US Patent 7917503 Specifying relevance ranking preferences utilizing search scopes

A mechanism for expressing a user preference to a set of documents based on user knowledge about the document corpora. The user preference input to the system can be positive, negative, or both. A set of documents that can be identified with a query can define a search scope definition. The search scope is mapped into an input ranking feature for a ranking function. The search scope definition is employed as a soft preference ranking feature, and thus, used to bias ranking via relevance feedback. The mechanism facilitates increasing or decreasing the final ranking score of a document based on whether the document falls into the user scope. The ranking weight can be configured by the user ad-hoc, or when relevance judgments are available, using machine learning techniques to find the optimal weights to optimize ranking.