The following is based on an article about evaluating information that I wrote for our Law School Newsletter a few years back:
First the good news: Legal information may have three desirable characteristics - good, fast, and cheap.
Now the bad news: You can only have two out of the three at one time.
As researchers, we would like for the sources we choose to meet all three criteria. Unfortunately, this is a very rare occurrence. Quite often we must choose which two of these three characteristics are most important for our research needs.
Good and Fast
The most obvious example of legal information that is both good and fast is that which can be found in subscription databases such as Westlaw and Lexis. An experienced researcher can quickly find accurate information to address a legal issue. But, it's not cheap!
In fact, a single search in one of the larger databases could reach almost $200. However, considering the rate at which many attorneys bill their time, this cost may be perfectly acceptable. Remember-time is money.
Good and Cheap
There are several examples of information that is both good and cheap. One might be print resources. Attorneys can often find accurate information using the print resources in the firm's library with no per use search fees. However, it often takes more time to research with books than it does to search a database.
(With the high cost of maintaining print subscriptions, many librarians know that this type of search may not be as inexpensive as it seems. However, many attorneys do not pass on this cost to their clients.)
The Internet could also be considered another source of good and cheap information. There very well might be a free site out there by a reputable author that accurately answers your legal question. But how long is it going to take you to find it?
Fast and Cheap
Internet information can also be categorized as fast and cheap. Using any number of search engines, you can often very quickly find free information on your legal issue. Unfortunately, it may or may not be accurate. In fact, the very first site you find may say that the US Constitution was signed in 1984. Be aware that just because someone "publishes" a site, doesn't mean that the information contained within it is reliable.
Which Two to Choose?
Unfortunately, there is no absolute answer to this question. The type of resource you choose to answer your legal question may be different in every situation. How able is your client to pay for legal services? How comfortable are you using databases versus print resources? What is your hourly billing rate? Do you think the answer you seek will be elusive or easily found?
To be an effective legal researcher, you must learn to balance your time, search costs, and the accuracy of the information you find.