Investigating external corpus and clickthrough statistics for query expansion in the legal domain
Tonya Custis, Khalid Al-Kofahi · 2008
We apply language modeling keyword search augmented with Berger and Lafferty's (1999) translation model for query expansion to formulate three query expansion methods using word co-occurrence statistics from a large external corpus and user clickthrough data. We study the performance of these methods on a vertical domain (case law documents) using standard metrics and an evaluation framework designed specifically to measure the performance of query expansion under varying degrees of query-document term mismatch.