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Law Library

Search Strategies: Westlaw Precision, Lexis+, Bloomberg Law: Westlaw

A guide to searching three major legal research platforms

Distinguishing Features

Digests: West Key Number System

The West digest system, a powerful case-finding tool across jurisdictions, is accessible via Westlaw. The most common way to access key numbers is from the headnotes of a case; but you can also browse and search the key number system from the Tools tab: Tools > West Key Number System.

Tools & Resources

When you're looking at a particular document or browsing a particular database in Westlaw, you will often see a right-hand column titled Selected Topics, listing finding aids and secondary sources to further your research. This might include the index to the document you're browsing, or other related secondary sources.


In addition to running keyword searches to begin your research, Westlaw offers several browsing options, broken down by content type, federal materials, state materials, topics, and other West tools. This browsing capability is an excellent way to get a feel for what Westlaw has to offer.


Search for a document using KeyCite by placing 'kc' or 'keycite' before your search. Alternatively, when viewing a document click the KeyCite flag or tabs labeled 'Negative Treatment', 'History', or 'Citing References'.

Results may be filtered by source, depth of treatment, headnotes, and status.

Case Flags
Flag Meaning - Cases Meaning - Legislation
Yellow Some negative treatment, but not reversed or overruled. Amended, repealed, superseded, held unconstitutional, or preempted in whole or part.
Red No longer good law for at least one point. Renumbered, transferred, limited, validity questioned, or an earlier version received negative treatment.
Blue striped Appealed to US Courts of Appeal or US Supreme Court  

Basic Search

Westlaw search box

Westlaw Precision is designed so that you can run any search simply from the main search bar and filter your results afterwards (by content type, jurisdiction, date, etc.).  The only pre-search filter available is jurisdiction, from the drop-down menu to the right of the search bar.  Within that main search bar, you can run a keyword search, search by citation, search for a specific resource, or even search using a specific Westlaw database.

Advanced Search

Westlaw Precision also gives you the option to conduct an advanced search by clicking the 'advanced' link to the right of the search button. This allows you greater control over how your search will be conducted. For instance, you can require that your search results contain all of your search terms, any of your search terms, or an exact phrase. You can also ensure that certain terms are excluded from your search results. In addition, the Advanced Search allows you to restrict results by date and search by citation, name, or title. 

Two things to note here:

  • By utilizing the Westlaw Connectors and Expanders you can run advanced searches from the main search bar.
    •  The Connectors and Expanders can be viewed by clicking on 'advanced' in Westlaw or by looking at the table on the last page of this guide, Constructing Searches.
  • The Advanced Search features change if you search within a specific Westlaw database, for instance Secondary Sources.


Sometimes it is more efficient simply to browse for a specific title that you are looking for. When looking for the wording of a section of the US Code, for example, it is likely to save time to use the browse option to find the correct section, rather than sorting through all the results of related materials that a search produces. For example, it is quite easy to browse to: USCA > Title 17: Copyrights > 108. Limitation on exclusive rights: Reproduction by libraries and archives, even when you do not know the specific section number or title you are looking for.

It is also worth remembering that some materials rarely appear in search results at all, since they are obscure or out of date, and these are usually easier to find by browsing.