Patent ID: 8275656

Claim:
A network device, comprising: a transceiver to send and receive data over the network; and a processor that is operative to perform actions, including: receiving a plurality of observed click-through rate data associated with a plurality of related advertisements; receiving a related new advertisement for placement, the related new advertisement missing observed click-through rate data; estimating statistical parameters about the plurality of related advertisements using the plurality of observed click-through rate data associated with the plurality of related advertisements, wherein the estimation of the statistical parameters is subject to a covariance constraint such that a lower bound for each covariance is a symmetric, positive-definite matrix; using the estimated statistical parameters, predicting a statistical parameter for the missing click-through rate data for the related new advertisement; receiving a search query; and employing the estimated and predicted statistical parameters to select an advertisement from the plurality of related advertisements and the related new advertisement; and providing a response to the search query with the selected advertisement.