The database/source you select for a search is dependent on a number of variables. A rule of thumb that is often heard is to initially select the smallest database containing the type of documents you’re looking for, but this is dependent upon the circumstances. However, researchers now often conduct a broad search and then post-filter results using facets such as jurisdiction, type of material, and date. The following tips may provide guidance:
If you are doing secondary source research at the beginning of a project, it might make sense to run a search in one of the combined secondary source databases that combine materials from journals, treatises, and A.L.R. rather than searching separate sources/databases for this information. Depending on your fee arrangement with the vendor, however, note that higher rates might be charged for searching in the larger, combined sources (see below).
On the other hand, if you are researching a problem that is controlled by the law of a particular jurisdiction, it would be more reasonable to search for case or statutory law in a database that contains only materials from that jurisdiction, at least until you determine whether your research will necessitate an examination of persuasive authorities.
Both systems provide databases of materials for specialized areas of law. Often these databases include portions of statutory or regulatory codes, or of reporters, that are relevant to a particular specialty area. These specialized databases can improve search efficiency, but should be used with caution to ensure that relevant materials are not being overlooked because they do not appear in the selected database.
When doing statutory research, you can sometimes opt to use either an annotated (including references to cases and other materials as well as the statutory language) or unannotated (including the statutory language only) version of the code. Often the annotated code is a better choice because the terms actually used in the statute may not be those generally used when discussing a topic. For example, a particular term may not actually appear in the statute but the term may appear in the case annotations, so your search will retrieve the statute you seek. In other situations, the annotations may be so voluminous or the topic so broad that searching the annotated version creates a large retrieval of irrelevant items.
Probably the most difficult selection decision is among the case law databases. Both Lexis and Westlaw provide numerous databases/sources containing cases from various combinations of courts.
Make certain you are familiar with your institution or firm's billing arrangement with Lexis or Westlaw. Unless you have a flat fee arrangement, you may be billed at a higher rate for use of some large combined databases. ( Even if a flat fee contract is in place, however, searching in a larger-than-necessary database/source may slow you down considerably due to the need to sort through superfluous documents. Also, frequent use of the larger databases/sources may be the basis for fee increases the next time your institution negotiates its contract.