Abstract
In this study we analyzed the efficacy of index terms of JSTPlus and JMEDPlus databases. Those databases are produced and provided by Japan Science and Technology Agency (JST). Statistical analysis of user behavior showed that not many users were aware of indexes but got the benefit of indexes and thesaurus. From 52 theme searches, analysis of recall ratio and precision ratio showed that indexes raised retrieval precision. And by using indexes, users could retrieve the articles those were not able to be retrieved only from bibliographic data search. Appearance ratio of index terms in titles, abstracts and full texts showed that 40% of index terms and their synonyms didn't appear in full text. It showed that 40% of index terms were indexed by indexer's subject analysis of full text. These analyses meant efficacy of indexing by hands.
