To help customers who are still in the exploration phase, Web search engines and e-commerce websites often provide relevant Q&As in widgets, such as ‘People Also Ask’ and ‘Customers Also Ask Alexa’, with additional information. In this work, we propose to enrich this customer experience by rendering related products under each Q&A based on an automated online query recommendation. We define what are the tenets for high-quality query recommendations and explain why this challenge is different from the existing query re-writing, query expansion and keyphrase generation methods. We describe a data collection method which uses customer co-click information on a proprietary website in order to successfully guide our model into generating query recommendations that satisfy all tenets. Offline and online evaluation results demonstrate that our proposed approach generates superior query recommendations and brings much more customer engagement over strong baselines.

The focused retrieval task is to rank documents' passages by their presumed relevance to a query. Inspired by work on cluster-based document retrieval, we present a novel cluster-based focused retrieval method. The method is based on ranking clusters of similar passages using a learning-to-rank approach and transforming the cluster ranking to passage ranking. Empirical evaluation demonstrates the clear merits of the method.

Our main goal is studying the merits of using inter-passage similarities for the task of focused retrieval; i.e., ranking passages in documents by their relevance to an information need expressed by a query. As an initial research direction we study the cluster hypothesis for passage (focused) retrieval. We propose a novel suite of cluster hypothesis tests that employ inter-passage similarities and demonstrate that the cluster hypothesis holds for passages. In addition, we present several future directions we intend to pursue.

The cluster hypothesis is a fundamental concept in ad hoc retrieval. Heretofore, cluster hypothesis tests were applied to documents using binary relevance judgments. We present novel tests that utilize graded and focused relevance judgments; the latter are markups of relevant text in relevant documents. Empirical exploration reveals that the cluster hypothesis holds not only for documents, but also for passages, as measured by the proposed tests. Furthermore, the hypothesis holds to a higher extent for highly relevant documents and for those that contain a high fraction of relevant text.