Ontology Graph Based Query Expansion for Biomedical Information Retrieval

Query expansion based biomedical information retrieval has been studied for over two decades, most of the studies focus only on taking advantage of one vocabulary: MeSH. We propose a completely different approach utilizing an arbitrary number of controlled vocabularies from Metathesaurus. Experiment shows that our ontology based query expansion scheme achieves 8.2% and 17.7% improvement compared with schemes using pseudo relevance feedback query expansion and using no query expansion respectively. The average improvement is 24.8% in comparison to all other existing strategies. Furthermore, we identify that generalized biomedical concepts are the reason for performance degradation.