Counting ancestors to estimate authority

The AncestorRank algorithm calculates an authority score by using just one characteristic of the web graph—the number of ancestors per node. For scalability, we estimate the number of ancestors by using a probabilistic counting algorithm. We also consider the case in which ancestors which are closer to the node have more influence than those farther from the node. Thus we further apply a decay factor δ on the contributions from successively earlier ancestors. The resulting authority score is used in combination with a contentbased ranking algorithm. Our experiments show that as long as δ is in the range of [0.1, 0.9], AncestorRank can greatly improve BM25 performance, and in our experiments is often better than PageRank. Categories and Subject Descriptors H.3.3 [Information Storage and Retrieval]: Information Search and Retrieval General Terms Algorithms Keywords Probabilistic counting, link analysis, PageRank

• Type: Conference
• Year: 2009
• Where: SIGIR
• Authors: Jian Wang, Brian D. Davison
• Keywords: Authority Score, Information Retrieval, Probabilistic Counting, Probabilistic Counting Algorithm, SIGIR 2009