Electronic citation services are currently available on both Lexis and Westlaw.
KeyCite is Westlaw's citation service that covers all cases on Westlaw, the United States Code Annotated, the Code of Federal Regulations, and statutes from all 50 states. KeyCite arranges this information in a manner that eliminates many of the stylistic details that can make print citators confusing. It also attempts to help researchers determine which subsequent cases are likely to be significant - answering the time-honored question, "Do I have to look at all those cases?"
Instead of listing citing cases in a roughly chronological arrangement with the use of margin codes such as "r" for reversed or "d" for distinguished (as in the print version of Shepard's), KeyCite arranges the citing cases into four categories that indicate the depth of discussion given to the original case. Cases that provide extended discussion (defined by West as more than one printed page) are listed first. Three subsequent categories follow which reflect declining degrees of depth of treatment, ending with a final category of cases that mention the original opinion in passing, usually in a string cite. Within each category, cases from the same jurisdiction as the court that decided the original case are listed first, followed by cases from other jurisdictions. The full text of each case in the listing can be accessed by clicking on its name in the list. Non-case materials, such as secondary sources, that cite the original opinion are also listed at the end of the display and are hot-linked.
KeyCite also permits restriction of the display of citing cases to those dealing with only the issue(s) of particular interest to the researcher. This technique is tied to the West headnotes and their corresponding topics and key numbers. This facilitates coordination of online research with print research techniques.
Texts of cases on Westlaw are linked to KeyCite by a system of graphics
that signal the reader of an online opinion that important subsequent
history or treatment of the opinion exists. Above the title of the case
there may appear a blue "H" for "History" or a red
or yellow flag that signals important negative treatment. Clicking on
the signal takes the reader into the KeyCite display.
The Lexis version of Shepard's also eliminates the use of the history and treatment codes that characterize the print Shepard's. Treatment such as "followed" or "criticized" is indicated by simply including the appropriate word beside the listed citations. Citations are listed by jurisdiction, and in reverse chronological order within each jurisdiction. Headnote numbers - referring back to the headnotes of the cited case- are also listed to help the researcher determine which cases may be most relevant to the issues being researched.
Shepard's provides citations to cases in secondary sources such as law reviews and A.L.R. The Lexis version of cases also includes codes or signals within the text of cases available online to indicate negative treatment, similar to the KeyCite signals that appear on Westlaw.