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Levin College of Law

Conducting Legal Research

Resources and tips for conducting legal research .

To Validate a Primary Source

You must update (or validate) primary sources:

  • For a case, look at the negative citing references that are binding in your jurisdiction to make sure that the point of law you want to use is still good law.
  • For a statute, look at any legislation that may have impacted the statute section you wish to use AND look at any cases that are binding in your jurisdiction that have interpreted that statute section as unconstitutional or preempted.

Whether you're using Lexis or Westlaw, rely on the signals provided to lead you to those cases and legislation that may have impacted the primary law that you're relying on for your research.  See the boxes below for more detail about validating a law.

To Expand a Primary Source

You can also use KeyCite to expand your research:

  • For a case, look at the citing references underneath a specific headnote, within a specific jurisdiction, for a strong depth of treatment source.
  • For a statute, look at the Notes of Decisions that are most relevant to your research, and look at the Context & Analysis to see if there are any additional secondary sources that you may have missed.

Also see the page on Using Headnotes for more information about expanding your research.

KeyCite Signals

KeyCite Signals (Analysis):
Each document is assigned a signal to make it easy to identify a document’s status.  These signals appear in the top left of the document, next to the case citation or the statute citation.

The signals are defined as follows:

    The document is no longer good for at least one point of law.
  • A court has overruled the case, vacated a judgment; the statute has been held unconstitutional, void, or repealed.
  • This does not automatically disqualify a case or statute from use.  If the citing reference is from a binding jurisdiction, read it to see if your point of law is affected and if so, how.

Some negative treatment but not overruled or reversed; proposed legislation
  • If the citing reference is from a binding jurisdiction, read it to see if your point of law is affected and if so, how.
Document has been appealed to the U.S. Court of Appeals or the U.S. Supreme Court
  • Excludes appeals from agencies.

How to Update a Case Using KeyCite

When you see a red flag, follow this procedure:

  • In the case you wish to cite, note the page numbers AND Headnote for the part of the case you wish to cite.
  • Click the Negative Treatment tab.
  • Look at the reasons why Westlaw says that the case has a red flag.
    • If the reason is because of a statute, click into the statute to see how it impacts the case.
      • If the reason is because of a case, look across to see the jurisdiction of the case. You need only look at cases that are binding in your jurisdiction.
  • Open the case that is binding, then click the green right arrow next to Search term at the top of the page:


This will take you the part of the case that cites to the case you wish to cite.  Read through what the case says about your case, noting whether the case cites to the page number and/or headnote you wish to cite in your case.

Determine what the case says about your case:  does the case overturn, negatively impact, distinguish, etc. your case.  If the case overturns the part of your case that you wish to cite, then you cannot cite to your case for that point of law.

KeyCite for Cases

Across the top of a case, you will see the following tabs:

  • Filings:
    • Briefs, records, motions, etc. available for the case.
  • Negative Treatment:
    • Only those cases that have negatively referenced your case
      • Examples: Superseded by Statute; Not Followed on State Law Grounds; Abrogation Recognized; Disagreement Recognized; Declined to Extend; Distinguished; Limitation of Holding Recognized
      • Note: the signals next to the cases in this list indicate the citing case status, not the status of your case, the cited case.
  • History:
    • Direct history (e.g., trial or district court opinions) and any subsequent cases (e.g. appeals, grants or denials of certiorari).
    • May be able to filter by:
      • All History;
      • Principal History (the important direct history of the cited case; excludes non-dispositive history such as grants of certiorari or review, cases that were consolidated on appeal, etc.);
      • Previous History (all direct previous history of the cited case); and/or
      • Subsequent History (cases decided on remand, after the cited case).
  • Citing References:
    • All references (cases, secondary sources, court documents, etc.) that cite to your case.
    • Can further filter Citing References by:
      • Cases
      • Trial Court Orders
      • Administrative Decisions & Guidance
      • Secondary Sources
      • Appellate Court Documents
      • Trial Court Documents
    • Note: not all types of documents will appear within Citing References – it depends on whether the casehas been cited by that type of reference.
    • Once you’ve filtered to a specific type of document, you will have further filtering options that will vary by type of document.  Possible options are:
      • Jurisdiction (state and/or federal)
      • Depth of treatment (how much the citing case analyzes the cited case)
        • : extended discussion (more than a page)
        • ​​​​​​​​​​​​​​: substantial discussion (more than a paragraph)
        • ​​​​​​​​​​​​​​: some discussion (less than a paragraph)
        • : brief reference or citation only
    • Headnote topics
    • Date
    • Publication name
  • Table of Authorities:
    • All cases cited by the case that you are viewing.
    • Information includes:
      • Treatment of the cited case
      • Depth of treatment of the cited case
      • Whether your case quoted the cited case
      • The page number cited by your case.

KeyCite for Statutes

Across the top of a statute, you will see the following tabs:

  • Notes of Decisions:
    • Selected cases (grouped by topic) that directly interpret a section of the statute
  • History:
    • Legislative history of the statute, including enacting legislation and amendments.
  • Citing References:
    • All references (cases, secondary sources, court documents, etc.) that cite to the statute.
    • Option to filter Citing References by whatever documents are available, such as:
      • Cases
      • Trial Court Orders
      • Regulations, Administrative Decisions & Guidance
      • Administrative Filings
      • Secondary Sources
      • Appellate Court Documents
      • Trial Court Documents
    • Note: not all types of documents will appear within Citing References – it depends on whether the statute has been cited by that type of reference.
    • Once you’ve filtered to a specific type of document, you will have further filtering options that will vary by type of document.  Possible options are:
      • Jurisdiction (state, federal, administrative board)
      • Referenced in Notes of Decisions
      • Notes of Decisions topics
      • Date
      • Reported Status
  • Context & Analysis:
    • Cross-references with other statutes or regulations; law review commentaries; ALRs & treatises; and other secondary sources.
    • Similar to Citing References, you have the option to further filter by type of document:
      • Cross References, CFR, Law Review Commentaries, Library References, ALR Library, Encyclopedias, Forms, Treatises & Practice Aids.
      • Unlike with the other filters, once you have limited to a specific type of document, you do not have additional filter choices.  Instead, you are provided with links to the specific documents.
      • Note: not all types of documents will appear for each statute – it depends on whether the statute has been cited by that type of reference.