A computer trainer I know well tells me that there was much discussion in his company as to whether they should charge for searches that returned no results. After great debate it was concluded that zero hits was a legitimate search result, and, as such, the company should charge for it. I think anyone who carries out research would agree with this: knowing that something has not been considered or talked about is important. The difficulty with this is knowing if zero genuinely is the answer, rather than the result of not using a relevant resource or search term. It’s the classic “Is absence of evidence evidence of absence?” conundrum.
So how do you know when zero is your answer: that the information you are looking for is just not available rather than you just haven't found it yet?
If you are searching for a specific court judgment or tribunal decisions, knowing what is likely to be available is very helpful. While a number of legal matters do not get publicly reported for reasons of confidentiality (for example, a number of arbitration decisions), you would be very surprised not to find a Supreme Court of Canada decision that someone had referred to, however obliquely.
If you are searching case law and finding nothing, the question is whether you are searching correctly. It is possible for a case or an academic article to discuss the very subject you are interested in without ever mentioning your keywords. Publishers have been trying to improve the quality of search results by introducing "smart searching" to the databases, but it remains important to use synonyms in your search.
Another challenge is when you are deliberately trying to find negative information. For example you might be asked to confirm that there are no regulations or orders made under a specific section of an act. If you haven’t found any regulations, does that mean that no regulations exist or that you just haven't located them?
Time and financial constraints do mean you are unlikely to ever perform an absolutely exhaustive search. On the bright side there are a number of things you can do to ensure you feel confident about your search results:
Figure out how likely it is that the thing you are looking for exists. If the person you are doing research for categorically states that item X exists, you are going to be less sure about a zero answer than when doing a search for someone who says “I don't think X exists, but check anyway.”
Make sure you are using all the relevant terms and their variants in the search. Depending on the jurisdiction, they may use a very different term than the one you are used to. (Canadian v. U.S. securities law is an obvious example here, but there are many others.)
Keep a list of sources consulted. The advantage of this is that it makes it easier to see what has been consulted and what hasn’t. If you need to repeat the search for a similar question, you already have a pathfinder. You should also include a list of search terms used with your search results.
Talk to an expert. For example if you’re looking for an obscure piece of government legislation (and confidentiality permits), contact the government body responsible. B.C.’s former Registrar of Regulations was a wonderful resource when you had a knotty question about regulations. (There’s also an additional level of confidence when the Registrar tells you that a regulation does not exist.)
- Use print as well as electronic resources. As generations of librarians will attest, a good index is incredibly valuable. A textbook dealing with the subject you are interested in may answer your question without any need for additional searching, and will probably be an excellent source for search terms that you might not have thought of.