Patent Analysis

The purpose of this chapter is to explain how patent analysis is used for program evaluation, what research questions it can help to answer, how it is performed, and what are its limitations. Examples drawn from an evaluation study using patent analysis illustrate the approach. The analysis of patents is primarily applicable to evaluation of applied research programs and innovation because patents are knowledge outputs and indicators of invention. Patents disclose to society how an invention is practiced in exchange for the temporary right to exclude others from using the patented invention without the patent assignee's permission. Each patent reveals a list of references to informational sources, including publications and other patents, that predate it and that are relevant to the patent's claim of originality—that is they form the "prior art" of the new invention. The revelation of prior art enables an evaluator to identify what previous work has influenced a new invention, and allows the tracing of knowledge dissemination through patent citation analysis.