is ensuring that your citations are good law. Citing outdated, overruled or irrelevant cases not only weakens your credibility and undermines your persuasiveness. It can also be a costly mistake for both you and your client in some instances.

Any first-year law student can tell you that the best way to have confidence that your research contains cases with precedential value is to use a legal citations service that can verify accuracy and currency of those cites. But if you think any citation service is as good as another, you might want to think again.

The History

In the 1870s, a publishing salesman named Frank Shepard invented the first product that attempted to provide legal professionals with citations of all the authorities citing a particular case or statute. That product would eventually be known as Shepard’s Citations and was the only legal citation service that provided coverage of “good law” in the U.S. for the next century.

This is why generations of law students have been taught they need to “Shepardize” and be sure they are testing the accuracy of their legal research against the most comprehensive editorial analysis of case law, statutes, regulations and administrative decisions.

During the 1990s, Westlaw introduced KeyCite, a competitive legal citation service to Shepard’s. In an age where online research tools can sometimes feel like commodities, it might be tempting to assume that these services are using the same technology to comb the same databases and return the same results. Empirical research suggests otherwise.

Proof is in the Results

Each year we conduct a study to test how Shepard’s compares with KeyCite in head-to-head evaluations of identical cited cases. This is an important annual exercise to identify areas in which we need to improve the Shepard’s service and to help our customers understand the important differences between the two services.

We recently completed our April 2024 research and discovered 114 cases in which KeyCite produced inaccurate treatment of a case’s precedential value versus the accurate treatment produced by Shepard’s. These cases involved court decisions handed down by state courts from Alaska to Virginia, as well as federal courts in various regions of the country.

Our empirical research and analysis identified one particularly noteworthy finding: KeyCite seemed most vulnerable to errors in cases where there were nuances that required legal judgment in the evaluation of a precedent. This suggests that Shepard’s is a more reliable citation service because the methodology involves deeper human involvement and a quality model that can be trusted for greater accuracy.

Why Shepard’s Leads the Way

The LexisNexis team of attorney-editors who maintain the Shepard’s Citation Service follow rigorous quality controls for case law and a strict 29-step editorial process. There are a few key reasons why Shepard’s offers legal researchers a compelling edge:

  • Clear signals
    Shepard’s utilizes red octagons and yellow triangles to convey negative or potentially negative treatment of a citation. This saves users time by providing fast visual clues about how to proceed.



 Red Stop Sign

Warning - Negative treatment indicated - indicates that citing references or history in the Shepard's Citations Service contain strong negative history or treatment of your case (e.g., overruled by or reversed).

 Red Exclamation Mark in a White Circle

Warning - indicates that citing references for a statute in the Shepard's Citations Service contain strong negative treatment of the section (e.g., the section may have been found to be unconstitutional or void).

 White Q in an Orange Square

Questioned: Validity questioned by citing reference - indicates that the citing references or history in the Shepard's Citations Service contain treatment that questions the continuing validity or precedential value of your case because of intervening circumstances, including judicial or legislative overruling as mentioned in the citing reference.

 Yellow Triangle

Caution: Possible negative treatment indicated - indicates that citing references or history in the Shepard's Citations Service contain history or treatment that may have a significant negative impact on your case (e.g., limited or criticized by).

 White Plus Sign in a Green Diamond

Positive treatment indicated - indicates that citing references or history in the Shepard's Citations Service contain history or treatment that has a positive impact on your case (e.g., affirmed or followed by).

 White A in a Blue Circle

Citing references with analysis available - indicates that citing references or history in the Shepard's Citations Service contain treatment of your case that is neither positive nor negative (e.g., explained).

 White I in a Blue Circle

Citation information available - indicates that citing references or history are available in the Shepard's Citations Service for your case, but the references do not have history or treatment analysis (e.g., the references are law review citations).
  • Highlight direct impacts
    Shepard’s prioritizes cases that directly impact your cited case’s value. It highlights decisions that are overruled, reversed or limited the scope of your precedent, allowing you to quickly assess its ongoing relevance.

  • Intuitive search
    Shepard’s is navigated with a user-friendly interface and intuitive search functions. This minimizes the learning curve, allowing you to research efficiently and then get to work faster on crafting your legal arguments that are based on accurate case law.
  • Map the case history
    Shepard’s surfaces a case’s journey through the courts, revealing all appellate decisions and their impact. This comprehensive approach paints a clearer picture of the case’s legal weight and/or potential limitations.

If you’re not using Shepard’s Citations Service, you just might be missing something, such as important support for your argument or the fact that a decision has been newly overturned.

Experience Shepard’s for Yourself

Shepard’s is seamlessly integrated with the Lexis+ platform, which includes access to legal research, data-driven insights, practical guidance and legal news. This allows for effortless workflow — no switching is required between legal research and citation service functions — and maximizes efficiency.

If you are an existing Lexis+ customer, you can access Shepard’s directly within the platform. If you are interested in obtaining access to Shepard’s, click here for an instant free 7-day trial of Lexis+ and look for Shepard’s Citation Service on the platform.