The importance of link evidence in Wikipedia

Wikipedia is one of the most popular information sources on the Web. The free encyclopedia is densely linked. The link structure in Wikipedia differs from the Web at large: internal links in Wikipedia are typically based on words naturally occurring in a page, and link to another semantically related entry. Our main aim is to find out if Wikipedia’s link structure can be exploited to improve ad hoc information retrieval. We first analyse the relation between Wikipedia links and the relevance of pages. We then experiment with use of link evidence in the focused retrieval of Wikipedia content, based on the test collection of INEX 2006. Our main findings are: First, our analysis of the link structure reveals that the Wikipedia link structure is a (possibly weak) indicator of relevance. Second, our experiments on INEX ad hoc retrieval tasks reveal that if the link evidence is made sensitive to the local context we see a significant improvement of retrieval effectiveness. Hence, in contrast with earlier TREC experiments using crawled Web data, we have shown that Wikipedia’s link structure can help improve the effectiveness of ad hoc retrieval.