Regardless of how you are searching, you should first make sure that you're searching cases in the correct jurisdiction. In this context, jurisdiction means which court system the case was heard in.
If you are researching in print, make sure you are using the appropriate digest system. The Texas State Law Library carries West's Texas Digest, West's Federal Practice Digest *, West's Bankruptcy Digest *, and West's Decennial Digest *. Each of these title contains cases from a different jurisdiction and will therefore contain different cases under identical key numbers. For this reason, it's important to make sure you're searching with the right tool.
* These titles are no longer kept up to date by the library
If you are researching online, all legal databases will give you the option to limit your search to specific jurisdictions.
Restricting your search to the correct jurisdiction may make a big difference in the relevance of your results! For example, citing to a Pennsylvania case that appeared in your search results because you didn't choose the correct jurisdiction may not be helpful in your lawsuit over a Texas law.
Please see the short videos below for instructions on how to select the proper jurisdictions prior to running your search.
Before you rely on a case in your legal proceeding, you should check to make sure that it is still "good law." That means that there have not been any cases after it that disagree with it or find that its reasoning was flawed. Ideally, it would also mean that there were cases out there supporting the judgment of your case. The way to do this is using a citator, such as West's KeyCite or Lexis's Shepard's. A citator provides a list of all the cases that have cited to a particular case and will give you an indication about whether it was discussed positively or negatively. Negative discussions mean you should proceed with caution when relying on that case.
Shepard's Citations is the most famous citator. For that reason, you will often see the process of looking for how other cases treat a case referred to as Shepardizing. Shepard's is owned by Lexis and has been incorporated into Lexis Advance. Shepardizing a case is easy! When viewing a case in Lexis Advance, the column to the right will show you Shepard's information. Easy-to-identify symbols will give you information about what other cases have said about this case at a glance. Running the full Shepard's report will give you a list of all of the cases that cite to it, how detailed the discussion of the case was, and whether the treatment was positive or negative.
West has developed its own citator called KeyCite. It functions in much the same way as Shepard's. KeyCite also uses visual indicators to help you identify at a glance whether your case can be relied upon.
Authority Check is not a traditional editorial citator, where editors would review the case history and make a determination about its status. Authority Check uses the Bad Law Bot to search case law and identify negative treatment using algorithms.