Assessing thesaurus-based annotations for semantic search applications

Statistical methods for automated document indexing are becoming an alternative to the manual assignment of keywords. We argue that the quality of the thesaurus used as a basis for indexing in regard to its ability to adequately cover the contents to be indexed and as a basis for the specific indexingmethod used is of crucial importance in automatic indexing.We present an interactive tool for thesaurus evaluation that is basedona combinationof statisticalmeasures and appropriate visualisation techniques that supports the detection of potential problems in a thesaurus. We describe the methods used and show that the tool supports the detection and correction of errors, leading to a better indexing result.