The Impact of Spelling Errors on Patent Search

The search in patent databases is a risky business compared to the search in other domains. A single document that is relevant but overlooked during a patent search can turn into an expensive proposition. While recent research engages in specialized models and algorithms to improve the effectiveness of patent retrieval, we bring another aspect into focus: the detection and exploitation of patent inconsistencies. In particular, we analyze spelling errors in the assignee field of patents granted by the United States Patent & Trademark Office. We introduce technology in order to improve retrieval effectiveness despite the presence of typographical ambiguities. In this regard, we (1) quantify spelling errors in terms of edit distance and phonological dissimilarity and (2) render error detection as a learning problem that combines word dissimilarities with patent meta-features. For the task of finding all patents of a company, our approach improves recall from 96.7% (when using a state-of-the-art patent search engine) to 99.5%, while precision is compromised by only 3.7%.