To many law students, legal research presents a challenge because it differs in many ways from the research they may have conducted as undergraduates. It is essential to establish a clear understanding of the goals of research in the legal context, and of the various types of legal materials and their interrelationships.
An initial step in developing legal research expertise is to develop an awareness of the types of materials that constitute "the law," and of the relationships between these materials. In the process of researching a legal issue, it may be necessary to consult statutes (legislative enactments), cases (opinions of the judiciary), and/or regulatory materials (administrative agency regulations and decisions). All these types of materials are considered "primary sources." A major challenge for a novice researcher is to gain a perspective on how such sources may apply to a particular subject matter and how they relate to each other. It is often necessary to consult multiple sources and use different techniques for each type of source. Furthermore, for a given problem relevant materials may exist on any or all of the federal, state, or local levels.
A major area in which legal research differs from research a student may previously have conducted is in the need for comprehensiveness in primary authority research. When presented with a legal issue, the researcher must endeavor to locate any potentially relevant authority which would be binding in the applicable jurisdiction. Most important for the beginning researcher to appreciate is that cases or statutory provisions which seem not to favor a client's position cannot simply be ignored and other authorities relied upon instead. Rather, these sources must be discovered, thoroughly analyzed, and distinguished if possible.
Because law is organic, the legal researcher must also learn to appreciate the need to update and verify every source upon which (s)he intends to rely in developing a legal argument. For example, the precedential value of cases is frequently affected by subsequent judicial analysis or by the actions of legislatures. Likewise, it is not unusual for statutes to be repealed or amended by the legislative body; statutes may also be applied and interpreted by case law. The researcher must update carefully in order to accurately assess the significance of any authority.
Another matter which often challenges beginning legal researchers, is the need to analogize. For many of the problems you may be asked to research, no precisely “on point” - meaning factually identical - authority exists. Judges decide disputes before them, and lawyers build arguments, based on a reasoning process which analogizes that a rule of law applied to one set of facts should logically be applied to another set of factual circumstances. Thus it is rarely sufficient to look for authorities that deal with facts too closely resembling those which you have been presented.