18. The medium of claim 17 , wherein the operations further comprise: applying the original query and the revised queries to the predictive model to obtain confidence measures for the revised queries based on the respective likelihood of success.
18. The medium of claim 17 , wherein the operations further comprise: applying the original query and the revised queries to the predictive model to obtain confidence measures for the revised queries based on the respective likelihood of success. 21. The medium of claim 18 , wherein the operations further comprise ranking the revised queries according to the confidence measures.