Req-Rec: High Recall Retrieval With Query Pooling And Interactive Classification

We consider a scenario where a searcher requires both high precision and high recall from an interactive retrieval process. Such scenarios are very common in real life, exemplified by medical search, legal search, market research, and literature review. When access to the entire data set is available, an active learning loop could be used to ask for additional relevance feedback labels in order to refine a classifier. When data is accessed via search services, however, only limited subsets of the corpus can be considered - subsets defined by queries. In that setting, relevance feedback [17] has been used in a query enhancement loop that updates a query.We describe and demonstrate the effectiveness of ReQ-ReC (ReQuery-ReClassify), a double-loop retrieval system that combines iterative expansion of a query set with iterative refinements of a classifier. This permits a separation of concerns: the query selector's job is to enhance recall, while the classifier's job is to maximize precision on the items that have been retrieved by any of the queries so far. The overall process alternates between the query enhancement loop (to increase recall) and the classifier refinement loop (to increase precision). The separation allows the query enhancement process to explore larger parts of the query space. Our experiments show that this distribution of work significantly outperforms previous relevance feedback methods that rely on a single ranking function to balance precision and recall.