Exploring Web Scale Language Models for Search Query Processing – Jianfeng Gao (Microsoft)

March 23, 2010 all-day

It has been widely observed that search queries are composed in a very different style from that of the body or the title of a document. Many techniques explicitly accounting for this language style discrepancy have shown promising results for information retrieval, yet a large scale analysis on the extent of the language differences has been lacking. In this paper, we present an extensive study on this issue by examining the language model properties of search queries and the three text streams associated with each web document: the body, the title, and the anchor text. Our information theoretical analysis shows that queries seem to be composed in a way most similar to how authors summarize documents in anchor texts or titles, offering a quantitative explanation to the observations in past work.We apply these web scale n-gram language models to three search query processing (SQP) tasks: query spelling correction, query bracketing and long query segmentation. By controlling the size and the order of different language models, we find that the perplexity metric to be a good accuracy indicator for these query processing tasks. We show that using smoothed language models yields significant accuracy gains for query bracketing for instance, compared to using web counts as in the literature. We also demonstrate that applying web-scale language models can have marked accuracy advantage over smaller ones.
I am a Researcher in Natural Language Processing Group at Microsoft Research. From 2005 to 2006, I was a software developer in Natural Interactive Services Division at Microsoft. From 1999 to 2005, I was a researcher in Natural Language Computing Group at Microsoft Research Asia. My research interests include Web search and mining, information retrieval and statistical natural language processing.

Johns Hopkins University

Johns Hopkins University, Whiting School of Engineering

Center for Language and Speech Processing
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Center for Language and Speech Processing