To determine whether a case is still good law, you need to check the subsequent history of the case as well as subsequent citations to see how other cases have treated your case by using citators (Shepardizing on Lexis or KeyCiting on Westlaw).
The symbols and signifier phrases in citators (e.g., yellow flag, red stop sign symbol) only offer clues to how subsequent cases have treated your case, but you must actually read the cases of concern to see how or whether these subsequent cases have called your case into question, whether they apply your case, whether they distinguish your case, etc. The editors of Westlaw and Lexis may not come to the same conclusion about how to "code" a case. Red flags or stop signs do not necessarily mean that a case is bad law. For instance, the case might be bad law on a different issue, the case itself might have been overturned, or the case may simply be unpublished (in some jurisdictions, court rules indicate that you cannot cite unpublished opinions).
Make sure to Shepardize or KeyCite all of the cases before submitting your memo or brief!
To view the subsequent history of a case, click on the "History" tab.
Westlaw provides a map that depicts prior and subsequent history as well as a list of the direct history.
Subsequent Citations (Case Treatment): To view the subsequent citations to a case, click on the "Citing References" tab.
Citing References include all cases that cite to this case. Citing References also include other materials such as secondary sources and court documents, but to ensure that a case is still good law, you only need to check the cases. You can filter the citing references in the left sidebar to narrow the results to include only cases decided by courts that are binding on your court.
Negative Treatment: Westlaw also offers a "Negative Treatment" tab containing negative direct history and negative citing references. Clicking on the status flag next to the case name will also bring you to this Negative Treatment report.
The Shepard's Report contains information about both subsequent history and subsequent citations for a case. To generate a Shepard's Report, click on "Shepardize this document."
Appellate History: To view the prior and subsequent history for a case, click on the "Appellate History" tab in the Shepard's Report. You can opt to view the appellate history in a map if you would prefer a visual, graphical depiction by clicking on the pie chart icon in the upper right (it reads "Map View" when you hover your mouse on it).
Subsequent Citations (Case Treatment): To view how other cases have treated your case, click on the "Citing Decisions" tab. You can filter the citing decisions by treatment or depth of discussion in the left sidebar or also narrow down the cases by jurisdiction and publication status. Lexis's discussion bars indicate the extent to which the case is discussed by the subsequent case: analyzed (4 bars), discussed (3 bars), mentioned (2 bars), or cited by (1 bar).
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