Average gain ratio: a simple retrieval performance measure for evaluation with multiple relevance levels Tetsuya Sakai Return to Posters BIBTEX @inproceedings       {DBLP:conf/sigir/Sakai03,   author    = {Tetsuya Sakai},    booktitle = {SIGIR},    title     = {Average gain ratio: a simple retrieval performance measure for evaluation with multiple relevance levels.},    pages     = {417-418},    year      = {2003},    url       = {db/conf/sigir/sigir2003.html#Sakai03},    ee        = {http://doi.acm.org/10.1145/860529},    crossref  = {conf/sigir/2003},    bibsource = {DBLP, http://dblp.uni-trier.de}  } ©2004 Association for Computing Machinery