Many documents you file with the court will cite prior precedent as part of your argument. When citing prior precedent in court filings, it’s vital to ensure the case is still valid. If you cite an overturned precedent, the court will likely reject your argument. To succeed, you need up-to-date information.
In the past, verifying precedents required a tedious search through published volumes called Shepard’s Citations (which is why it’s called “shepardizing”), but today, databases like Lexis+ and Westlaw do this instantly.
In the new Lexis+ system, shepardizing a case is simple. When you look at a case listing in Lexis+, on the right-hand side of the screen it will have a section labeled Shepard’s™ that summarizes the results of shepardizing that case. In that section is a button that says “Shepardize document” that takes you to a more complete list of how later cases have treated this precedent.
Lexis uses a simple color-coded system to help you see at a glance the results of the shepardization. Blue and purple octagon icons indicate a neutral citation of the case. Green diamonds show that the case was treated positively in a later case. Yellow triangles show that a later judicial decision limited or criticized the precedent, so you should exercise caution. An orange box with a Q in it means that a later decision questioned whether the precedent is still valid. Worst of all, a red exclamation point or stop sign indicates strong negative treatment by later courts, which could mean some or all of the precedent has been overruled, reversed or ruled unconstitutional. If you need to remember what these symbols mean, there’s a “Legend” link on the Shepard’s results page that will summarize them for you. When looking at the Shepard’s results, you can click through to any of the cases Lexis found to see the full judicial decision. This can help you understand the full legal reasoning.
Shepardizing your case is an important tool to use when preparing your legal filings. You need to know the precedents you cite are still valid, and Lexis+ can make that easy to find out. All library patrons can access Lexis+ in-person at the Allegheny County Law Library.
If you have further questions about shepardizing cases, or about any other aspect of legal research, contact the Allegheny County Law Library at ACLL@carnegielibrary.org or at 412-350-5353. If you wish to become a member of the ACLL, you can sign up on our membership page. You can also register for a Carnegie Library of Pittsburgh library card on our website.