Serious and competent legal research is not easy to do. There are many stumbling blocks inherent in the process, and I will discuss five: a basic lack of knowledge in the area of law, a misunderstanding of what case law is persuasive and what case law is dispositive, the lack of precedent that is legally and factually on point, a failure to research the other side of the question, and missing the crucial step of updating one's research.
First, each area of law has important principles and terms of art. If you do not have at least a basic understanding of these, intelligent research is virtually impossible. Legal research requires that you read cases, and if you do not understand the vocabulary and principles in a particular area of law, you cannot understand what you are reading, much less apply what you are reading to the case at hand. To avoid this problem, it is best to familiarize yourself with the area of law before you do any research at all.
Second, there are millions of cases out there, but while they may seem to apply to your research project, you must be able to ascertain what weight these cases carry. Do you have a case that is within your own state or of federal jurisdiction? A federal case will not necessarily apply to state law, and conversely, a state case will not almost never apply to federal law. A case from another state may be persuasive, but whatever the precedent is, it is not binding upon the courts in your state. An opinion from a trial court is not binding at all. The only dispositive cases are those that are in your jurisdiction, decisions from the highest appellate court before whom the case was argued. Other decisions may be worthy of mention, but the court is not bound to follow them. It is possible to spend entirely too much time and energy on finding cases your court will simply ignore.
Third, aside from law school research projects, for which there is usually one particular case the professor is hoping you will find, there seldom are cases to be found that have close enough facts in the applicable area of law to be of much use to you. You need to be very creative in your research, and many people have a hard time with this. Often we must argue by analogy, saying the facts in our case are enough like the facts in another court decision to dictate the same outcome, the outcome that is most favorable to our side. Sometimes we must use analogy by arguing that a definition in an entirely different area of law should apply in our case. Each case tells a story, in effect, and you must be able to say that your story is like the story in another case, so your story should have the same happy ending. It can be difficult to look beyond the facts and law of your own case to expand your horizon enough to do this properly.
Novice researchers in particular can neglect the need to research cases that are against the position to be argued. And they are out there. If you are not aware of these, you have no arguments prepared to counter them when you get to court or must write an appellate brief. It is never enough to do research for your side. You must always do research on the other side, too.
Finally, the day that you are about to file your brief, based upon your great legal research, a court somewhere might be handing down a decision that overturns an important legal precedent that is central to your argument. Before that brief is filed, you must be certain that your research is completely up to date. You can be very sure that your opposition will have found it, and you need to be prepared to be able to counter it. It must be a dreadful feeling to get to court to find out that your position is now completely untenable. There are research tools that allow you to update every case, to see whether it has been upheld or overturned. Every legal researcher must be able to use these tools.
Legal research is not easy, and there is much to beware of. People think that since the advent of the Internet, it should be a simple matter to put a few key words in a search engine and get everything you need. It is not so simple. It requires knowledge, persistence, intelligence, and imagination. But good legal research always pays off in the end.