Quantifying Query Ambiguity with Topic Distributions

Query ambiguity is a useful metric for search engines to understand users' intents. Existing methods quantify query ambiguity by calculating an entropy of clicks. These methods assign each click to a one-hot vector corresponding to some mutually exclusive groups. However, they cannot incorporate non-obvious structures such as similarity among documents. In this paper, we propose a new approach for quantifying query ambiguity using topic distributions. We show that it is a natural extension of an existing entropy-based method. Further, we use our approach to achieve topic-based extensions of major existing entropy-based methods. Through an evaluation using e-commerce search logs combined with human judgments, our approach successfully extended existing entropy-based methods and improved the quality of query ambiguity measurements.