Learning to estimate query difficulty: including applications to missing content detection and distributed information retrieval.

Elad Yom-Tov Shai Fine David Carmel Adam Darlow Learning to estimate query difficulty: including applications to missing content detection and distributed information retrieval. 512-519 2005 conf/sigir/2005 SIGIR http://doi.acm.org/10.1145/1076034.1076121 db/conf/sigir/sigir2005.html#Yom-TovFCD05