Patent Searching can be a deceptively difficult, and yet vitally important exercise. There are over 70 million patents out there, and while there are very powerful keyword and class codes search engines that you can use, the results are only as good as:
The keywords and class codes that you search by
The keywords and class codes used by the people who filed or examined the patents you are looking for. No matter how good your choices are, you are also reliant on these other people.
Millions or even hundreds of millions of dollars may depend on the outcome of patent searching - due to the risk of unwanted litigation or wasted R&D and commercialisation costs. Clearly as patent searchers we need to do the best possible search in the time that we have available. The same applies to patent examiners - the right search results can have large economic consequences on both the patent applicants and their competitors.