Patent ID: 8126894

Claim:
A computer-implemented method of computing relevancies of documents to queries submitted to a search engine software server hosted on one or more server computers that are configured to receive the queries via a network from client computers, the one or more server computers also being configured to return via the network to the client computers search results configured to be displayed on the client computers, a search result comprising a listing of documents in an order according to relevance to a corresponding query as determined by the search engine, the method comprising: accessing a click chain model (CCM) inference engine, the CCM inference engine having been trained with a click chain log comprising click chains each indicating which documents at which respective order positions of a corresponding particular search result were clicked or not clicked by a user that viewed the particular search result, where the CCM inference engine models the click chains such that, for a given query and a corresponding search result comprising a given document and a document preceding the given document, a probability of a user examining the given document in the given search result conditionally depends directly on a first probability, a second probability, and a third probability, where: the first probability comprises a probability that the preceding document is examined by a user viewing the given search result; the second probability comprises a probability that the preceding document is clicked on by a user viewing the given search result; the second probability conditionally depends directly on the first probability; the second probability conditionally depends directly on the third probability; the third probability comprises a probability of the preceding document being relevant to the user with respect to the given query; and receiving a new query from a client at the search engine, using the CCM inference engine to contribute to computation of relevancies of matching documents to the new query, and returning to the client a search result where the matching documents are ranked according to the relevancies, whereby the matching documents are ranked at least in part according to the CCM inference engine.