SIGIR workshop report: predicting query difficulty - methods and applications

@article{Carmel2005SIGIRWR,
  title={SIGIR workshop report: predicting query difficulty - methods and applications},
  author={David Carmel and Elad Yom-Tov and Ian Soboroff},
  journal={SIGIR Forum},
  year={2005},
  volume={39},
  pages={25-28}
}
Estimation of query difficulty is an attempt to quantify the quality of results returned by the search system for a query. Ideally, a system that can predict difficult queries can adapt parameters or change algorithms to suit the query. Such systems could give feedback to the user, for example, by reporting confidence scores for results, and report to the system administrator regarding topics that are of increasing interest to users but are not answered well by the system.