document: Affinity rank : a new scheme for efficient web search Maximizing only the relevance between queries and documents will not satisfy users if they want the top search results to present a wide coverage of topics by a few representative documents . In this paper , we propose two new metrics to evaluate the performance of information retrieval : diversity , which measures the topic coverage of a group of documents , and information richness , which measures the amount of information contained in a document . Then we present a novel ranking scheme , Affinity Rank , which utilizes these two metrics to improve search results . We demonstrate how Affinity Rank works by a toy data set , and verify our method by experiments on real-world data sets .
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