An evaluation of the leading patent equivalents services

Patent equivalent services are useful tools for identifying patent families. A patent family consists of a group of patents in various countries which cover the same invention. The patent equivalents services provided by the three leading suppliers--Chemical Abstracts Service, Derwent Publications Ltd., and INPADOC--have been tested and evaluated for coverage, recall, and accuracy. Results are reported for a test sample consisting of 75 pharmaceutical patent families.